Rev 3432: Disable suppression if there is already a filter present for Warnings in http://bzr.arbash-meinel.com/branches/bzr/1.6-dev/dep_warnings

[John Arbash Meinel]

At http://bzr.arbash-meinel.com/branches/bzr/1.6-dev/dep_warnings

------------------------------------------------------------
revno: 3432
revision-id: john at arbash-meinel.com-20080528230834-m1qw9peoydd3koty
parent: john at arbash-meinel.com-20080528215346-l8plys9h9ps624pn
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: dep_warnings
timestamp: Wed 2008-05-28 18:08:34 -0500
message:
  Disable suppression if there is already a filter present for Warnings
modified:
  bzrlib/symbol_versioning.py    symbol_versioning.py-20060105104851-9ecf8af605d15a80
  bzrlib/tests/test_symbol_versioning.py test_symbol_versioning.py-20060105104851-51d7722c2018d42b
-------------- next part --------------
=== modified file 'bzrlib/symbol_versioning.py'
--- a/bzrlib/symbol_versioning.py	2008-05-28 21:53:46 +0000
+++ b/bzrlib/symbol_versioning.py	2008-05-28 23:08:34 +0000
@@ -333,6 +333,21 @@
     return _DeprecatedList(initial_value)
 
 
+def _check_for_filter(error_only):
+    """Check if there is already a filter for deprecation warnings.
+    
+    :param error_only: Only match an 'error' filter
+    :return: True if a filter is found, False otherwise
+    """
+    import warnings
+    for filter in warnings.filters:
+        if issubclass(DeprecationWarning, filter[2]):
+            # This filter will effect DeprecationWarning
+            if not error_only or filter[0] == 'error':
+                return True
+    return False
+
+
 def suppress_deprecation_warnings():
     """Call this function to suppress all deprecation warnings.
 
@@ -341,6 +356,10 @@
     running a dev or release candidate.
     """
     import warnings
+    if _check_for_filter(False):
+        # If there is already a filter effecting suppress_deprecation_warnings,
+        # then skip it.
+        return
     warnings.filterwarnings('ignore', category=DeprecationWarning)
 
 
@@ -359,11 +378,8 @@
         to be turned into errors. If True, then do not override with 'default'.
     """
     import warnings
-    if not always:
-        for filter in warnings.filters:
-            if (filter[0] == 'error'
-                and issubclass(DeprecationWarning, filter[2])):
-                # DeprecationWarnings are already turned into errors, don't
-                # downgrade them to 'default'.
-                return
+    if not always and _check_for_filter(True):
+        # DeprecationWarnings are already turned into errors, don't downgrade
+        # them to 'default'.
+        return
     warnings.filterwarnings('default', category=DeprecationWarning)

=== modified file 'bzrlib/tests/test_symbol_versioning.py'
--- a/bzrlib/tests/test_symbol_versioning.py	2008-05-28 21:44:15 +0000
+++ b/bzrlib/tests/test_symbol_versioning.py	2008-05-28 23:08:34 +0000
@@ -218,6 +218,8 @@
         def restore():
             warnings.filters[:] = existing_filters
         self.addCleanup(restore)
+        # Clean out the filters so we have a clean slate.
+        warnings.resetwarnings()
 
     def assertFirstWarning(self, action, category):
         """Test the first warning in the filters is correct"""
@@ -229,19 +231,35 @@
         symbol_versioning.suppress_deprecation_warnings()
         self.assertFirstWarning('ignore', DeprecationWarning)
 
+    def test_suppress_deprecation_with_warning_filter(self):
+        """don't suppress if we already have a filter"""
+        warnings.filterwarnings('ignore', category=Warning)
+        self.assertFirstWarning('ignore', Warning)
+        self.assertEqual(1, len(warnings.filters))
+        symbol_versioning.suppress_deprecation_warnings()
+        self.assertFirstWarning('ignore', Warning)
+        self.assertEqual(1, len(warnings.filters))
+
+    def test_suppress_deprecation_with_filter(self):
+        """don't suppress if we already have a filter"""
+        warnings.filterwarnings('ignore', category=DeprecationWarning)
+        self.assertFirstWarning('ignore', DeprecationWarning)
+        self.assertEqual(1, len(warnings.filters))
+        symbol_versioning.suppress_deprecation_warnings()
+        self.assertFirstWarning('ignore', DeprecationWarning)
+        self.assertEqual(1, len(warnings.filters))
+
     def test_activate_deprecation_warnings(self):
         symbol_versioning.activate_deprecation_warnings(always=True)
         self.assertFirstWarning('default', DeprecationWarning)
 
     def test_activate_deprecation_no_error(self):
         # First nuke the filters, so we know it is clean
-        warnings.resetwarnings()
         symbol_versioning.activate_deprecation_warnings(always=False)
         self.assertFirstWarning('default', DeprecationWarning)
 
     def test_activate_deprecation_with_error(self):
         # First nuke the filters, so we know it is clean
-        warnings.resetwarnings()
         # Add a warning == error rule
         warnings.filterwarnings('error', category=Warning)
         self.assertFirstWarning('error', Warning)
@@ -253,7 +271,6 @@
 
     def test_activate_deprecation_with_DW_error(self):
         # First nuke the filters, so we know it is clean
-        warnings.resetwarnings()
         # Add a warning == error rule
         warnings.filterwarnings('error', category=DeprecationWarning)
         self.assertFirstWarning('error', DeprecationWarning)