gh-139640: Fix swallowing syntax warnings in different modules (GH-139755)

Revert GH-131993.

Fix swallowing some syntax warnings in different modules if they accidentally
have the same message and are emitted from the same line.

Python/_warnings.c

@@ -1473,28 +1473,6 @@ PyErr_WarnExplicitObject(PyObject *category, PyObject *message,
     return 0;
 }
 
-/* Like PyErr_WarnExplicitObject, but automatically sets up context */
-int
-_PyErr_WarnExplicitObjectWithContext(PyObject *category, PyObject *message,
-                                     PyObject *filename, int lineno)
-{
-    PyObject *unused_filename, *module, *registry;
-    int unused_lineno;
-    int stack_level = 1;
-
-    if (!setup_context(stack_level, NULL, &unused_filename, &unused_lineno,
-                       &module, &registry)) {
-        return -1;
-    }
-
-    int rc = PyErr_WarnExplicitObject(category, message, filename, lineno,
-                                      module, registry);
-    Py_DECREF(unused_filename);
-    Py_DECREF(registry);
-    Py_DECREF(module);
-    return rc;
-}
-
 int
 PyErr_WarnExplicit(PyObject *category, const char *text,
                    const char *filename_str, int lineno,

Python/compile.c

@@ -103,6 +103,7 @@ typedef struct _PyCompiler {
     bool c_save_nested_seqs;     /* if true, construct recursive instruction sequences
                                   * (including instructions for nested code objects)
                                   */
+    int c_disable_warning;
 } compiler;
 
 static int
@@ -765,6 +766,9 @@ _PyCompile_PushFBlock(compiler *c, location loc,
     f->fb_loc = loc;
     f->fb_exit = exit;
     f->fb_datum = datum;
+    if (t == COMPILE_FBLOCK_FINALLY_END) {
+        c->c_disable_warning++;
+    }
     return SUCCESS;
 }
 
@@ -776,6 +780,9 @@ _PyCompile_PopFBlock(compiler *c, fblocktype t, jump_target_label block_label)
     u->u_nfblocks--;
     assert(u->u_fblock[u->u_nfblocks].fb_type == t);
     assert(SAME_JUMP_TARGET_LABEL(u->u_fblock[u->u_nfblocks].fb_block, block_label));
+    if (t == COMPILE_FBLOCK_FINALLY_END) {
+        c->c_disable_warning--;
+    }
 }
 
 fblockinfo *
@@ -1203,6 +1210,9 @@ _PyCompile_Error(compiler *c, location loc, const char *format, ...)
 int
 _PyCompile_Warn(compiler *c, location loc, const char *format, ...)
 {
+    if (c->c_disable_warning) {
+        return 0;
+    }
     va_list vargs;
     va_start(vargs, format);
     PyObject *msg = PyUnicode_FromFormatV(format, vargs);

Python/errors.c

@@ -1962,8 +1962,8 @@ int
 _PyErr_EmitSyntaxWarning(PyObject *msg, PyObject *filename, int lineno, int col_offset,
                          int end_lineno, int end_col_offset)
 {
-    if (_PyErr_WarnExplicitObjectWithContext(PyExc_SyntaxWarning, msg,
-                                             filename, lineno) < 0)
+    if (PyErr_WarnExplicitObject(PyExc_SyntaxWarning, msg,
+                                 filename, lineno, NULL, NULL) < 0)
     {
         if (PyErr_ExceptionMatches(PyExc_SyntaxWarning)) {
             /* Replace the SyntaxWarning exception with a SyntaxError