[binutils-gdb] [gdb/dap] Fix dap for python < 3.8

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=fc21e0f029c51687c2b4ca686d0b773ad5efeff4

commit fc21e0f029c51687c2b4ca686d0b773ad5efeff4
Author: Tom de Vries <tdevries@suse.de>
Date:   Tue Sep 26 15:51:27 2023 +0200

    [gdb/dap] Fix dap for python < 3.8
    
    With any gdb.dap test and python 3.6 I run into:
    ...
    Error occurred in Python: 'code' object has no attribute 'co_posonlyargcount'
    ERROR: eof reading json header
    ...
    
    The attribute is not supported before python 3.8, which introduced the
    "Positional−only Parameters" concept.
    
    Fix this by using try/except AttributeError.
    
    Tested on x86_64-linux:
    - openSUSE Leap 15.4 with python 3.6, and
    - openSUSE Tumbleweed with python 3.11.5.
    
    Approved-By: Tom Tromey <tom@tromey.com>

Diff:
---
 gdb/python/lib/gdb/dap/server.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gdb/python/lib/gdb/dap/server.py b/gdb/python/lib/gdb/dap/server.py
index d84bca5d1fc..62bf240c1e9 100644
--- a/gdb/python/lib/gdb/dap/server.py
+++ b/gdb/python/lib/gdb/dap/server.py
@@ -168,7 +168,11 @@ def request(name):
         global _commands
         code = func.__code__
         # We don't permit requests to have positional arguments.
-        assert code.co_posonlyargcount == 0
+        try:
+            assert code.co_posonlyargcount == 0
+        except AttributeError:
+            # Attribute co_posonlyargcount is supported starting python 3.8.
+            pass
         assert code.co_argcount == 0
         # A request must have a **args parameter.
         assert code.co_flags & inspect.CO_VARKEYWORDS