[gdb/python] Handle empty PYTHONDONTWRITEBYTECODE

When using PYTHONDONTWRITEBYTECODE with an empty string we get:
...
$ PYTHONDONTWRITEBYTECODE= gdb -q -batch -ex "show python dont-write-bytecode"
Python's dont-write-bytecode setting is auto (currently on).
...

This is incorrect, it should be off.

The actual setting is correct, that was already fixed in commit 24d2cbc42cc
("set/show python dont-write-bytecode fixes"), in function
python_write_bytecode.

Fix this by:
- factoring out new function env_python_dont_write_bytecode out of
  python_write_bytecode, and
- using it in show_python_dont_write_bytecode.

Tested on x86_64-linux, using test-case gdb.python/py-startup-opt.exp and:
- PYTHONDONTWRITEBYTECODE=
- PYTHONDONTWRITEBYTECODE=1
- unset PYTHONDONTWRITEBYTECODE

Approved-By: Tom Tromey <tom@tromey.com>

PR python/32389
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32389

1 files changed, 8 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.python/py-startup-opt.exp b/gdb/testsuite/gdb.python/py-startup-opt.exp
index 014aff5..df35a37 100644
--- a/gdb/testsuite/gdb.python/py-startup-opt.exp
+++ b/gdb/testsuite/gdb.python/py-startup-opt.exp
@@ -93,6 +93,14 @@ proc test_python_settings { exp_state } {
 	    "else:" "" \
 	    "  print (\"${attr} is off\")" "" \
 	    "end" "${attr} is ${answer}"
+
+	if { $attr == "dont_write_bytecode" && $exp_state == "off" } {
+	    set setting dont-write-bytecode
+	    set show_setting \
+		"Python's $setting setting is auto (currently $answer)."
+	    gdb_test "show python $setting" \
+		[string_to_regexp $show_setting]
+	}
     }
 
     gdb_exit