[PATCH v2 6/7] merge-ll: handle external driver status before reading result

[Jeff King <peff@peff.net>]

After running an external merge driver, ll_ext_merge() reads its output
and cleans up the temporary files before converting the exit status to
an ll_merge_result.

Move that conversion immediately after run_command(). This will let us
override the result if reading the output fails, without having to fake
an exit status. No behavior change yet.

It is tempting to only call read_mmfile() when we have LL_MERGE_OK, but
callers do care about the result even with LL_MERGE_CONFLICT (e.g., the
output may contain a partial). I think we could safely skip it for
LL_MERGE_ERROR, but that's a rare case and not worth complicating the
code for.

Signed-off-by: Jeff King <peff@peff.net>
---
 merge-ll.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/merge-ll.c b/merge-ll.c
index 7fab7c5438..4d82836bc5 100644
--- a/merge-ll.c
+++ b/merge-ll.c
@@ -240,20 +240,20 @@ static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
 	child.use_shell = 1;
 	strvec_push(&child.args, cmd.buf);
 	status = run_command(&child);
-
-	/* We can ignore errors; result is left NULL/0 in that case. */
-	read_mmfile(result, temp[1]);
-
-	for (i = 0; i < 3; i++)
-		unlink_or_warn(temp[i]);
-	strbuf_release(&cmd);
 	if (!status)
 		ret = LL_MERGE_OK;
 	else if (status <= 128)
 		ret = LL_MERGE_CONFLICT;
 	else
 		/* died due to a signal: WTERMSIG(status) + 128 */
 		ret = LL_MERGE_ERROR;
+
+	/* We can ignore errors; result is left NULL/0 in that case. */
+	read_mmfile(result, temp[1]);
+
+	for (i = 0; i < 3; i++)
+		unlink_or_warn(temp[i]);
+	strbuf_release(&cmd);
 	return ret;
 }
 
-- 
2.56.0.354.gb6b32d5be5