Re: [PATCH] mergetool: respect autocrlf by using checkout-index

Junio C Hamano [off-list ref] writes:

Charles Bailey [off-list ref] writes:

quoted

I suspect that the LF endings in the file is due to the fact that in
builtin-merge-file.c, the file is opened (fopen) in binary mode
("wb"), but xdl_merge terminates all lines with a raw '\n'.

The obvious fix would be to change fopen in builtin-file-merge.c to
use "w" instead, but this doesn't work in a number of scenarios. In
particular, it is wrong for repositories on windows with core.autocrlf
set to false, and would not fix non-windows repositories with
core.autocrlf set to true.

Currently, I've no idea as to what the solution should be.

"git file-merge" is designed to be a replacement for stock RCS merge, and
unfortunately it does not call convert_to_working_tree(), nor has any way
to know for which path it should take the attributes to apply to affect
what convert_to_working_tree() should do even if it were to call it.

I think we would need a new option to the command that says "pretend this
is about merging this path, and use the gitattributes specified for it
when writing out the result."

Perhaps something along this line to teach

    $ git merge-file --attribute-path=frotz.c file1 orig_file file2

to merge what happened since orig_file to file2 into file1, and deposit
the result after converting it appropriately for path "frotz.c" obeying
core.autocrlf and gitattribute rules.

I see rerere.c::merge() has the exact same issue, but its breakage is half
hidden by its use of fopen(path, "w").  It should explicitly use
convert_to_working_tree() like this patch does, and write the results out
in binary mode.

 builtin-merge-file.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git i/builtin-merge-file.c w/builtin-merge-file.c
index 96edb97..61d1092 100644
--- i/builtin-merge-file.c
+++ w/builtin-merge-file.c

@@ -5,7 +5,7 @@
 #include "parse-options.h"
 
 static const char *const merge_file_usage[] = {
-	"git merge-file [options] [-L name1 [-L orig [-L name2]]] file1 orig_file file2",
+	"git merge-file [options] [-L name1 [-L orig [-L name2]]] [--attribute-path path] file1 orig_file file2",
 	NULL
 };
 

@@ -30,10 +30,13 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 	int merge_level = XDL_MERGE_ZEALOUS_ALNUM;
 	int merge_style = 0, quiet = 0;
 	int nongit;
+	char *attribute_path = NULL;
 
 	struct option options[] = {
 		OPT_BOOLEAN('p', "stdout", &to_stdout, "send results to standard output"),
 		OPT_SET_INT(0, "diff3", &merge_style, "use a diff3 based merge", XDL_MERGE_DIFF3),
+		OPT_STRING('a', "attribute-path", &attribute_path, "path",
+			   "apply work-tree conversion for the path"),
 		OPT__QUIET(&quiet),
 		OPT_CALLBACK('L', NULL, names, "name",
 			     "set labels for file1/orig_file/file2", &label_cb),

@@ -73,6 +76,19 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 	for (i = 0; i < 3; i++)
 		free(mmfs[i].ptr);
 
+	if (ret >= 0 && attribute_path) {
+		struct strbuf buf = STRBUF_INIT;
+		ret = convert_to_working_tree(attribute_path,
+					      result.ptr, result.size,
+					      &buf);
+		free(result.ptr);
+		if (!ret) {
+			size_t len;
+			result.ptr = strbuf_detach(&buf, &len);
+			result.size = len;
+		}
+	}
+
 	if (ret >= 0) {
 		const char *filename = argv[0];
 		FILE *f = to_stdout ? stdout : fopen(filename, "wb");