Limit the Python Poison Pills warning count

PiperOrigin-RevId: 675999156

python/google/protobuf/runtime_version.py

@@ -38,6 +38,9 @@ MINOR = OSS_MINOR
 PATCH = OSS_PATCH
 SUFFIX = OSS_SUFFIX
 
+# Avoid flooding of warnings.
+_MAX_WARNING_COUNT = 20
+_warning_count = 0
 
 class VersionError(Exception):
   """Exception class for version violation."""
@@ -69,6 +72,8 @@ def ValidateProtobufRuntimeVersion(
   if disable_flag is not None and disable_flag.lower() == 'true':
     return
 
+  global _warning_count
+
   version = f'{MAJOR}.{MINOR}.{PATCH}{SUFFIX}'
   gen_version = f'{gen_major}.{gen_minor}.{gen_patch}{gen_suffix}'
 
@@ -89,12 +94,14 @@ def ValidateProtobufRuntimeVersion(
 
   if gen_major != MAJOR:
     if gen_major == MAJOR - 1:
-      warnings.warn(
-          'Protobuf gencode version %s is exactly one major version older than'
-          ' the runtime version %s at %s. Please update the gencode to avoid'
-          ' compatibility violations in the next runtime release.'
-          % (gen_version, version, location)
-      )
+      if _warning_count < _MAX_WARNING_COUNT:
+        warnings.warn(
+            'Protobuf gencode version %s is exactly one major version older'
+            ' than the runtime version %s at %s. Please update the gencode to'
+            ' avoid compatibility violations in the next runtime release.'
+            % (gen_version, version, location)
+        )
+        _warning_count += 1
     else:
       _ReportVersionError(
           'Detected mismatched Protobuf Gencode/Runtime major versions when'
@@ -109,11 +116,13 @@ def ValidateProtobufRuntimeVersion(
         f' cannot be older than the linked gencode version. {error_prompt}'
     )
   elif MINOR > gen_minor or PATCH > gen_patch:
-    warnings.warn(
-        'Protobuf gencode version %s is older than the runtime version %s at'
-        ' %s. Please avoid checked-in Protobuf gencode that can be obsolete.'
-        % (gen_version, version, location)
-    )
+    if _warning_count < _MAX_WARNING_COUNT:
+      warnings.warn(
+          'Protobuf gencode version %s is older than the runtime version %s at'
+          ' %s. Please avoid checked-in Protobuf gencode that can be obsolete.'
+          % (gen_version, version, location)
+      )
+      _warning_count += 1
 
   if gen_suffix != SUFFIX:
     _ReportVersionError(