Fix broken git-style patch behavior

When a git-syle patch is applied, all file modifications are done to
temporary files which are put in place when the patch ends.  When a
patch fails, GNU patch was trying to "roll back" to the start.  A bug in
that code that lead to accidental file deletion was recently discovered
by Richard Weinberger <richard@nod.at>.  Even worse though, GNU patch
should not exhibit this "rollback" behavior in the first place; that's
not what people expect. Instead, the files modified so far should be put
in place.
* src/patch.c (cleanup): Put output files processed successfully
in place instead of trying to "roll back" to the start.
(forget_output_files): Remove obsolete (and broken) function.
* tests/git-cleanup: New broken git-style patch test case that exercises
the cleanup path.
* tests/Makefile.am (TESTS): Add new test case.

1 files changed, 1 insertions, 17 deletions

diff --git a/src/patch.c b/src/patch.c
index b0ed91a..bf7e5c2 100644
--- a/src/patch.c
+++ b/src/patch.c
@@ -1966,22 +1966,6 @@ output_files (struct stat const *st)
   gl_list_clear (files_to_output);
 }
 
-static void
-forget_output_files (void)
-{
-  gl_list_iterator_t iter = gl_list_iterator (files_to_output);
-  const void *elt;
-
-  while (gl_list_iterator_next (&iter, &elt, NULL))
-    {
-      const struct file_to_output *file_to_output = elt;
-
-      safe_unlink (file_to_output->from);
-    }
-  gl_list_iterator_free (&iter);
-  gl_list_clear (files_to_output);
-}
-
 /* Fatal exit with cleanup. */
 
 void
@@ -2012,5 +1996,5 @@ cleanup (void)
   remove_if_needed (TMPOUTNAME, &TMPOUTNAME_needs_removal);
   remove_if_needed (TMPPATNAME, &TMPPATNAME_needs_removal);
   remove_if_needed (TMPREJNAME, &TMPREJNAME_needs_removal);
-  forget_output_files ();
+  output_files (NULL);
 }