[llvm][vfs] Avoid silent fallback to process-wide working directory

In createPhysicalFileSystem, preserve the per-instance working
directory, even after the first call to getcwd fails.

rdar://108213753

Differential Revision: https://reviews.llvm.org/D149173

1 files changed, 26 insertions, 0 deletions

diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
index d31674a..cfbb81e 100644
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/VirtualFileSystem.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -526,6 +527,31 @@ TEST(VirtualFileSystemTest, MultipleWorkingDirs) {
   ASSERT_EQ(CIt, vfs::directory_iterator());
 }
 
+TEST(VirtualFileSystemTest, PhysicalFileSystemWorkingDirFailure) {
+  TempDir D2("d2", /*Unique*/ true);
+  SmallString<128> WD, PrevWD;
+  ASSERT_EQ(sys::fs::current_path(PrevWD), std::error_code());
+  ASSERT_EQ(sys::fs::createUniqueDirectory("d1", WD), std::error_code());
+  ASSERT_EQ(sys::fs::set_current_path(WD), std::error_code());
+  auto Restore =
+      llvm::make_scope_exit([&] { sys::fs::set_current_path(PrevWD); });
+
+  // Delete the working directory to create an error.
+  ASSERT_EQ(sys::fs::remove_directories(WD), std::error_code());
+
+  // Verify that we still get two separate working directories.
+  auto FS1 = vfs::createPhysicalFileSystem();
+  auto FS2 = vfs::createPhysicalFileSystem();
+  ASSERT_EQ(FS1->getCurrentWorkingDirectory().getError(),
+            errc::no_such_file_or_directory);
+  ASSERT_EQ(FS1->setCurrentWorkingDirectory(D2.path()), std::error_code());
+  ASSERT_EQ(FS1->getCurrentWorkingDirectory().get(), D2.path());
+  EXPECT_EQ(FS2->getCurrentWorkingDirectory().getError(),
+            errc::no_such_file_or_directory);
+  SmallString<128> WD2;
+  EXPECT_EQ(sys::fs::current_path(WD2), errc::no_such_file_or_directory);
+}
+
 TEST(VirtualFileSystemTest, BrokenSymlinkRealFSIteration) {
   TempDir TestDirectory("virtual-file-system-test", /*Unique*/ true);
   IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getRealFileSystem();