3.0a6: fix rotating file logger race condition (branched from 3.0a5 as opposed to HEAD due to untested changes on the HEAD).

CHANGES.txt

@@ -1,3 +1,10 @@
+3.0a6
+
+  - The RotatingFileLogger had a race condition in its doRollover
+    method whereby a file might not actually exist despite a call to
+    os.path.exists on the line above a place where we try to remove
+    it.  We catch the exception now and ignore the missing file.
+
 3.0a5
 
   - Supervisorctl now supports persistent readline history.  To

src/supervisor/loggers.py

@@ -210,11 +210,21 @@ class RotatingFileHandler(FileHandler):
                 dfn = "%s.%d" % (self.baseFilename, i + 1)
                 if os.path.exists(sfn):
                     if os.path.exists(dfn):
-                        os.remove(dfn)
+                        try:
+                            os.remove(dfn)
+                        except OSError, why:
+                            # catch race condition (already deleted)
+                            if why[0] != errno.ENOENT:
+                                raise
                     os.rename(sfn, dfn)
             dfn = self.baseFilename + ".1"
             if os.path.exists(dfn):
-                os.remove(dfn)
+                try:
+                    os.remove(dfn)
+                except OSError, why:
+                    # catch race condition (already deleted)
+                    if why[0] != errno.ENOENT:
+                        raise
             os.rename(self.baseFilename, dfn)
         self.stream = open(self.baseFilename, 'w')
 

src/supervisor/version.txt

@@ -1,2 +1,2 @@
-3.0a5
+3.0a6