[binutils-gdb] [gdb/python] Normalize exceptions in gdbpy_err_fetch

[binutils-gdb] [gdb/python] Normalize exceptions in gdbpy_err_fetch

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=50ede76876981364d6b1a314bb79c0412980c435

commit 50ede76876981364d6b1a314bb79c0412980c435
Author: Tom de Vries <tdevries@suse.de>
Date:   Sat Mar 9 16:13:10 2024 +0100

    [gdb/python] Normalize exceptions in gdbpy_err_fetch
    
    With python 3.12, I run into:
    ...
    (gdb) PASS: gdb.python/py-block.exp: check variable access
    python print (block['nonexistent'])^M
    Python Exception <class 'KeyError'>: 'nonexistent'^M
    Error occurred in Python: 'nonexistent'^M
    (gdb) FAIL: gdb.python/py-block.exp: check nonexistent variable
    ...
    
    The problem is that that PyErr_Fetch returns a normalized exception, while the
    test-case matches the output for an unnormalized exception.
    
    With python 3.6, PyErr_Fetch returns an unnormalized exception, and the
    test passes.
    
    Fix this by:
    - updating the test-case to match the output for a normalized exception, and
    - lazily forcing normalized exceptions using PyErr_NormalizeException.
    
    Tested on aarch64-linux.
    
    Approved-By: Tom Tromey <tom@tromey.com>

Diff:
---
 gdb/python/python-internal.h          | 15 ++++++++++++++-
 gdb/testsuite/gdb.python/py-block.exp |  2 +-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 9ceb4aa7ed4..30802ae2480 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -683,6 +683,18 @@ public:
 
   gdbpy_ref<> value () const
   {
+    if (!m_normalized)
+      {
+	PyObject *error_type, *error_value, *error_traceback;
+	error_type = m_error_type.release ();
+	error_value = m_error_value.release ();
+	error_traceback = m_error_traceback.release ();
+	PyErr_NormalizeException (&error_type, &error_value, &error_traceback);
+	m_error_type.reset (error_type);
+	m_error_value.reset (error_value);
+	m_error_traceback.reset (error_traceback);
+	m_normalized = true;
+      }
     return m_error_value;
   }
 
@@ -695,7 +707,8 @@ public:
 
 private:
 
-  gdbpy_ref<> m_error_type, m_error_value, m_error_traceback;
+  mutable gdbpy_ref<> m_error_type, m_error_value, m_error_traceback;
+  mutable bool m_normalized = false;
 };
 
 /* Called before entering the Python interpreter to install the
diff --git a/gdb/testsuite/gdb.python/py-block.exp b/gdb/testsuite/gdb.python/py-block.exp
index 942611af305..99642a546a7 100644
--- a/gdb/testsuite/gdb.python/py-block.exp
+++ b/gdb/testsuite/gdb.python/py-block.exp
@@ -44,7 +44,7 @@ gdb_test "python print (block.function)" "None" "first anonymous block"
 gdb_test "python print (block.start)" "${decimal}" "check start not None"
 gdb_test "python print (block.end)" "${decimal}" "check end not None"
 gdb_test "python print (block\['f'\].name == 'f')" "True" "check variable access"
-gdb_test "python print (block\['nonexistent'\])" ".*KeyError.*: nonexistent.*" \
+gdb_test "python print (block\['nonexistent'\])" ".*KeyError.*: 'nonexistent'.*" \
          "check nonexistent variable"
 gdb_test "python print (block\[42\])" ".*TypeError.*: Expected a string.*" \
          "check non-string key"