Re: [PATCH v2] merge-file: correctly open files when in a subdir

Aleksander Boruch-Gruszecki [off-list ref]
writes:

run_setup_gently() is called before merge-file. This may result in changing
current working directory, which wasn't taken into account when opening a file
for writing.

Fix by prepending the passed prefix. Previous var is left so that error
messages keep refering to the file from the user's working directory
perspective.

Signed-off-by: Aleksander Boruch-Gruszecki
    [off-list ref]

Please don't line wrap the footer.

---
 builtin/merge-file.c  | 3 ++-
 t/t6023-merge-file.sh | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

This patch does not apply.

Please do not line-wrap the patch, either.

     if (ret >= 0) {

The original has a single tab at the beginning of this line to
indent, not four spaces.

Interesting.  Makes us wonder why the one before this new one you
added did not catch the issue, doesn't it?

+
 cp new1.txt test.txt
 test_expect_success "merge without conflict (--quiet)" \
     "git merge-file --quiet test.txt orig.txt new2.txt"

quoted

         const char *filename = argv[0];
-        FILE *f = to_stdout ? stdout : fopen(filename, "wb");
+        const char *fpath = prefix_filename(prefix, prefixlen, argv[0]);
+        FILE *f = to_stdout ? stdout : fopen(fpath, "wb");

         if (!f)
             ret = error("Could not open %s for writing", filename);

diff --git a/t/t6023-merge-file.sh b/t/t6023-merge-file.sh
index 3758961..fdd104c 100755
--- a/t/t6023-merge-file.sh
+++ b/t/t6023-merge-file.sh

@@ -72,6 +72,12 @@ test_expect_success 'works in subdirectory' '
     ( cd dir && git merge-file a.txt o.txt b.txt )
 '

+mkdir -p dir/deep
+cp new1.txt orig.txt new2.txt dir/deep
+test_expect_success 'accounts for subdirectory when writing' '
+    (cd dir && git merge-file deep/new1.txt deep/orig.txt deep/new2.txt)
+'

Interesting.  Makes us wonder why the one before this new one you
added did not catch the issue, doesn't it?

The test before the one added by me does work because merge-file
tries to open "a.txt" for writing in repo root directory, which will create
a file if it does not exist. If you add a directory before the file, trying to
open it will fail. I will additionally check of the file's content to make
the test more clear, however it does actually fail with git 2.3.0.

The issue with line-wrapping and tab changing to space is my own
stupidity, I used an older config with my vim and it mangled the file.
It also probably is what caused the patch to not apply properly.