[binutils-gdb] [gdb/python] Avoid queue.SimpleQueue for python 3.6

[binutils-gdb] [gdb/python] Avoid queue.SimpleQueue for python 3.6

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=954a1f9183c68671c07f21baf78ac2053390af55

commit 954a1f9183c68671c07f21baf78ac2053390af55
Author: Tom de Vries <tdevries@suse.de>
Date:   Thu Jan 5 17:35:41 2023 +0100

    [gdb/python] Avoid queue.SimpleQueue for python 3.6
    
    On openSUSE Leap 15.4 with python 3.6, the gdb.dap/basic-dap.exp test-case
    fails as follows:
    ...
    ERROR: eof reading json header
        while executing
    "error "eof reading json header""
        invoked from within
    "expect {
    -i exp19 -timeout 10
            -re "^Content-Length: (\[0-9\]+)\r\n" {
                set length $expect_out(1,string)
                exp_continue
            }
            -re "^(\[^\r\n\]+)..."
        ("uplevel" body line 1)
        invoked from within
    "uplevel $body" NONE eof reading json header
    UNRESOLVED: gdb.dap/basic-dap.exp: startup - initialize
    ...
    
    Investigation using a "catch throw" shows that:
    ...
    (gdb)
        at gdb/python/py-utils.c:396
    396             error (_("Error occurred in Python: %s"), msg.get ());
    (gdb) p msg.get ()
    $1 = 0x2b91d10 "module 'queue' has no attribute 'SimpleQueue'"
    ...
    
    The python class queue.SimpleQueue was introduced in python 3.7.
    
    Fix this by falling back to queue.Queue for python <= 3.6.
    
    Tested on x86_64-linux, by successfully running the test-case:
    ...
     # of expected passes            47
    ...

Diff:
---
 gdb/python/lib/gdb/dap/server.py  | 6 +++++-
 gdb/python/lib/gdb/dap/startup.py | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/gdb/python/lib/gdb/dap/server.py b/gdb/python/lib/gdb/dap/server.py
index d6fc0bd5754..f8cb6170a96 100644
--- a/gdb/python/lib/gdb/dap/server.py
+++ b/gdb/python/lib/gdb/dap/server.py
@@ -15,6 +15,7 @@
 
 import json
 import queue
+import sys
 
 from .io import start_json_writer, read_json
 from .startup import (
@@ -47,7 +48,10 @@ class Server:
         # This queue accepts JSON objects that are then sent to the
         # DAP client.  Writing is done in a separate thread to avoid
         # blocking the read loop.
-        self.write_queue = queue.SimpleQueue()
+        if sys.version_info[0] == 3 and sys.version_info[1] <= 6:
+            self.write_queue = queue.Queue()
+        else:
+            self.write_queue = queue.SimpleQueue()
         self.done = False
         global _server
         _server = self
diff --git a/gdb/python/lib/gdb/dap/startup.py b/gdb/python/lib/gdb/dap/startup.py
index acfdcb4d81b..523705a5933 100644
--- a/gdb/python/lib/gdb/dap/startup.py
+++ b/gdb/python/lib/gdb/dap/startup.py
@@ -22,6 +22,7 @@ import signal
 import threading
 import traceback
 from contextlib import contextmanager
+import sys
 
 
 # The GDB thread, aka the main thread.
@@ -173,7 +174,10 @@ def send_gdb_with_response(fn):
     """
     if isinstance(fn, str):
         fn = Invoker(fn)
-    result_q = queue.SimpleQueue()
+    if sys.version_info[0] == 3 and sys.version_info[1] <= 6:
+        result_q = queue.Queue()
+    else:
+        result_q = queue.SimpleQueue()
 
     def message():
         try: