libgo: update to Go1.15.2 release

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/256618

30 files changed, 704 insertions, 104 deletions

diff --git a/libgo/go/cmd/go/internal/test/test.go b/libgo/go/cmd/go/internal/test/test.go
index 873a76a..77bfc11 100644
--- a/libgo/go/cmd/go/internal/test/test.go
+++ b/libgo/go/cmd/go/internal/test/test.go
@@ -1079,9 +1079,13 @@ func (c *runCache) builderRunTest(b *work.Builder, a *work.Action) error {
 	}
 
 	var stdout io.Writer = os.Stdout
+	var err error
 	if testJSON {
 		json := test2json.NewConverter(lockedStdout{}, a.Package.ImportPath, test2json.Timestamp)
-		defer json.Close()
+		defer func() {
+			json.Exited(err)
+			json.Close()
+		}()
 		stdout = json
 	}
 
@@ -1185,7 +1189,7 @@ func (c *runCache) builderRunTest(b *work.Builder, a *work.Action) error {
 	}
 
 	t0 := time.Now()
-	err := cmd.Start()
+	err = cmd.Start()
 
 	// This is a last-ditch deadline to detect and
 	// stop wedged test binaries, to keep the builders
diff --git a/libgo/go/cmd/go/internal/test/testflag.go b/libgo/go/cmd/go/internal/test/testflag.go
index 1ff34f7..4f0a892 100644
--- a/libgo/go/cmd/go/internal/test/testflag.go
+++ b/libgo/go/cmd/go/internal/test/testflag.go
@@ -214,9 +214,13 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 
 	explicitArgs := make([]string, 0, len(args))
 	inPkgList := false
+	afterFlagWithoutValue := false
 	for len(args) > 0 {
 		f, remainingArgs, err := cmdflag.ParseOne(&CmdTest.Flag, args)
 
+		wasAfterFlagWithoutValue := afterFlagWithoutValue
+		afterFlagWithoutValue = false // provisionally
+
 		if errors.Is(err, flag.ErrHelp) {
 			exitWithUsage()
 		}
@@ -233,10 +237,24 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 		if nf := (cmdflag.NonFlagError{}); errors.As(err, &nf) {
 			if !inPkgList && packageNames != nil {
 				// We already saw the package list previously, and this argument is not
-				// a flag, so it — and everything after it — must be a literal argument
-				// to the test binary.
-				explicitArgs = append(explicitArgs, args...)
-				break
+				// a flag, so it — and everything after it — must be either a value for
+				// a preceding flag or a literal argument to the test binary.
+				if wasAfterFlagWithoutValue {
+					// This argument could syntactically be a flag value, so
+					// optimistically assume that it is and keep looking for go command
+					// flags after it.
+					//
+					// (If we're wrong, we'll at least be consistent with historical
+					// behavior; see https://golang.org/issue/40763.)
+					explicitArgs = append(explicitArgs, nf.RawArg)
+					args = remainingArgs
+					continue
+				} else {
+					// This argument syntactically cannot be a flag value, so it must be a
+					// positional argument, and so must everything after it.
+					explicitArgs = append(explicitArgs, args...)
+					break
+				}
 			}
 
 			inPkgList = true
@@ -272,6 +290,9 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 
 			explicitArgs = append(explicitArgs, nd.RawArg)
 			args = remainingArgs
+			if !nd.HasValue {
+				afterFlagWithoutValue = true
+			}
 			continue
 		}
 
diff --git a/libgo/go/cmd/go/testdata/script/test_flags.txt b/libgo/go/cmd/go/testdata/script/test_flags.txt
new file mode 100644
index 0000000..63385e6
--- /dev/null
+++ b/libgo/go/cmd/go/testdata/script/test_flags.txt
@@ -0,0 +1,132 @@
+env GO111MODULE=on
+
+[short] skip
+
+# Arguments after the flag terminator should be ignored.
+# If we pass '-- -test.v', we should not get verbose output
+# *and* output from the test should not be echoed.
+go test ./x -- -test.v
+stdout '\Aok\s+example.com/x\s+[0-9.s]+\n\z'
+! stderr .
+
+# For backward-compatibility with previous releases of the 'go' command,
+# arguments that appear after unrecognized flags should not be treated
+# as packages, even if they are unambiguously not arguments to flags.
+# Even though ./x looks like a package path, the real package should be
+# the implicit '.'.
+! go test --answer=42 ./x
+stderr '^no Go files in .+$'
+! stderr '/x'
+
+# However, *flags* that appear after unrecognized flags should still be
+# interpreted as flags, under the (possibly-erroneous) assumption that
+# unrecognized flags are non-boolean.
+
+go test -v -x ./x -timeout 24h -boolflag=true foo -timeout 25h
+stdout 'args: foo -timeout 25h'
+stdout 'timeout: 24h0m0s$'  # -timeout is unambiguously not a flag, so the real flag wins.
+
+go test -v -x ./x -timeout 24h -boolflag foo -timeout 25h
+stdout 'args: foo -test\.timeout=25h0m0s'  # For legacy reasons, '-timeout ' is erroneously rewritten to -test.timeout; see https://golang.org/issue/40763.
+stdout 'timeout: 24h0m0s$'  # Actual flag wins.
+
+go test -v -x ./x -timeout 24h -stringflag foo -timeout 25h
+stdout 'args: $'
+stdout 'timeout: 25h0m0s$'  # Later flag wins.
+
+# An explicit '-outputdir=' argument should set test.outputdir
+# to the 'go' command's working directory, not zero it out
+# for the test binary.
+go test -x -coverprofile=cover.out '-outputdir=' ./x
+stderr '-test.outputdir=[^ ]'
+exists ./cover.out
+! exists ./x/cover.out
+
+# Test flags from GOFLAGS should be forwarded to the test binary,
+# with the 'test.' prefix in the GOFLAGS entry...
+env GOFLAGS='-test.timeout=24h0m0s -count=1'
+go test -v -x ./x
+stdout 'timeout: 24h0m0s$'
+stderr '-test.count=1'
+
+# ...or without.
+env GOFLAGS='-timeout=24h0m0s -count=1'
+go test -v -x ./x
+stdout 'timeout: 24h0m0s$'
+stderr '-test.count=1'
+
+# Arguments from the command line should override GOFLAGS...
+go test -v -x -timeout=25h0m0s ./x
+stdout 'timeout: 25h0m0s$'
+stderr '-test.count=1'
+
+# ...even if they use a different flag name.
+go test -v -x -test.timeout=26h0m0s ./x
+stdout 'timeout: 26h0m0s$'
+stderr '-test\.timeout=26h0m0s'
+! stderr 'timeout=24h0m0s'
+stderr '-test.count=1'
+
+# Invalid flags should be reported exactly once.
+! go test -covermode=walrus ./x
+stderr -count=1 'invalid value "walrus" for flag -covermode: valid modes are .*$'
+stderr '^usage: go test .*$'
+stderr '^Run ''go help test'' and ''go help testflag'' for details.$'
+
+# Passing -help to the test binary should show flag help.
+go test ./x -args -help
+stdout 'usage_message'
+
+# -covermode, -coverpkg, and -coverprofile should imply -cover
+go test -covermode=set ./x
+stdout '\s+coverage:\s+'
+
+go test -coverpkg=encoding/binary ./x
+stdout '\s+coverage:\s+'
+
+go test -coverprofile=cover.out ./x
+stdout '\s+coverage:\s+'
+exists ./cover.out
+rm ./cover.out
+
+# -*profile and -trace flags should force output to the current working directory
+# or -outputdir, not the directory containing the test.
+
+go test -memprofile=mem.out ./x
+exists ./mem.out
+rm ./mem.out
+
+go test -trace=trace.out ./x
+exists ./trace.out
+rm ./trace.out
+
+# Relative paths with -outputdir should be relative to the go command's working
+# directory, not the directory containing the test.
+mkdir profiles
+go test -memprofile=mem.out -outputdir=./profiles ./x
+exists ./profiles/mem.out
+rm profiles
+
+-- go.mod --
+module example.com
+go 1.14
+-- x/x_test.go --
+package x
+
+import (
+	"flag"
+	"strings"
+	"testing"
+)
+
+var _ = flag.String("usage_message", "", "dummy flag to check usage message")
+var boolflag = flag.Bool("boolflag", false, "ignored boolean flag")
+var stringflag = flag.String("stringflag", "", "ignored string flag")
+
+func TestLogTimeout(t *testing.T) {
+	t.Logf("timeout: %v", flag.Lookup("test.timeout").Value)
+}
+
+func TestLogArgs(t *testing.T) {
+	t.Logf("args: %s", strings.Join(flag.Args(), " "))
+}
diff --git a/libgo/go/cmd/internal/test2json/test2json.go b/libgo/go/cmd/internal/test2json/test2json.go
index f805213..4eb6dd4 100644
--- a/libgo/go/cmd/internal/test2json/test2json.go
+++ b/libgo/go/cmd/internal/test2json/test2json.go
@@ -45,10 +45,10 @@ type textBytes []byte
 
 func (b textBytes) MarshalText() ([]byte, error) { return b, nil }
 
-// A converter holds the state of a test-to-JSON conversion.
+// A Converter holds the state of a test-to-JSON conversion.
 // It implements io.WriteCloser; the caller writes test output in,
 // and the converter writes JSON output to w.
-type converter struct {
+type Converter struct {
 	w        io.Writer  // JSON output stream
 	pkg      string     // package to name in events
 	mode     Mode       // mode bits
@@ -100,9 +100,9 @@ var (
 //
 // The pkg string, if present, specifies the import path to
 // report in the JSON stream.
-func NewConverter(w io.Writer, pkg string, mode Mode) io.WriteCloser {
-	c := new(converter)
-	*c = converter{
+func NewConverter(w io.Writer, pkg string, mode Mode) *Converter {
+	c := new(Converter)
+	*c = Converter{
 		w:     w,
 		pkg:   pkg,
 		mode:  mode,
@@ -122,15 +122,31 @@ func NewConverter(w io.Writer, pkg string, mode Mode) io.WriteCloser {
 }
 
