Backport for Gentoo patch-2.7.x.

https://bugs.gentoo.org/664640


Original patch:
Author: Lubomir Rintel <lkundrak@v3.sk>
Date:   Tue Feb 27 16:52:00 2018 +0100
Subject: Fix error handling with git-style patches

When an error is encountered in output_files(), the subsequent call to
cleanup() calls back into output_files() resulting in an infinte recursion.
This is trivially reproduced with a git-style patch (which utilizes
output_file_later()) that tries to patch a nonexistent or unreadable
file (see attached test case).

* src/patch.c: (output_files) clear the files_to_output list before
iterating it, so that recursive calls won't iterate the same files.
* tests/git-error: New test case.
* tests/Makefile.am (TESTS): Add test case.

Origin: https://lists.gnu.org/archive/html/bug-patch/2018-02/msg00010.html

--- a/src/patch.c
+++ b/src/patch.c
@@ -1938,8 +1938,12 @@ output_files (struct stat const *st)
 {
   gl_list_iterator_t iter;
   const void *elt;
+  gl_list_t files;
 
-  iter = gl_list_iterator (files_to_output);
+  files = files_to_output;
+  init_files_to_output ();
+
+  iter = gl_list_iterator (files);
   while (gl_list_iterator_next (&iter, &elt, NULL))
     {
       const struct file_to_output *file_to_output = elt;
@@ -1957,8 +1961,8 @@ output_files (struct stat const *st)
 	  /* Free the list up to here. */
 	  for (;;)
 	    {
-	      const void *elt2 = gl_list_get_at (files_to_output, 0);
-	      gl_list_remove_at (files_to_output, 0);
+	      const void *elt2 = gl_list_get_at (files, 0);
+	      gl_list_remove_at (files, 0);
 	      if (elt == elt2)
 		break;
 	    }
@@ -1967,7 +1971,7 @@ output_files (struct stat const *st)
 	}
     }
   gl_list_iterator_free (&iter);
-  gl_list_clear (files_to_output);
+  gl_list_free (files);
 }
 
 /* Fatal exit with cleanup. */
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -40,6 +40,7 @@ TESTS = \
 	filename-choice \
 	git-binary-diff \
 	git-cleanup \
+	git-error \
 	garbage \
 	global-reject-files \
 	inname \
--- a/tests/Makefile.in
+++ b/tests/Makefile.in
@@ -1316,6 +1316,7 @@ TESTS = \
 	filename-choice \
 	git-binary-diff \
 	git-cleanup \
+	git-error \
 	garbage \
 	global-reject-files \
 	inname \
@@ -1695,6 +1696,13 @@ git-cleanup.log: git-cleanup
 	--log-file $$b.log --trs-file $$b.trs \
 	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
 	"$$tst" $(AM_TESTS_FD_REDIRECT)
+git-error.log: git-error
+	@p='git-error'; \
+	b='git-error'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
 garbage.log: garbage
 	@p='garbage'; \
 	b='garbage'; \
--- /dev/null
+++ b/tests/git-error
@@ -0,0 +1,29 @@
+# Copyright (C) 2018 Free Software Foundation, Inc.
+#
+# Copying and distribution of this file, with or without modification,
+# in any medium, are permitted without royalty provided the copyright
+# notice and this notice are preserved.
+
+. $srcdir/test-lib.sh
+
+require cat
+use_local_patch
+use_tmpdir
+
+cat > f.diff <<EOF
+diff --git a/boo b/boo
+--- /dev/fd/63 2018-02-27 16:32:54.861266246 +0100
++++ /dev/fd/62 2018-02-27 16:32:54.861266246 +0100
+@@ -1 +1 @@
+-abc
++def
+
+EOF
+
+check 'patch .nonexistent < f.diff || echo "Status: $?"' <<EOF
+patching file .nonexistent
+Hunk #1 FAILED at 1.
+1 out of 1 hunk FAILED -- saving rejects to file .nonexistent.rej
+$PATCH: **** Can't reopen file .nonexistent : No such file or directory
+Status: 2
+EOF