ll-merge: make callers responsible for showing warnings

Since some callers may want to send warning messages to somewhere other
than stdout/stderr, stop printing "warning: Cannot merge binary files"
from ll-merge and instead modify the return status of ll_merge() to
indicate when a merge of binary files has occurred.  Message printing
probably does not belong in a "low-level merge" anyway.

This commit continues printing the message as-is, just from the callers
instead of within ll_merge().  Future changes will start handling the
message differently in the merge-ort codepath.

There was one special case here: the callers in rerere.c do NOT check
for and print such a message; since those code paths explicitly skip
over binary files, there is no reason to check for a return status of
LL_MERGE_BINARY_CONFLICT or print the related message.

Note that my methodology included first modifying ll_merge() to return
a struct, so that the compiler would catch all the callers for me and
ensure I had modified all of them.  After modifying all of them, I then
changed the struct to an enum.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/rerere.c b/rerere.c
index d83d58df4f..d26627c593 100644
--- a/rerere.c
+++ b/rerere.c
@@ -609,19 +609,20 @@ static int try_merge(struct index_state *istate,
 		     const struct rerere_id *id, const char *path,
 		     mmfile_t *cur, mmbuffer_t *result)
 {
-	int ret;
+	enum ll_merge_result ret;
 	mmfile_t base = {NULL, 0}, other = {NULL, 0};
 
 	if (read_mmfile(&base, rerere_path(id, "preimage")) ||
-	    read_mmfile(&other, rerere_path(id, "postimage")))
-		ret = 1;
-	else
+	    read_mmfile(&other, rerere_path(id, "postimage"))) {
+		ret = LL_MERGE_CONFLICT;
+	} else {
 		/*
 		 * A three-way merge. Note that this honors user-customizable
 		 * low-level merge driver settings.
 		 */
 		ret = ll_merge(result, path, &base, NULL, cur, "", &other, "",
 			       istate, NULL);
+	}
 
 	free(base.ptr);
 	free(other.ptr);