 // Write writes the test input to the converter.
-func (c *converter) Write(b []byte) (int, error) {
+func (c *Converter) Write(b []byte) (int, error) {
 	c.input.write(b)
 	return len(b), nil
 }
 
+// Exited marks the test process as having exited with the given error.
+func (c *Converter) Exited(err error) {
+	if err == nil {
+		c.result = "pass"
+	} else {
+		c.result = "fail"
+	}
+}
+
 var (
+	// printed by test on successful run.
 	bigPass = []byte("PASS\n")
+
+	// printed by test after a normal test failure.
 	bigFail = []byte("FAIL\n")
 
+	// printed by 'go test' along with an error if the test binary terminates
+	// with an error.
+	bigFailErrorPrefix = []byte("FAIL\t")
+
 	updates = [][]byte{
 		[]byte("=== RUN   "),
 		[]byte("=== PAUSE "),
@@ -153,9 +169,9 @@ var (
 // handleInputLine handles a single whole test output line.
 // It must write the line to c.output but may choose to do so
 // before or after emitting other events.
-func (c *converter) handleInputLine(line []byte) {
+func (c *Converter) handleInputLine(line []byte) {
 	// Final PASS or FAIL.
-	if bytes.Equal(line, bigPass) || bytes.Equal(line, bigFail) {
+	if bytes.Equal(line, bigPass) || bytes.Equal(line, bigFail) || bytes.HasPrefix(line, bigFailErrorPrefix) {
 		c.flushReport(0)
 		c.output.write(line)
 		if bytes.Equal(line, bigPass) {
@@ -204,8 +220,18 @@ func (c *converter) handleInputLine(line []byte) {
 		}
 	}
 
+	// Not a special test output line.
 	if !ok {
-		// Not a special test output line.
+		// Lookup the name of the test which produced the output using the
+		// indentation of the output as an index into the stack of the current
+		// subtests.
+		// If the indentation is greater than the number of current subtests
+		// then the output must have included extra indentation. We can't
+		// determine which subtest produced this output, so we default to the
+		// old behaviour of assuming the most recently run subtest produced it.
+		if indent > 0 && indent <= len(c.report) {
+			c.testName = c.report[indent-1].Test
+		}
 		c.output.write(origLine)
 		return
 	}
@@ -269,7 +295,7 @@ func (c *converter) handleInputLine(line []byte) {
 }
 
 // flushReport flushes all pending PASS/FAIL reports at levels >= depth.
-func (c *converter) flushReport(depth int) {
+func (c *Converter) flushReport(depth int) {
 	c.testName = ""
 	for len(c.report) > depth {
 		e := c.report[len(c.report)-1]
@@ -281,23 +307,22 @@ func (c *converter) flushReport(depth int) {
 // Close marks the end of the go test output.
 // It flushes any pending input and then output (only partial lines at this point)
 // and then emits the final overall package-level pass/fail event.
-func (c *converter) Close() error {
+func (c *Converter) Close() error {
 	c.input.flush()
 	c.output.flush()
-	e := &event{Action: "fail"}
 	if c.result != "" {
-		e.Action = c.result
-	}
-	if c.mode&Timestamp != 0 {
-		dt := time.Since(c.start).Round(1 * time.Millisecond).Seconds()
-		e.Elapsed = &dt
+		e := &event{Action: c.result}
+		if c.mode&Timestamp != 0 {
+			dt := time.Since(c.start).Round(1 * time.Millisecond).Seconds()
+			e.Elapsed = &dt
+		}
+		c.writeEvent(e)
 	}
-	c.writeEvent(e)
 	return nil
 }
 
 // writeOutputEvent writes a single output event with the given bytes.
-func (c *converter) writeOutputEvent(out []byte) {
+func (c *Converter) writeOutputEvent(out []byte) {
 	c.writeEvent(&event{
 		Action: "output",
 		Output: (*textBytes)(&out),
@@ -306,7 +331,7 @@ func (c *converter) writeOutputEvent(out []byte) {
 
