On 12/27/2021 7:20 PM, Elijah Newren via GitGitGadget wrote:

From: Elijah Newren <redacted>

Ever since commit a492d5331c ("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. 

This "the file is unmodified" is critical, as when I looked at the test,
it seemed too simple. I asked myself, "Why does renormalization matter
here?" Turns out it is just an artifact of the carefully organized cases.

 		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 */
+			}

This breakdown of the cases is informative, and I like how self-contained
the change is.

+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

I tested this on the latest 'master' and saw the following:

  git: merge-ort.c:3846: process_entry: Assertion `!ci->df_conflict && !ci->path_conflict' failed

so it indeed hits this case.

This patch looks good to me. Thanks!

Reviewed-by: Derrick Stolee <redacted>