backport small fixes

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/branches/stable@33223 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,10 @@
+2011-06-01  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Headers/Foundation/NSString.h: Add explicit warnings about OSX
+	compatible modifications to values returned by path methods.
+	* Source/NSTimeZone.m: Don't guess at tzname[0] if the value of
+	daylight shows it's not valid.
+
 2011-05-28  Fred Kiefer <FredKiefer@gmx.de>
 
 	* Source/NSString.m (-initWithFormat:locale:): Make sure va_end()

Headers/Foundation/NSString.h

@@ -550,6 +550,10 @@ typedef NSUInteger NSStringEncodingConversionOptions;
  *   @"/" with @"/file" produces @"/file"
  *   @"path with @"C:/file" produces @"path/file"
  * </example>
+ * NB. Do not use this method to modify strings other than filesystem
+ * paths as the behavior in such cases is undefined ... for instance
+ * the string may have repeated slashes or slash-dot-slash sequences
+ * removed.
  */
 - (NSString*) stringByAppendingPathComponent: (NSString*)aString;
 
@@ -571,6 +575,10 @@ typedef NSUInteger NSStringEncodingConversionOptions;
  *   @"/" with @"app" produces @"/" (no file name to append to)
  *   @"" with @"app" produces @"" (no file name to append to)
  * </example>
+ * NB. Do not use this method to modify strings other than filesystem
+ * paths as the behavior in such cases is undefined ... for instance
+ * the string may have repeated slashes or slash-dot-slash sequences
+ * removed.
  */
 - (NSString*) stringByAppendingPathExtension: (NSString*)aString;
 
@@ -593,6 +601,10 @@ typedef NSUInteger NSStringEncodingConversionOptions;
  *   @"//host/share/" produces @"//host/share/" (a UNC path)
  *   @"//path/file" produces @"//path" (an absolute Unix path)
  * </example>
+ * NB. Do not use this method to modify strings other than filesystem
+ * paths as the behavior in such cases is undefined ... for instance
+ * the string may have repeated slashes or slash-dot-slash sequences
+ * removed.
  */
 - (NSString*) stringByDeletingLastPathComponent;
 
@@ -613,6 +625,10 @@ typedef NSUInteger NSStringEncodingConversionOptions;
  *   @"/.ext" produces @"/.ext" (there is no file to strip from)
  *   @".ext" produces @".ext" (there is no file to strip from)
  * </example>
+ * NB. Do not use this method to modify strings other than filesystem
+ * paths as the behavior in such cases is undefined ... for instance
+ * the string may have repeated slashes or slash-dot-slash sequences
+ * removed.
  */
 - (NSString*) stringByDeletingPathExtension;
 

Source/NSTimeZone.m

@@ -1526,13 +1526,16 @@ static NSMapTable	*absolutes = 0;
         }
 #if HAVE_TZSET
       /*
-       * Try to get timezone from tzset and tzname
+       * Try to get timezone from tzset and tzname/daylight.
+       * If daylight is non-zero, then tzname[0] is only the name
+       * the the zone for part of the year, so we can't use it as
+       * the definitive zone.
        */
       if (localZoneString == nil)
 	{
           localZoneSource = @"function: 'tzset()/tzname'";
 	  tzset();
-	  if (tzname[0] != NULL && *tzname[0] != '\0')
+	  if (NULL != tzname[0] && '\0' != *tzname[0] && 0 == daylight)
 	    localZoneString = [NSString stringWithUTF8String: tzname[0]];
 	}
 #endif