 // writeEvent writes a single event.
 // It adds the package, time (if requested), and test name (if needed).
-func (c *converter) writeEvent(e *event) {
+func (c *Converter) writeEvent(e *event) {
 	e.Package = c.pkg
 	if c.mode&Timestamp != 0 {
 		t := time.Now()
diff --git a/libgo/go/cmd/internal/test2json/testdata/benchshort.json b/libgo/go/cmd/internal/test2json/testdata/benchshort.json
index 8c61d95..34b03b9 100644
--- a/libgo/go/cmd/internal/test2json/testdata/benchshort.json
+++ b/libgo/go/cmd/internal/test2json/testdata/benchshort.json
@@ -4,4 +4,3 @@
 {"Action":"output","Output":"# but to avoid questions of timing, we just use a file with no \\n at all.\n"}
 {"Action":"output","Output":"BenchmarkFoo   \t"}
 {"Action":"output","Output":"10000 early EOF"}
-{"Action":"fail"}
diff --git a/libgo/go/cmd/internal/test2json/testdata/empty.json b/libgo/go/cmd/internal/test2json/testdata/empty.json
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/libgo/go/cmd/internal/test2json/testdata/empty.json
diff --git a/libgo/go/cmd/internal/test2json/testdata/empty.test b/libgo/go/cmd/internal/test2json/testdata/empty.test
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/libgo/go/cmd/internal/test2json/testdata/empty.test
diff --git a/libgo/go/cmd/internal/test2json/testdata/issue29755.json b/libgo/go/cmd/internal/test2json/testdata/issue29755.json
new file mode 100644
index 0000000..2e8ba48
--- /dev/null
+++ b/libgo/go/cmd/internal/test2json/testdata/issue29755.json
@@ -0,0 +1,38 @@
+{"Action":"run","Test":"TestOutputWithSubtest"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"=== RUN   TestOutputWithSubtest\n"}
+{"Action":"run","Test":"TestOutputWithSubtest/sub_test"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test","Output":"=== RUN   TestOutputWithSubtest/sub_test\n"}
+{"Action":"run","Test":"TestOutputWithSubtest/sub_test/sub2"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test/sub2","Output":"=== RUN   TestOutputWithSubtest/sub_test/sub2\n"}
+{"Action":"run","Test":"TestOutputWithSubtest/sub_test2"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2","Output":"=== RUN   TestOutputWithSubtest/sub_test2\n"}
+{"Action":"run","Test":"TestOutputWithSubtest/sub_test2/sub2"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2/sub2","Output":"=== RUN   TestOutputWithSubtest/sub_test2/sub2\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"--- FAIL: TestOutputWithSubtest (0.00s)\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"    foo_test.go:6: output before sub tests\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"    foo_test.go:10: output from root test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"    foo_test.go:15: output from root test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test","Output":"    --- PASS: TestOutputWithSubtest/sub_test (0.00s)\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test","Output":"        foo_test.go:9: output from sub test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test","Output":"        foo_test.go:11: more output from sub test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test","Output":"        foo_test.go:16: more output from sub test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test/sub2","Output":"        --- PASS: TestOutputWithSubtest/sub_test/sub2 (0.00s)\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test/sub2","Output":"            foo_test.go:14: output from sub2 test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"    foo_test.go:22: output from root test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"    foo_test.go:27: output from root test\n"}
+{"Action":"pass","Test":"TestOutputWithSubtest/sub_test/sub2"}
+{"Action":"pass","Test":"TestOutputWithSubtest/sub_test"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2","Output":"    --- PASS: TestOutputWithSubtest/sub_test2 (0.00s)\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2","Output":"        foo_test.go:21: output from sub test2\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2","Output":"        foo_test.go:23: more output from sub test2\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2","Output":"        foo_test.go:28: more output from sub test2\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2/sub2","Output":"        --- PASS: TestOutputWithSubtest/sub_test2/sub2 (0.00s)\n"}
+{"Action":"output","Test":"TestOutputWithSubtest/sub_test2/sub2","Output":"            foo_test.go:26: output from sub2 test\n"}
+{"Action":"output","Test":"TestOutputWithSubtest","Output":"    foo_test.go:32: output after sub test\n"}
+{"Action":"pass","Test":"TestOutputWithSubtest/sub_test2/sub2"}
+{"Action":"pass","Test":"TestOutputWithSubtest/sub_test2"}
+{"Action":"fail","Test":"TestOutputWithSubtest"}
+{"Action":"output","Output":"FAIL\n"}
+{"Action":"output","Output":"FAIL\tgotest.tools/gotestsum/foo\t0.001s\n"}
+{"Action":"output","Output":"FAIL\n"}
+{"Action":"fail"}
diff --git a/libgo/go/cmd/internal/test2json/testdata/issue29755.test b/libgo/go/cmd/internal/test2json/testdata/issue29755.test
new file mode 100644
index 0000000..b0c596c
--- /dev/null
+++ b/libgo/go/cmd/internal/test2json/testdata/issue29755.test
@@ -0,0 +1,27 @@
+=== RUN   TestOutputWithSubtest
+=== RUN   TestOutputWithSubtest/sub_test
+=== RUN   TestOutputWithSubtest/sub_test/sub2
+=== RUN   TestOutputWithSubtest/sub_test2
+=== RUN   TestOutputWithSubtest/sub_test2/sub2
+--- FAIL: TestOutputWithSubtest (0.00s)
+    foo_test.go:6: output before sub tests
+    foo_test.go:10: output from root test
+    foo_test.go:15: output from root test
+    --- PASS: TestOutputWithSubtest/sub_test (0.00s)
+        foo_test.go:9: output from sub test
+        foo_test.go:11: more output from sub test
+        foo_test.go:16: more output from sub test
+        --- PASS: TestOutputWithSubtest/sub_test/sub2 (0.00s)
+            foo_test.go:14: output from sub2 test
+    foo_test.go:22: output from root test
+    foo_test.go:27: output from root test
+    --- PASS: TestOutputWithSubtest/sub_test2 (0.00s)
+        foo_test.go:21: output from sub test2
+        foo_test.go:23: more output from sub test2
+        foo_test.go:28: more output from sub test2
+        --- PASS: TestOutputWithSubtest/sub_test2/sub2 (0.00s)
+            foo_test.go:26: output from sub2 test
+    foo_test.go:32: output after sub test
+FAIL
+FAIL	gotest.tools/gotestsum/foo	0.001s
+FAIL
diff --git a/libgo/go/cmd/internal/test2json/testdata/panic.json b/libgo/go/cmd/internal/test2json/testdata/panic.json
new file mode 100644
index 0000000..f773814
--- /dev/null
+++ b/libgo/go/cmd/internal/test2json/testdata/panic.json
@@ -0,0 +1,19 @@
+{"Action":"output","Test":"TestPanic","Output":"--- FAIL: TestPanic (0.00s)\n"}
+{"Action":"output","Test":"TestPanic","Output":"panic: oops [recovered]\n"}
+{"Action":"output","Test":"TestPanic","Output":"\tpanic: oops\n"}
+{"Action":"output","Test":"TestPanic","Output":"\n"}
+{"Action":"output","Test":"TestPanic","Output":"goroutine 7 [running]:\n"}
+{"Action":"output","Test":"TestPanic","Output":"testing.tRunner.func1(0xc000092100)\n"}
+{"Action":"output","Test":"TestPanic","Output":"\t/go/src/testing/testing.go:874 +0x3a3\n"}
+{"Action":"output","Test":"TestPanic","Output":"panic(0x1110ea0, 0x116aea0)\n"}
+{"Action":"output","Test":"TestPanic","Output":"\t/go/src/runtime/panic.go:679 +0x1b2\n"}
+{"Action":"output","Test":"TestPanic","Output":"command-line-arguments.TestPanic(0xc000092100)\n"}
+{"Action":"output","Test":"TestPanic","Output":"\ta_test.go:6 +0x39\n"}
+{"Action":"output","Test":"TestPanic","Output":"testing.tRunner(0xc000092100, 0x114f500)\n"}
+{"Action":"output","Test":"TestPanic","Output":"\tgo/src/testing/testing.go:909 +0xc9\n"}
+{"Action":"output","Test":"TestPanic","Output":"created by testing.(*T).Run\n"}
+{"Action":"output","Test":"TestPanic","Output":"\tgo/src/testing/testing.go:960 +0x350\n"}
+{"Action":"fail","Test":"TestPanic"}
+{"Action":"output","Output":"FAIL\tcommand-line-arguments\t0.042s\n"}
+{"Action":"output","Output":"FAIL\n"}
+{"Action":"fail"}
diff --git a/libgo/go/cmd/internal/test2json/testdata/panic.test b/libgo/go/cmd/internal/test2json/testdata/panic.test
new file mode 100644
index 0000000..517ebaf
--- /dev/null
+++ b/libgo/go/cmd/internal/test2json/testdata/panic.test
@@ -0,0 +1,17 @@
+--- FAIL: TestPanic (0.00s)
+panic: oops [recovered]
+	panic: oops
+
+goroutine 7 [running]:
+testing.tRunner.func1(0xc000092100)
+	/go/src/testing/testing.go:874 +0x3a3
+panic(0x1110ea0, 0x116aea0)
+	/go/src/runtime/panic.go:679 +0x1b2
+command-line-arguments.TestPanic(0xc000092100)
+	a_test.go:6 +0x39
+testing.tRunner(0xc000092100, 0x114f500)
+	go/src/testing/testing.go:909 +0xc9
+created by testing.(*T).Run
+	go/src/testing/testing.go:960 +0x350
+FAIL	command-line-arguments	0.042s
+FAIL
diff --git a/libgo/go/cmd/internal/test2json/testdata/smiley.json b/libgo/go/cmd/internal/test2json/testdata/smiley.json
