[bug-patch] [RESEND4 PATCH] Fix error handling with git-style patches

[Lubomir Rintel]

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.
---
 src/patch.c       | 12 ++++++++----
 tests/Makefile.am |  1 +
 tests/git-error   | 29 +++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 tests/git-error

diff --git a/src/patch.c b/src/patch.c
index 81c7a02..e6fdd77 100644
--- a/src/patch.c
+++ b/src/patch.c
@@ -1939,8 +1939,12 @@ 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;
@@ -1958,8 +1962,8 @@ 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;
            }
@@ -1968,7 +1972,7 @@ 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. */
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 16f8693..5ce000a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -41,6 +41,7 @@ TESTS = \
        filename-choice \
        git-binary-diff \
        git-cleanup \
+       git-error \
        garbage \
        global-reject-files \
        inname \
diff --git a/tests/git-error b/tests/git-error
new file mode 100644
index 0000000..0071957
--- /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
-- 
2.19.2