URL.appendingPathComponent("") crashes

millenomi · millenomi · commit 7972e9b1e015 · 2020-08-25T13:35:49.000-07:00
Do not attempt to read characters from this string if it's empty. 66580574
diff --git a/CoreFoundation/URL.subproj/CFURL.c b/CoreFoundation/URL.subproj/CFURL.c
@@ -4805,7 +4805,7 @@ CFURLRef CFURLCreateCopyAppendingPathComponent(CFAllocatorRef allocator, CFURLRe
                 newComp = CFURLCreateStringByAddingPercentEscapes(allocator, pathComponent, NULL, CFSTR(";?"), url->_encoding);
 #pragma GCC diagnostic pop
             }
-            if ( newComp ) {
+            if ( newComp && CFStringGetLength(newComp) > 0 ) {
                 pathRg = _rangeForComponent(url->_flags, url->_ranges, HAS_PATH);
                 if ( (!pathRg.length || CFStringGetCharacterAtIndex(url->_string, pathRg.location + pathRg.length - 1) != '/') && (CFStringGetCharacterAtIndex(newComp, 0) != '/') ) {
                     CFStringInsert(newString, pathRg.location + pathRg.length, CFSTR("/"));

Original file line number	Diff line number	Diff line change
`@@ -4805,7 +4805,7 @@ CFURLRef CFURLCreateCopyAppendingPathComponent(CFAllocatorRef allocator, CFURLRe`
`4805`	`4805`	`newComp = CFURLCreateStringByAddingPercentEscapes(allocator, pathComponent, NULL, CFSTR(";?"), url->_encoding);`
`4806`	`4806`	`#pragma GCC diagnostic pop`
`4807`	`4807`	`}`
`4808`		`- if ( newComp ) {`
	`4808`	`+ if ( newComp && CFStringGetLength(newComp) > 0 ) {`
`4809`	`4809`	`pathRg = _rangeForComponent(url->_flags, url->_ranges, HAS_PATH);`
`4810`	`4810`	`if ( (!pathRg.length \|\| CFStringGetCharacterAtIndex(url->_string, pathRg.location + pathRg.length - 1) != '/') && (CFStringGetCharacterAtIndex(newComp, 0) != '/') ) {`
`4811`	`4811`	`CFStringInsert(newString, pathRg.location + pathRg.length, CFSTR("/"));`