index afa990d..f49180d 100644
--- a/libgo/go/cmd/internal/test2json/testdata/smiley.json
+++ b/libgo/go/cmd/internal/test2json/testdata/smiley.json
@@ -116,13 +116,13 @@
 {"Action":"output","Test":"Test☺☹/2","Output":"=== CONT  Test☺☹/2\n"}
 {"Action":"output","Test":"TestTags","Output":"--- PASS: TestTags (0.00s)\n"}
 {"Action":"output","Test":"TestTags/x_testtag_y","Output":"    --- PASS: TestTags/x_testtag_y (0.04s)\n"}
-{"Action":"output","Test":"TestTags/x_testtag_y","Output":"    \tvet_test.go:187: -tags=x testtag y\n"}
+{"Action":"output","Test":"TestTags/x_testtag_y","Output":"        vet_test.go:187: -tags=x testtag y\n"}
 {"Action":"pass","Test":"TestTags/x_testtag_y"}
 {"Action":"output","Test":"TestTags/x,testtag,y","Output":"    --- PASS: TestTags/x,testtag,y (0.04s)\n"}
-{"Action":"output","Test":"TestTags/x,testtag,y","Output":"    \tvet_test.go:187: -tags=x,testtag,y\n"}
+{"Action":"output","Test":"TestTags/x,testtag,y","Output":"        vet_test.go:187: -tags=x,testtag,y\n"}
 {"Action":"pass","Test":"TestTags/x,testtag,y"}
 {"Action":"output","Test":"TestTags/testtag","Output":"    --- PASS: TestTags/testtag (0.04s)\n"}
-{"Action":"output","Test":"TestTags/testtag","Output":"    \tvet_test.go:187: -tags=testtag\n"}
+{"Action":"output","Test":"TestTags/testtag","Output":"        vet_test.go:187: -tags=testtag\n"}
 {"Action":"pass","Test":"TestTags/testtag"}
 {"Action":"pass","Test":"TestTags"}
 {"Action":"cont","Test":"Test☺☹/1"}
@@ -139,28 +139,28 @@
 {"Action":"output","Test":"Test☺☹Dirs/cgo","Output":"=== CONT  Test☺☹Dirs/cgo\n"}
 {"Action":"output","Test":"Test☺☹","Output":"--- PASS: Test☺☹ (0.39s)\n"}
 {"Action":"output","Test":"Test☺☹/5","Output":"    --- PASS: Test☺☹/5 (0.07s)\n"}
-{"Action":"output","Test":"Test☺☹/5","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/copylock_func.go\" \"testdata/rangeloop.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/5","Output":"        vet_test.go:114: φιλεσ: [\"testdata/copylock_func.go\" \"testdata/rangeloop.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/5"}
 {"Action":"output","Test":"Test☺☹/3","Output":"    --- PASS: Test☺☹/3 (0.07s)\n"}
-{"Action":"output","Test":"Test☺☹/3","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/composite.go\" \"testdata/nilfunc.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/3","Output":"        vet_test.go:114: φιλεσ: [\"testdata/composite.go\" \"testdata/nilfunc.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/3"}
 {"Action":"output","Test":"Test☺☹/6","Output":"    --- PASS: Test☺☹/6 (0.07s)\n"}
-{"Action":"output","Test":"Test☺☹/6","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/copylock_range.go\" \"testdata/shadow.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/6","Output":"        vet_test.go:114: φιλεσ: [\"testdata/copylock_range.go\" \"testdata/shadow.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/6"}
 {"Action":"output","Test":"Test☺☹/2","Output":"    --- PASS: Test☺☹/2 (0.07s)\n"}
-{"Action":"output","Test":"Test☺☹/2","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/bool.go\" \"testdata/method.go\" \"testdata/unused.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/2","Output":"        vet_test.go:114: φιλεσ: [\"testdata/bool.go\" \"testdata/method.go\" \"testdata/unused.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/2"}
 {"Action":"output","Test":"Test☺☹/0","Output":"    --- PASS: Test☺☹/0 (0.13s)\n"}
-{"Action":"output","Test":"Test☺☹/0","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/assign.go\" \"testdata/httpresponse.go\" \"testdata/structtag.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/0","Output":"        vet_test.go:114: φιλεσ: [\"testdata/assign.go\" \"testdata/httpresponse.go\" \"testdata/structtag.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/0"}
 {"Action":"output","Test":"Test☺☹/4","Output":"    --- PASS: Test☺☹/4 (0.16s)\n"}
-{"Action":"output","Test":"Test☺☹/4","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/copylock.go\" \"testdata/print.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/4","Output":"        vet_test.go:114: φιλεσ: [\"testdata/copylock.go\" \"testdata/print.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/4"}
 {"Action":"output","Test":"Test☺☹/1","Output":"    --- PASS: Test☺☹/1 (0.07s)\n"}
-{"Action":"output","Test":"Test☺☹/1","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/atomic.go\" \"testdata/lostcancel.go\" \"testdata/unsafeptr.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/1","Output":"        vet_test.go:114: φιλεσ: [\"testdata/atomic.go\" \"testdata/lostcancel.go\" \"testdata/unsafeptr.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/1"}
 {"Action":"output","Test":"Test☺☹/7","Output":"    --- PASS: Test☺☹/7 (0.19s)\n"}
-{"Action":"output","Test":"Test☺☹/7","Output":"    \tvet_test.go:114: φιλεσ: [\"testdata/deadcode.go\" \"testdata/shift.go\"]\n"}
+{"Action":"output","Test":"Test☺☹/7","Output":"        vet_test.go:114: φιλεσ: [\"testdata/deadcode.go\" \"testdata/shift.go\"]\n"}
 {"Action":"pass","Test":"Test☺☹/7"}
 {"Action":"pass","Test":"Test☺☹"}
 {"Action":"output","Test":"Test☺☹Dirs","Output":"--- PASS: Test☺☹Dirs (0.01s)\n"}
diff --git a/libgo/go/cmd/internal/test2json/testdata/smiley.test b/libgo/go/cmd/internal/test2json/testdata/smiley.test
index 05edf5a..bd1ed2d 100644
--- a/libgo/go/cmd/internal/test2json/testdata/smiley.test
+++ b/libgo/go/cmd/internal/test2json/testdata/smiley.test
@@ -58,11 +58,11 @@
 === CONT  Test☺☹/2
 --- PASS: TestTags (0.00s)
     --- PASS: TestTags/x_testtag_y (0.04s)
-    	vet_test.go:187: -tags=x testtag y
+        vet_test.go:187: -tags=x testtag y
     --- PASS: TestTags/x,testtag,y (0.04s)
-    	vet_test.go:187: -tags=x,testtag,y
+        vet_test.go:187: -tags=x,testtag,y
     --- PASS: TestTags/testtag (0.04s)
-    	vet_test.go:187: -tags=testtag
+        vet_test.go:187: -tags=testtag
 === CONT  Test☺☹/1
 === CONT  Test☺☹Dirs/testingpkg
 === CONT  Test☺☹Dirs/buildtag
@@ -71,21 +71,21 @@
 === CONT  Test☺☹Dirs/cgo
 --- PASS: Test☺☹ (0.39s)
     --- PASS: Test☺☹/5 (0.07s)
-    	vet_test.go:114: φιλεσ: ["testdata/copylock_func.go" "testdata/rangeloop.go"]
+        vet_test.go:114: φιλεσ: ["testdata/copylock_func.go" "testdata/rangeloop.go"]
     --- PASS: Test☺☹/3 (0.07s)
-    	vet_test.go:114: φιλεσ: ["testdata/composite.go" "testdata/nilfunc.go"]
+        vet_test.go:114: φιλεσ: ["testdata/composite.go" "testdata/nilfunc.go"]
     --- PASS: Test☺☹/6 (0.07s)
-    	vet_test.go:114: φιλεσ: ["testdata/copylock_range.go" "testdata/shadow.go"]
+        vet_test.go:114: φιλεσ: ["testdata/copylock_range.go" "testdata/shadow.go"]
     --- PASS: Test☺☹/2 (0.07s)
-    	vet_test.go:114: φιλεσ: ["testdata/bool.go" "testdata/method.go" "testdata/unused.go"]
+        vet_test.go:114: φιλεσ: ["testdata/bool.go" "testdata/method.go" "testdata/unused.go"]
     --- PASS: Test☺☹/0 (0.13s)
-    	vet_test.go:114: φιλεσ: ["testdata/assign.go" "testdata/httpresponse.go" "testdata/structtag.go"]
+        vet_test.go:114: φιλεσ: ["testdata/assign.go" "testdata/httpresponse.go" "testdata/structtag.go"]
     --- PASS: Test☺☹/4 (0.16s)
-    	vet_test.go:114: φιλεσ: ["testdata/copylock.go" "testdata/print.go"]
+        vet_test.go:114: φιλεσ: ["testdata/copylock.go" "testdata/print.go"]
     --- PASS: Test☺☹/1 (0.07s)
-    	vet_test.go:114: φιλεσ: ["testdata/atomic.go" "testdata/lostcancel.go" "testdata/unsafeptr.go"]
+        vet_test.go:114: φιλεσ: ["testdata/atomic.go" "testdata/lostcancel.go" "testdata/unsafeptr.go"]
     --- PASS: Test☺☹/7 (0.19s)
-    	vet_test.go:114: φιλεσ: ["testdata/deadcode.go" "testdata/shift.go"]
+        vet_test.go:114: φιλεσ: ["testdata/deadcode.go" "testdata/shift.go"]
 --- PASS: Test☺☹Dirs (0.01s)
     --- PASS: Test☺☹Dirs/testingpkg (0.06s)
     --- PASS: Test☺☹Dirs/divergent (0.05s)
diff --git a/libgo/go/cmd/internal/test2json/testdata/vet.json b/libgo/go/cmd/internal/test2json/testdata/vet.json
index 8c5921d..2558d61 100644
--- a/libgo/go/cmd/internal/test2json/testdata/vet.json
+++ b/libgo/go/cmd/internal/test2json/testdata/vet.json
@@ -116,13 +116,13 @@
 {"Action":"output","Test":"TestVet/2","Output":"=== CONT  TestVet/2\n"}
 {"Action":"output","Test":"TestTags","Output":"--- PASS: TestTags (0.00s)\n"}
 {"Action":"output","Test":"TestTags/x_testtag_y","Output":"    --- PASS: TestTags/x_testtag_y (0.04s)\n"}
-{"Action":"output","Test":"TestTags/x_testtag_y","Output":"    \tvet_test.go:187: -tags=x testtag y\n"}
+{"Action":"output","Test":"TestTags/x_testtag_y","Output":"        vet_test.go:187: -tags=x testtag y\n"}
 {"Action":"pass","Test":"TestTags/x_testtag_y"}
 {"Action":"output","Test":"TestTags/x,testtag,y","Output":"    --- PASS: TestTags/x,testtag,y (0.04s)\n"}
-{"Action":"output","Test":"TestTags/x,testtag,y","Output":"    \tvet_test.go:187: -tags=x,testtag,y\n"}
+{"Action":"output","Test":"TestTags/x,testtag,y","Output":"        vet_test.go:187: -tags=x,testtag,y\n"}
