Merge NSLock candidate fix

Source/NSLock.m

@@ -36,12 +36,14 @@
 #import "GSPrivate.h"
 #import "GSPThread.h"
 #include <math.h>
+#include <stdlib.h>
 
 #import "common.h"
 
 #import "Foundation/NSLock.h"
 #import "Foundation/NSException.h"
 #import "Foundation/NSThread.h"
+// #import "Foundation/NSUserDefaults.h"
 
 #define class_createInstance(C,E) NSAllocateObject(C,E,NSDefaultMallocZone())
 
@@ -247,7 +249,16 @@ - (void) unlock\
 {\
   if (0 != GS_MUTEX_UNLOCK(_mutex))\
     {\
-      NSLog(@"failed to unlock mutex");\
+      if (GSPrivateDefaultsFlag(GSMacOSXCompatible))\
+	{\
+          NSLog(@"Failed to unlock mutex %@ at %@",\
+	    self, [NSThread callStackSymbols]);\
+	}\
+      else \
+	{\
+          [NSException raise: NSLockException\
+		      format: @"failed to unlock mutex %@", self];\
+	}\
     }\
   CHK(Drop) \
 }

Tests/base/NSLock/unbalancedUnlock.m

@@ -0,0 +1,25 @@
+#import <Foundation/Foundation.h>
+#import "Testing.h"
+#import "ObjectTesting.h"
+
+int main()
+{
+  START_SET("Unbalanced unlocking")
+
+  NSLock		*lock = [NSLock new];
+  NSUserDefaults	*defs = [NSUserDefaults standardUserDefaults];
+  BOOL			mode = [defs boolForKey: @"GSMacOSXCompatible"]; 
+
+  [defs setBool: NO forKey: @"GSMacOSXCompatible"];
+  PASS_EXCEPTION([lock unlock], @"NSLockException",
+    "unlocking an unlocked lock raises NSLockException")
+
+  [defs setBool: YES forKey: @"GSMacOSXCompatible"];
+  PASS_RUNS([lock unlock],
+    "unlocking an unlocked lock does not raise in MacOSX compatibility mode")
+
+  [defs setBool: mode forKey: @"GSMacOSXCompatible"];
+
+  END_SET("Unbalanced unlocking")
+  return 0;
+}