phar: Fix broken return value of fflush() for phar file entries

The flush functions always return EOF, even in the success path.
The success path should return 0 to indicate success.

Closes GH-20474.

NEWS

@@ -21,6 +21,7 @@ PHP                                                                        NEWS
 - Phar:
   . Fixed bug GH-20442 (Phar does not respect case-insensitiveness of
     __halt_compiler() when reading stub). (ndossche, TimWolla)
+  . Fix broken return value of fflush() for phar file entries. (ndossche)
 
 - PHPDBG:
   . Fixed ZPP type violation in phpdbg_get_executable() and phpdbg_end_oplog().

ext/phar/phar.c

@@ -3225,7 +3225,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
 		return EOF;
 	}
 
-	return EOF;
+	return 0;
 
 cleanup:
 	if (shared_cfp != NULL) {

ext/phar/tar.c

@@ -1378,6 +1378,6 @@ nostub:
 			php_stream_close(newfile);
 		}
 	}
-	return EOF;
+	return 0;
 }
 /* }}} */

ext/phar/tests/fflush_phar_file_report_success.phpt

@@ -0,0 +1,25 @@
+--TEST--
+fflush() on phar file should report success
+--EXTENSIONS--
+phar
+--INI--
+phar.readonly=0
+--FILE--
+<?php
+
+$phar = new Phar(__DIR__.'/fflush_phar_file_report_success.phar');
+$phar->addFromString('test', 'contents');
+unset($phar);
+
+$f = fopen('phar://' . __DIR__.'/fflush_phar_file_report_success.phar/test', 'w');
+var_dump(fflush($f));
+var_dump(fclose($f));
+
+?>
+--CLEAN--
+<?php
+@unlink(__DIR__.'/fflush_phar_file_report_success.phar');
+?>
+--EXPECT--
+bool(true)
+bool(true)

ext/phar/zip.c

@@ -1542,6 +1542,6 @@ nocentralerror:
 	if (closeoldfile) {
 		php_stream_close(oldfile);
 	}
-	return EOF;
+	return 0;
 }
 /* }}} */