 {"Action":"pass","Test":"TestTags/x,testtag,y"}
 {"Action":"output","Test":"TestTags/testtag","Output":"    --- PASS: TestTags/testtag (0.04s)\n"}
-{"Action":"output","Test":"TestTags/testtag","Output":"    \tvet_test.go:187: -tags=testtag\n"}
+{"Action":"output","Test":"TestTags/testtag","Output":"        vet_test.go:187: -tags=testtag\n"}
 {"Action":"pass","Test":"TestTags/testtag"}
 {"Action":"pass","Test":"TestTags"}
 {"Action":"cont","Test":"TestVet/1"}
@@ -139,28 +139,28 @@
 {"Action":"output","Test":"TestVetDirs/cgo","Output":"=== CONT  TestVetDirs/cgo\n"}
 {"Action":"output","Test":"TestVet","Output":"--- PASS: TestVet (0.39s)\n"}
 {"Action":"output","Test":"TestVet/5","Output":"    --- PASS: TestVet/5 (0.07s)\n"}
-{"Action":"output","Test":"TestVet/5","Output":"    \tvet_test.go:114: files: [\"testdata/copylock_func.go\" \"testdata/rangeloop.go\"]\n"}
+{"Action":"output","Test":"TestVet/5","Output":"        vet_test.go:114: files: [\"testdata/copylock_func.go\" \"testdata/rangeloop.go\"]\n"}
 {"Action":"pass","Test":"TestVet/5"}
 {"Action":"output","Test":"TestVet/3","Output":"    --- PASS: TestVet/3 (0.07s)\n"}
-{"Action":"output","Test":"TestVet/3","Output":"    \tvet_test.go:114: files: [\"testdata/composite.go\" \"testdata/nilfunc.go\"]\n"}
+{"Action":"output","Test":"TestVet/3","Output":"        vet_test.go:114: files: [\"testdata/composite.go\" \"testdata/nilfunc.go\"]\n"}
 {"Action":"pass","Test":"TestVet/3"}
 {"Action":"output","Test":"TestVet/6","Output":"    --- PASS: TestVet/6 (0.07s)\n"}
-{"Action":"output","Test":"TestVet/6","Output":"    \tvet_test.go:114: files: [\"testdata/copylock_range.go\" \"testdata/shadow.go\"]\n"}
+{"Action":"output","Test":"TestVet/6","Output":"        vet_test.go:114: files: [\"testdata/copylock_range.go\" \"testdata/shadow.go\"]\n"}
 {"Action":"pass","Test":"TestVet/6"}
 {"Action":"output","Test":"TestVet/2","Output":"    --- PASS: TestVet/2 (0.07s)\n"}
-{"Action":"output","Test":"TestVet/2","Output":"    \tvet_test.go:114: files: [\"testdata/bool.go\" \"testdata/method.go\" \"testdata/unused.go\"]\n"}
+{"Action":"output","Test":"TestVet/2","Output":"        vet_test.go:114: files: [\"testdata/bool.go\" \"testdata/method.go\" \"testdata/unused.go\"]\n"}
 {"Action":"pass","Test":"TestVet/2"}
 {"Action":"output","Test":"TestVet/0","Output":"    --- PASS: TestVet/0 (0.13s)\n"}
-{"Action":"output","Test":"TestVet/0","Output":"    \tvet_test.go:114: files: [\"testdata/assign.go\" \"testdata/httpresponse.go\" \"testdata/structtag.go\"]\n"}
+{"Action":"output","Test":"TestVet/0","Output":"        vet_test.go:114: files: [\"testdata/assign.go\" \"testdata/httpresponse.go\" \"testdata/structtag.go\"]\n"}
 {"Action":"pass","Test":"TestVet/0"}
 {"Action":"output","Test":"TestVet/4","Output":"    --- PASS: TestVet/4 (0.16s)\n"}
-{"Action":"output","Test":"TestVet/4","Output":"    \tvet_test.go:114: files: [\"testdata/copylock.go\" \"testdata/print.go\"]\n"}
+{"Action":"output","Test":"TestVet/4","Output":"        vet_test.go:114: files: [\"testdata/copylock.go\" \"testdata/print.go\"]\n"}
 {"Action":"pass","Test":"TestVet/4"}
 {"Action":"output","Test":"TestVet/1","Output":"    --- PASS: TestVet/1 (0.07s)\n"}
-{"Action":"output","Test":"TestVet/1","Output":"    \tvet_test.go:114: files: [\"testdata/atomic.go\" \"testdata/lostcancel.go\" \"testdata/unsafeptr.go\"]\n"}
+{"Action":"output","Test":"TestVet/1","Output":"        vet_test.go:114: files: [\"testdata/atomic.go\" \"testdata/lostcancel.go\" \"testdata/unsafeptr.go\"]\n"}
 {"Action":"pass","Test":"TestVet/1"}
 {"Action":"output","Test":"TestVet/7","Output":"    --- PASS: TestVet/7 (0.19s)\n"}
-{"Action":"output","Test":"TestVet/7","Output":"    \tvet_test.go:114: files: [\"testdata/deadcode.go\" \"testdata/shift.go\"]\n"}
+{"Action":"output","Test":"TestVet/7","Output":"        vet_test.go:114: files: [\"testdata/deadcode.go\" \"testdata/shift.go\"]\n"}
 {"Action":"pass","Test":"TestVet/7"}
 {"Action":"pass","Test":"TestVet"}
 {"Action":"output","Test":"TestVetDirs","Output":"--- PASS: TestVetDirs (0.01s)\n"}
diff --git a/libgo/go/cmd/internal/test2json/testdata/vet.test b/libgo/go/cmd/internal/test2json/testdata/vet.test
index 3389559..59d187e 100644
--- a/libgo/go/cmd/internal/test2json/testdata/vet.test
+++ b/libgo/go/cmd/internal/test2json/testdata/vet.test
@@ -58,11 +58,11 @@
 === CONT  TestVet/2
 --- PASS: TestTags (0.00s)
     --- PASS: TestTags/x_testtag_y (0.04s)
-    	vet_test.go:187: -tags=x testtag y
+        vet_test.go:187: -tags=x testtag y
     --- PASS: TestTags/x,testtag,y (0.04s)
-    	vet_test.go:187: -tags=x,testtag,y
+        vet_test.go:187: -tags=x,testtag,y
     --- PASS: TestTags/testtag (0.04s)
-    	vet_test.go:187: -tags=testtag
+        vet_test.go:187: -tags=testtag
 === CONT  TestVet/1
 === CONT  TestVetDirs/testingpkg
 === CONT  TestVetDirs/buildtag
@@ -71,21 +71,21 @@
 === CONT  TestVetDirs/cgo
 --- PASS: TestVet (0.39s)
     --- PASS: TestVet/5 (0.07s)
-    	vet_test.go:114: files: ["testdata/copylock_func.go" "testdata/rangeloop.go"]
+        vet_test.go:114: files: ["testdata/copylock_func.go" "testdata/rangeloop.go"]
     --- PASS: TestVet/3 (0.07s)
-    	vet_test.go:114: files: ["testdata/composite.go" "testdata/nilfunc.go"]
+        vet_test.go:114: files: ["testdata/composite.go" "testdata/nilfunc.go"]
     --- PASS: TestVet/6 (0.07s)
-    	vet_test.go:114: files: ["testdata/copylock_range.go" "testdata/shadow.go"]
+        vet_test.go:114: files: ["testdata/copylock_range.go" "testdata/shadow.go"]
     --- PASS: TestVet/2 (0.07s)
-    	vet_test.go:114: files: ["testdata/bool.go" "testdata/method.go" "testdata/unused.go"]
+        vet_test.go:114: files: ["testdata/bool.go" "testdata/method.go" "testdata/unused.go"]
     --- PASS: TestVet/0 (0.13s)
-    	vet_test.go:114: files: ["testdata/assign.go" "testdata/httpresponse.go" "testdata/structtag.go"]
+        vet_test.go:114: files: ["testdata/assign.go" "testdata/httpresponse.go" "testdata/structtag.go"]
     --- PASS: TestVet/4 (0.16s)
-    	vet_test.go:114: files: ["testdata/copylock.go" "testdata/print.go"]
+        vet_test.go:114: files: ["testdata/copylock.go" "testdata/print.go"]
     --- PASS: TestVet/1 (0.07s)
-    	vet_test.go:114: files: ["testdata/atomic.go" "testdata/lostcancel.go" "testdata/unsafeptr.go"]
+        vet_test.go:114: files: ["testdata/atomic.go" "testdata/lostcancel.go" "testdata/unsafeptr.go"]
     --- PASS: TestVet/7 (0.19s)
-    	vet_test.go:114: files: ["testdata/deadcode.go" "testdata/shift.go"]
+        vet_test.go:114: files: ["testdata/deadcode.go" "testdata/shift.go"]
 --- PASS: TestVetDirs (0.01s)
     --- PASS: TestVetDirs/testingpkg (0.06s)
     --- PASS: TestVetDirs/divergent (0.05s)
diff --git a/libgo/go/cmd/test2json/main.go b/libgo/go/cmd/test2json/main.go
index 0385d8f2..57a8741 100644
--- a/libgo/go/cmd/test2json/main.go
+++ b/libgo/go/cmd/test2json/main.go
@@ -118,12 +118,16 @@ func main() {
 		w := &countWriter{0, c}
 		cmd.Stdout = w
 		cmd.Stderr = w
-		if err := cmd.Run(); err != nil {
+		err := cmd.Run()
+		if err != nil {
 			if w.n > 0 {
 				// Assume command printed why it failed.
 			} else {
 				fmt.Fprintf(c, "test2json: %v\n", err)
 			}
+		}
+		c.Exited(err)
+		if err != nil {
 			c.Close()
 			os.Exit(1)
 		}
diff --git a/libgo/go/internal/poll/copy_file_range_linux.go b/libgo/go/internal/poll/copy_file_range_linux.go
index 604607f..09de299 100644
--- a/libgo/go/internal/poll/copy_file_range_linux.go
+++ b/libgo/go/internal/poll/copy_file_range_linux.go
@@ -41,7 +41,7 @@ func CopyFileRange(dst, src *FD, remain int64) (written int64, handled bool, err
 			// use copy_file_range(2) again.
 			atomic.StoreInt32(&copyFileRangeSupported, 0)
 			return 0, false, nil
-		case syscall.EXDEV, syscall.EINVAL:
+		case syscall.EXDEV, syscall.EINVAL, syscall.EOPNOTSUPP, syscall.EPERM:
 			// Prior to Linux 5.3, it was not possible to
 			// copy_file_range across file systems. Similarly to
 			// the ENOSYS case above, if we see EXDEV, we have
@@ -52,6 +52,14 @@ func CopyFileRange(dst, src *FD, remain int64) (written int64, handled bool, err
 			// dst or src refer to a pipe rather than a regular
 			// file. This is another case where no data has been
 			// transfered, so we consider it unhandled.
+			//
+			// If the file is on NFS, we can see EOPNOTSUPP.
+			// See issue #40731.
+			//
+			// If the process is running inside a Docker container,
+			// we might see EPERM instead of ENOSYS. See issue
+			// #40893. Since EPERM might also be a legitimate error,
+			// don't mark copy_file_range(2) as unsupported.
 			return 0, false, nil
 		case nil:
 			if n == 0 {
diff --git a/libgo/go/net/http/cgi/child.go b/libgo/go/net/http/cgi/child.go
index 9474175..61de616 100644
--- a/libgo/go/net/http/cgi/child.go
+++ b/libgo/go/net/http/cgi/child.go
@@ -163,10 +163,12 @@ func Serve(handler http.Handler) error {
 }
 
