merge-ort: fix bug with renormalization and rename/delete conflicts

newren · gitster · commit d30126c20d58 · 2021-12-30T10:40:26.000-08:00
Ever since commit a492d53 ("merge-ort: ensure we consult df_conflict and path_conflicts", 2021-06-30), when renormalization is active AND a file is involved in a rename/delete conflict BUT the file is unmodified (either before or after renormalization), merge-ort was running into an assertion failure. Prior to that commit (or if assertions were compiled out), merge-ort would mis-merge instead, ignoring the rename/delete conflict and just deleting the file. Remove the assertions, fix the code appropriately, leave some good comments in the code, and add a testcase for this situation. Reported-by: Ralf Thielow <ralf.thielow@gmail.com> Signed-off-by: Elijah Newren <newren@gmail.com> Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/merge-ort.c b/merge-ort.c
@@ -3841,9 +3841,22 @@ static void process_entry(struct merge_options *opt,
 		if (opt->renormalize &&
 		    blob_unchanged(opt, &ci->stages[0], &ci->stages[side],
 				   path)) {
-			ci->merged.is_null = 1;
-			ci->merged.clean = 1;
-			assert(!ci->df_conflict && !ci->path_conflict);
+			if (!ci->path_conflict) {
+				/*
+				 * Blob unchanged after renormalization, so
+				 * there's no modify/delete conflict after all;
+				 * we can just remove the file.
+				 */
+				ci->merged.is_null = 1;
+				ci->merged.clean = 1;
+				 /*
+				  * file goes away => even if there was a
+				  * directory/file conflict there isn't one now.
+				  */
+				ci->df_conflict = 0;
+			} else {
+				/* rename/delete, so conflict remains */
+			}
 		} else if (ci->path_conflict &&
 			   oideq(&ci->stages[0].oid, &ci->stages[side].oid)) {
 			/*
diff --git a/t/t6418-merge-text-auto.sh b/t/t6418-merge-text-auto.sh
@@ -204,4 +204,30 @@ test_expect_success 'Test delete/normalize conflict' '
 	test_path_is_missing file
 '
 
+test_expect_success 'rename/delete vs. renormalization' '
+	git init subrepo &&
+	(
+		cd subrepo &&
+		echo foo >oldfile &&
+		git add oldfile &&
+		git commit -m original &&
+
+		git branch rename &&
+		git branch nuke &&
+
+		git checkout rename &&
+		git mv oldfile newfile &&
+		git commit -m renamed &&
+
+		git checkout nuke &&
+		git rm oldfile &&
+		git commit -m deleted &&
+
+		git checkout rename^0 &&
+		test_must_fail git -c merge.renormalize=true merge nuke >out &&
+
+		grep "rename/delete" out
+	)
+'
+
 test_done
