- [DOC] Changed stream_get_contents() so that the offset is relative to the

  current position (seek with SEEK_CUR, not SEEK_SET). Only positive values are
  allowed. This breaking change is necessary to fix the erratic behavior in
  streams without a seek handlder. Addresses bug #53006.
#Note that the example on the doc page for stream_get_contents() may fail
#without this change.
#This change is also in the spirit of stream_get_contents(), whose description
#is "Reads all remaining bytes (or up to maxlen bytes) from a stream...".
#Previous behavior allowed setting the file pointer to positions before the
#current one, so they wouldn't be "remaining bytes". The previous behavior was
#also inconsistent in that it allowed an moving to offset 1, 2, ..., but not 0.

Author: cataphract

ext/standard/streamsfuncs.c

@@ -425,8 +425,11 @@ PHP_FUNCTION(stream_get_contents)
 
 	php_stream_from_zval(stream, &zsrc);
 
-	if ((pos > 0 || (pos == 0 && ZEND_NUM_ARGS() > 2)) && php_stream_seek(stream, pos, SEEK_SET) < 0) {
-		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Failed to seek to position %ld in the stream", pos);
+	if ((pos != 0L) && php_stream_seek(stream, pos, SEEK_CUR) < 0) {
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Failed to seek %ld bytes from current position in the stream", pos);
+		RETURN_FALSE;
+	} else if (pos < 0L) {
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Number of bytes to seek must be non-negative, given %ld", pos);
 		RETURN_FALSE;
 	}