 type response struct {
-	req        *http.Request
-	header     http.Header
-	bufw       *bufio.Writer
-	headerSent bool
+	req            *http.Request
+	header         http.Header
+	code           int
+	wroteHeader    bool
+	wroteCGIHeader bool
+	bufw           *bufio.Writer
 }
 
 func (r *response) Flush() {
@@ -178,26 +180,38 @@ func (r *response) Header() http.Header {
 }
 
 func (r *response) Write(p []byte) (n int, err error) {
-	if !r.headerSent {
+	if !r.wroteHeader {
 		r.WriteHeader(http.StatusOK)
 	}
+	if !r.wroteCGIHeader {
+		r.writeCGIHeader(p)
+	}
 	return r.bufw.Write(p)
 }
 
 func (r *response) WriteHeader(code int) {
-	if r.headerSent {
+	if r.wroteHeader {
 		// Note: explicitly using Stderr, as Stdout is our HTTP output.
 		fmt.Fprintf(os.Stderr, "CGI attempted to write header twice on request for %s", r.req.URL)
 		return
 	}
-	r.headerSent = true
-	fmt.Fprintf(r.bufw, "Status: %d %s\r\n", code, http.StatusText(code))
+	r.wroteHeader = true
+	r.code = code
+}
 
-	// Set a default Content-Type
+// writeCGIHeader finalizes the header sent to the client and writes it to the output.
+// p is not written by writeHeader, but is the first chunk of the body
+// that will be written. It is sniffed for a Content-Type if none is
+// set explicitly.
+func (r *response) writeCGIHeader(p []byte) {
+	if r.wroteCGIHeader {
+		return
+	}
+	r.wroteCGIHeader = true
+	fmt.Fprintf(r.bufw, "Status: %d %s\r\n", r.code, http.StatusText(r.code))
 	if _, hasType := r.header["Content-Type"]; !hasType {
-		r.header.Add("Content-Type", "text/html; charset=utf-8")
+		r.header.Set("Content-Type", http.DetectContentType(p))
 	}
-
 	r.header.Write(r.bufw)
 	r.bufw.WriteString("\r\n")
 	r.bufw.Flush()
diff --git a/libgo/go/net/http/cgi/child_test.go b/libgo/go/net/http/cgi/child_test.go
index 14e0af4..f6ecb6e 100644
--- a/libgo/go/net/http/cgi/child_test.go
+++ b/libgo/go/net/http/cgi/child_test.go
@@ -7,6 +7,11 @@
 package cgi
 
 import (
+	"bufio"
+	"bytes"
+	"net/http"
+	"net/http/httptest"
+	"strings"
 	"testing"
 )
 
@@ -148,3 +153,67 @@ func TestRequestWithoutRemotePort(t *testing.T) {
 		t.Errorf("RemoteAddr: got %q; want %q", g, e)
 	}
 }
+
+type countingWriter int
+
+func (c *countingWriter) Write(p []byte) (int, error) {
+	*c += countingWriter(len(p))
+	return len(p), nil
+}
+func (c *countingWriter) WriteString(p string) (int, error) {
+	*c += countingWriter(len(p))
+	return len(p), nil
+}
+
+func TestResponse(t *testing.T) {
+	var tests = []struct {
+		name   string
+		body   string
+		wantCT string
+	}{
+		{
+			name:   "no body",
+			wantCT: "text/plain; charset=utf-8",
+		},
+		{
+			name:   "html",
+			body:   "<html><head><title>test page</title></head><body>This is a body</body></html>",
+			wantCT: "text/html; charset=utf-8",
+		},
+		{
+			name:   "text",
+			body:   strings.Repeat("gopher", 86),
+			wantCT: "text/plain; charset=utf-8",
+		},
+		{
+			name:   "jpg",
+			body:   "\xFF\xD8\xFF" + strings.Repeat("B", 1024),
+			wantCT: "image/jpeg",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			resp := response{
+				req:    httptest.NewRequest("GET", "/", nil),
+				header: http.Header{},
+				bufw:   bufio.NewWriter(&buf),
+			}
+			n, err := resp.Write([]byte(tt.body))
+			if err != nil {
+				t.Errorf("Write: unexpected %v", err)
+			}
+			if want := len(tt.body); n != want {
+				t.Errorf("reported short Write: got %v want %v", n, want)
+			}
+			resp.writeCGIHeader(nil)
+			resp.Flush()
+			if got := resp.Header().Get("Content-Type"); got != tt.wantCT {
+				t.Errorf("wrong content-type: got %q, want %q", got, tt.wantCT)
+			}
+			if !bytes.HasSuffix(buf.Bytes(), []byte(tt.body)) {
+				t.Errorf("body was not correctly written")
+			}
+		})
+	}
+}
diff --git a/libgo/go/net/http/cgi/integration_test.go b/libgo/go/net/http/cgi/integration_test.go
index 32d59c0..295c3b8 100644
--- a/libgo/go/net/http/cgi/integration_test.go
+++ b/libgo/go/net/http/cgi/integration_test.go
@@ -16,7 +16,9 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"os"
+	"strings"
 	"testing"
 	"time"
 )
@@ -52,7 +54,7 @@ func TestHostingOurselves(t *testing.T) {
 	}
 	replay := runCgiTest(t, h, "GET /test.go?foo=bar&a=b HTTP/1.0\nHost: example.com\n\n", expectedMap)
 
-	if expected, got := "text/html; charset=utf-8", replay.Header().Get("Content-Type"); got != expected {
+	if expected, got := "text/plain; charset=utf-8", replay.Header().Get("Content-Type"); got != expected {
 		t.Errorf("got a Content-Type of %q; expected %q", got, expected)
 	}
 	if expected, got := "X-Test-Value", replay.Header().Get("X-Test-Header"); got != expected {
@@ -152,6 +154,51 @@ func TestChildOnlyHeaders(t *testing.T) {
 	}
 }
 
+func TestChildContentType(t *testing.T) {
+	testenv.MustHaveExec(t)
+
+	h := &Handler{
+		Path: os.Args[0],
+		Root: "/test.go",
+		Args: []string{"-test.run=TestBeChildCGIProcess"},
+	}
+	var tests = []struct {
+		name   string
+		body   string
+		wantCT string
+	}{
+		{
+			name:   "no body",
+			wantCT: "text/plain; charset=utf-8",
+		},
+		{
+			name:   "html",
+			body:   "<html><head><title>test page</title></head><body>This is a body</body></html>",
+			wantCT: "text/html; charset=utf-8",
+		},
+		{
+			name:   "text",
+			body:   strings.Repeat("gopher", 86),
+			wantCT: "text/plain; charset=utf-8",
+		},
+		{
+			name:   "jpg",
+			body:   "\xFF\xD8\xFF" + strings.Repeat("B", 1024),
+			wantCT: "image/jpeg",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			expectedMap := map[string]string{"_body": tt.body}
+			req := fmt.Sprintf("GET /test.go?exact-body=%s HTTP/1.0\nHost: example.com\n\n", url.QueryEscape(tt.body))
+			replay := runCgiTest(t, h, req, expectedMap)
+			if got := replay.Header().Get("Content-Type"); got != tt.wantCT {
+				t.Errorf("got a Content-Type of %q; expected it to start with %q", got, tt.wantCT)
+			}
+		})
+	}
+}
+
 // golang.org/issue/7198
 func Test500WithNoHeaders(t *testing.T)     { want500Test(t, "/immediate-disconnect") }
 func Test500WithNoContentType(t *testing.T) { want500Test(t, "/no-content-type") }
@@ -203,6 +250,10 @@ func TestBeChildCGIProcess(t *testing.T) {
 		if req.FormValue("no-body") == "1" {
 			return
 		}
+		if eb, ok := req.Form["exact-body"]; ok {
+			io.WriteString(rw, eb[0])
+			return
+		}
 		if req.FormValue("write-forever") == "1" {
 			io.Copy(rw, neverEnding('a'))
 			for {
diff --git a/libgo/go/net/http/fcgi/child.go b/libgo/go/net/http/fcgi/child.go
index 30a6b2c..a31273b 100644
--- a/libgo/go/net/http/fcgi/child.go
+++ b/libgo/go/net/http/fcgi/child.go
@@ -74,10 +74,12 @@ func (r *request) parseParams() {
 
 // response implements http.ResponseWriter.
 type response struct {
-	req         *request
-	header      http.Header
-	w           *bufWriter
-	wroteHeader bool
+	req            *request
+	header         http.Header
+	code           int
+	wroteHeader    bool
+	wroteCGIHeader bool
+	w              *bufWriter
 }
 
 func newResponse(c *child, req *request) *response {
@@ -92,11 +94,14 @@ func (r *response) Header() http.Header {
 	return r.header
 }
 
-func (r *response) Write(data []byte) (int, error) {
+func (r *response) Write(p []byte) (n int, err error) {
 	if !r.wroteHeader {
 		r.WriteHeader(http.StatusOK)
 	}
-	return r.w.Write(data)
+	if !r.wroteCGIHeader {
+		r.writeCGIHeader(p)
+	}
+	return r.w.Write(p)
 }
 
 func (r *response) WriteHeader(code int) {
@@ -104,22 +109,34 @@ func (r *response) WriteHeader(code int) {
 		return
 	}
 	r.wroteHeader = true
+	r.code = code
 	if code == http.StatusNotModified {
 		// Must not have body.
 		r.header.Del("Content-Type")
 		r.header.Del("Content-Length")
 		r.header.Del("Transfer-Encoding")
-	} else if r.header.Get("Content-Type") == "" {
-		r.header.Set("Content-Type", "text/html; charset=utf-8")
 	}
-
 	if r.header.Get("Date") == "" {
 		r.header.Set("Date", time.Now().UTC().Format(http.TimeFormat))
 	}
+}
 
-	fmt.Fprintf(r.w, "Status: %d %s\r\n", code, http.StatusText(code))
+// writeCGIHeader finalizes the header sent to the client and writes it to the output.
+// p is not written by writeHeader, but is the first chunk of the body
+// that will be written. It is sniffed for a Content-Type if none is
+// set explicitly.
+func (r *response) writeCGIHeader(p []byte) {
+	if r.wroteCGIHeader {
+		return
+	}
+	r.wroteCGIHeader = true
+	fmt.Fprintf(r.w, "Status: %d %s\r\n", r.code, http.StatusText(r.code))
+	if _, hasType := r.header["Content-Type"]; r.code != http.StatusNotModified && !hasType {
+		r.header.Set("Content-Type", http.DetectContentType(p))
+	}
 	r.header.Write(r.w)
 	r.w.WriteString("\r\n")
+	r.w.Flush()
 }
 
 func (r *response) Flush() {
@@ -290,6 +307,8 @@ func (c *child) serveRequest(req *request, body io.ReadCloser) {
 		httpReq = httpReq.WithContext(envVarCtx)
 		c.handler.ServeHTTP(r, httpReq)
 	}
+	// Make sure we serve something even if nothing was written to r
+	r.Write(nil)
 	r.Close()
 	c.mu.Lock()
 	delete(c.requests, req.reqId)
diff --git a/libgo/go/net/http/fcgi/fcgi_test.go b/libgo/go/net/http/fcgi/fcgi_test.go
index e9d2b34..59246c2 100644
--- a/libgo/go/net/http/fcgi/fcgi_test.go
+++ b/libgo/go/net/http/fcgi/fcgi_test.go
@@ -10,6 +10,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net/http"
+	"strings"
 	"testing"
 )
 
@@ -344,3 +345,55 @@ func TestChildServeReadsEnvVars(t *testing.T) {
 		<-done
 	}
 }
+
+func TestResponseWriterSniffsContentType(t *testing.T) {
+	t.Skip("this test is flaky, see Issue 41167")
+	var tests = []struct {
+		name   string
+		body   string
+		wantCT string
+	}{
+		{
+			name:   "no body",
+			wantCT: "text/plain; charset=utf-8",
+		},
+		{
+			name:   "html",
+			body:   "<html><head><title>test page</title></head><body>This is a body</body></html>",
+			wantCT: "text/html; charset=utf-8",
+		},
+		{
+			name:   "text",
+			body:   strings.Repeat("gopher", 86),
+			wantCT: "text/plain; charset=utf-8",
+		},
+		{
+			name:   "jpg",
+			body:   "\xFF\xD8\xFF" + strings.Repeat("B", 1024),
+			wantCT: "image/jpeg",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			input := make([]byte, len(streamFullRequestStdin))
+			copy(input, streamFullRequestStdin)
+			rc := nopWriteCloser{bytes.NewBuffer(input)}
+			done := make(chan bool)
+			var resp *response
+			c := newChild(rc, http.HandlerFunc(func(
+				w http.ResponseWriter,
+				r *http.Request,
+			) {
+				io.WriteString(w, tt.body)
+				resp = w.(*response)
+				done <- true
+			}))
+			defer c.cleanUp()
+			go c.serve()
+			<-done
+			if got := resp.Header().Get("Content-Type"); got != tt.wantCT {
+				t.Errorf("got a Content-Type of %q; expected it to start with %q", got, tt.wantCT)
+			}
+		})
+	}
+}
diff --git a/libgo/go/net/mail/message.go b/libgo/go/net/mail/message.go
index 6833cfa..09fb794 100644
--- a/libgo/go/net/mail/message.go
+++ b/libgo/go/net/mail/message.go
@@ -279,9 +279,6 @@ func (p *addrParser) parseAddressList() ([]*Address, error) {
 		if p.consume(',') {
 			continue
 		}
-		if p.empty() {
-			break
-		}
 
 		addrs, err := p.parseAddress(true)
 		if err != nil {
@@ -295,9 +292,17 @@ func (p *addrParser) parseAddressList() ([]*Address, error) {
 		if p.empty() {
 			break
 		}
-		if !p.consume(',') {
+		if p.peek() != ',' {
 			return nil, errors.New("mail: expected comma")
 		}
+
+		// Skip empty entries for obs-addr-list.
+		for p.consume(',') {
+			p.skipSpace()
+		}
+		if p.empty() {
+			break
+		}
 	}
 	return list, nil
 }
diff --git a/libgo/go/net/mail/message_test.go b/libgo/go/net/mail/message_test.go
index 75db767..67e3643 100644
--- a/libgo/go/net/mail/message_test.go
+++ b/libgo/go/net/mail/message_test.go
@@ -446,6 +446,19 @@ func TestAddressParsing(t *testing.T) {
 			},
 		},
 		{
+			` , joe@where.test,,John <jdoe@one.test>,,`,
+			[]*Address{
+				{
+					Name:    "",
+					Address: "joe@where.test",
+				},
+				{
+					Name:    "John",
+					Address: "jdoe@one.test",
+				},
+			},
+		},
+		{
 			`Group1: <addr1@example.com>;, Group 2: addr2@example.com;, John <addr3@example.com>`,
 			[]*Address{
 				{
@@ -1067,3 +1080,22 @@ func TestAddressFormattingAndParsing(t *testing.T) {
 		}
 	}
 }
+
+func TestEmptyAddress(t *testing.T) {
+	parsed, err := ParseAddress("")
+	if parsed != nil || err == nil {
+		t.Errorf(`ParseAddress("") = %v, %v, want nil, error`, parsed, err)
+	}
+	list, err := ParseAddressList("")
+	if len(list) > 0 || err == nil {
+		t.Errorf(`ParseAddressList("") = %v, %v, want nil, error`, list, err)
+	}
+	list, err = ParseAddressList(",")
+	if len(list) > 0 || err == nil {
+		t.Errorf(`ParseAddressList("") = %v, %v, want nil, error`, list, err)
+	}
+	list, err = ParseAddressList("a@b c@d")
+	if len(list) > 0 || err == nil {
+		t.Errorf(`ParseAddressList("") = %v, %v, want nil, error`, list, err)
+	}
+}
diff --git a/libgo/go/runtime/checkptr_test.go b/libgo/go/runtime/checkptr_test.go
index 76aa2cd..bd2d00f 100644
--- a/libgo/go/runtime/checkptr_test.go
+++ b/libgo/go/runtime/checkptr_test.go
@@ -31,6 +31,7 @@ func TestCheckPtr(t *testing.T) {
 		{"CheckPtrAlignmentPtr", "fatal error: checkptr: misaligned pointer conversion\n"},
 		{"CheckPtrAlignmentNoPtr", ""},
 		{"CheckPtrArithmetic", "fatal error: checkptr: pointer arithmetic result points to invalid allocation\n"},
+		{"CheckPtrArithmetic2", "fatal error: checkptr: pointer arithmetic result points to invalid allocation\n"},
 		{"CheckPtrSize", "fatal error: checkptr: converted pointer straddles multiple allocations\n"},
 		{"CheckPtrSmall", "fatal error: checkptr: pointer arithmetic computed bad pointer value\n"},
 	}
diff --git a/libgo/go/runtime/lockrank_off.go b/libgo/go/runtime/lockrank_off.go
index 425ca8d..32378a9 100644
--- a/libgo/go/runtime/lockrank_off.go
+++ b/libgo/go/runtime/lockrank_off.go
@@ -18,19 +18,29 @@ func getLockRank(l *mutex) lockRank {
 	return 0
 }
 
+// The following functions may be called in nosplit context.
+// Nosplit is not strictly required for lockWithRank, unlockWithRank
+// and lockWithRankMayAcquire, but these nosplit annotations must
+// be kept consistent with the equivalent functions in lockrank_on.go.
+
+//go:nosplit
 func lockWithRank(l *mutex, rank lockRank) {
 	lock2(l)
 }
 
+//go:nosplit
 func acquireLockRank(rank lockRank) {
 }
 
+//go:nosplit
 func unlockWithRank(l *mutex) {
 	unlock2(l)
 }
 
+//go:nosplit
 func releaseLockRank(rank lockRank) {
 }
 
+//go:nosplit
 func lockWithRankMayAcquire(l *mutex, rank lockRank) {
 }
diff --git a/libgo/go/runtime/testdata/testprog/checkptr.go b/libgo/go/runtime/testdata/testprog/checkptr.go
index 45e6fb1..e0a2794 100644
--- a/libgo/go/runtime/testdata/testprog/checkptr.go
+++ b/libgo/go/runtime/testdata/testprog/checkptr.go
@@ -10,6 +10,7 @@ func init() {
 	register("CheckPtrAlignmentNoPtr", CheckPtrAlignmentNoPtr)
 	register("CheckPtrAlignmentPtr", CheckPtrAlignmentPtr)
 	register("CheckPtrArithmetic", CheckPtrArithmetic)
+	register("CheckPtrArithmetic2", CheckPtrArithmetic2)
 	register("CheckPtrSize", CheckPtrSize)
 	register("CheckPtrSmall", CheckPtrSmall)
 }
@@ -32,6 +33,13 @@ func CheckPtrArithmetic() {
 	sink2 = (*int)(unsafe.Pointer(i))
 }
 
+func CheckPtrArithmetic2() {
+	var x [2]int64
+	p := unsafe.Pointer(&x[1])
+	var one uintptr = 1
+	sink2 = unsafe.Pointer(uintptr(p) & ^one)
+}
+
 func CheckPtrSize() {
 	p := new(int64)
 	sink2 = p
diff --git a/libgo/go/sync/map.go b/libgo/go/sync/map.go
index a61e2eb..9ad2535 100644
--- a/libgo/go/sync/map.go
+++ b/libgo/go/sync/map.go
@@ -274,6 +274,7 @@ func (m *Map) LoadAndDelete(key interface{}) (value interface{}, loaded bool) {
 		e, ok = read.m[key]
 		if !ok && read.amended {
 			e, ok = m.dirty[key]
+			delete(m.dirty, key)
 			// Regardless of whether the entry was present, record a miss: this key
 			// will take the slow path until the dirty map is promoted to the read
 			// map.
diff --git a/libgo/go/sync/map_test.go b/libgo/go/sync/map_test.go
index 4ae989a..7f163ca 100644
--- a/libgo/go/sync/map_test.go
+++ b/libgo/go/sync/map_test.go
@@ -9,6 +9,7 @@ import (
 	"reflect"
 	"runtime"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"testing/quick"
 )
@@ -171,3 +172,26 @@ func TestConcurrentRange(t *testing.T) {
 		}
 	}
 }
+
+func TestIssue40999(t *testing.T) {
+	var m sync.Map
+
+	// Since the miss-counting in missLocked (via Delete)
+	// compares the miss count with len(m.dirty),
+	// add an initial entry to bias len(m.dirty) above the miss count.
+	m.Store(nil, struct{}{})
+
+	var finalized uint32
+
+	// Set finalizers that count for collected keys. A non-zero count
+	// indicates that keys have not been leaked.
+	for atomic.LoadUint32(&finalized) == 0 {
+		p := new(int)
+		runtime.SetFinalizer(p, func(*int) {
+			atomic.AddUint32(&finalized, 1)
+		})
+		m.Store(p, struct{}{})
+		m.Delete(p)
+		runtime.GC()
+	}
+}
diff --git a/libgo/go/testing/testing.go b/libgo/go/testing/testing.go
index dee77f7..fe6929d 100644
--- a/libgo/go/testing/testing.go
+++ b/libgo/go/testing/testing.go
@@ -357,10 +357,19 @@ func (p *testPrinter) Fprint(w io.Writer, testName, out string) {
 	defer p.lastNameMu.Unlock()
 
 	if !p.chatty ||
-		strings.HasPrefix(out, "--- PASS") ||
-		strings.HasPrefix(out, "--- FAIL") ||
-		strings.HasPrefix(out, "=== CONT") ||
-		strings.HasPrefix(out, "=== RUN") {
+		strings.HasPrefix(out, "--- PASS: ") ||
+		strings.HasPrefix(out, "--- FAIL: ") ||
+		strings.HasPrefix(out, "--- SKIP: ") ||
+		strings.HasPrefix(out, "=== RUN   ") ||
+		strings.HasPrefix(out, "=== CONT  ") ||
+		strings.HasPrefix(out, "=== PAUSE ") {
+		// If we're buffering test output (!p.chatty), we don't really care which
+		// test is emitting which line so long as they are serialized.
+		//
+		// If the message already implies an association with a specific new test,
+		// we don't need to check what the old test name was or log an extra CONT
+		// line for it. (We're updating it anyway, and the current message already
+		// includes the test name.)
 		p.lastName = testName
 		fmt.Fprint(w, out)
 		return
@@ -887,11 +896,15 @@ func (c *common) Cleanup(f func()) {
 	c.cleanup = func() {
 		if oldCleanup != nil {
 			defer func() {
+				c.mu.Lock()
 				c.cleanupPc = oldCleanupPc
+				c.mu.Unlock()
 				oldCleanup()
 			}()
 		}
+		c.mu.Lock()
 		c.cleanupName = callerName(0)
+		c.mu.Unlock()
 		f()
 	}
 	var pc [maxStackLen]uintptr
@@ -1012,7 +1025,13 @@ func (t *T) Parallel() {
 		for ; root.parent != nil; root = root.parent {
 		}
 		root.mu.Lock()
-		fmt.Fprintf(root.w, "=== PAUSE %s\n", t.name)
+		// Unfortunately, even though PAUSE indicates that the named test is *no
+		// longer* running, cmd/test2json interprets it as changing the active test
+		// for the purpose of log parsing. We could fix cmd/test2json, but that
+		// won't fix existing deployments of third-party tools that already shell
+		// out to older builds of cmd/test2json — so merely fixing cmd/test2json
+		// isn't enough for now.
+		printer.Fprint(root.w, t.name, fmt.Sprintf("=== PAUSE %s\n", t.name))
 		root.mu.Unlock()
 	}