[PATCH 1/2] patch-id: fix stable patch id for binary / header-only

["Jerry Zhang via GitGitGadget" <gitgitgadget@gmail.com>]

From: Jerry Zhang <jerry@skydio.com>

Previous logic here skipped flushing the hunks for binary
and header-only patch ids, which would always result in a
patch-id of 0000.

Reorder the logic to branch into 3 cases for populating the
patch body: header-only which populates nothing, binary which
populates the object ids, and normal which populates the text
diff. All branches will end up flushing the hunk.

Update the test to run on both binary and normal files.

Signed-off-by: Jerry Zhang <jerry@skydio.com>
---
 diff.c                     | 32 ++++++++++++++------------------
 t/t3419-rebase-patch-id.sh | 19 +++++++++++++------
 2 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/diff.c b/diff.c
index dd68281ba44..2f8f0c2e4f4 100644
--- a/diff.c
+++ b/diff.c
@@ -6248,30 +6248,26 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
 			the_hash_algo->update_fn(&ctx, p->two->path, len2);
 		}
 
-		if (diff_header_only)
-			continue;
-
-		if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
-		    fill_mmfile(options->repo, &mf2, p->two) < 0)
-			return error("unable to read files to diff");
-
-		if (diff_filespec_is_binary(options->repo, p->one) ||
+		if (diff_header_only) {
+			// Don't do anything since we're only populating header info
+		} else if (diff_filespec_is_binary(options->repo, p->one) ||
 		    diff_filespec_is_binary(options->repo, p->two)) {
 			the_hash_algo->update_fn(&ctx, oid_to_hex(&p->one->oid),
 					the_hash_algo->hexsz);
 			the_hash_algo->update_fn(&ctx, oid_to_hex(&p->two->oid),
 					the_hash_algo->hexsz);
-			continue;
+		} else {
+			if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
+			    fill_mmfile(options->repo, &mf2, p->two) < 0)
+				return error("unable to read files to diff");
+			xpp.flags = 0;
+			xecfg.ctxlen = 3;
+			xecfg.flags = XDL_EMIT_NO_HUNK_HDR;
+			if (xdi_diff_outf(&mf1, &mf2, NULL,
+					  patch_id_consume, &data, &xpp, &xecfg))
+				return error("unable to generate patch-id diff for %s",
+					     p->one->path);
 		}
-
-		xpp.flags = 0;
-		xecfg.ctxlen = 3;
-		xecfg.flags = XDL_EMIT_NO_HUNK_HDR;
-		if (xdi_diff_outf(&mf1, &mf2, NULL,
-				  patch_id_consume, &data, &xpp, &xecfg))
-			return error("unable to generate patch-id diff for %s",
-				     p->one->path);
-
 		if (stable)
 			flush_one_hunk(oid, &ctx);
 	}
diff --git a/t/t3419-rebase-patch-id.sh b/t/t3419-rebase-patch-id.sh
index 295040f2fe3..f7b7e9e5b7c 100755
--- a/t/t3419-rebase-patch-id.sh
+++ b/t/t3419-rebase-patch-id.sh
@@ -46,10 +46,6 @@ test_expect_success 'setup: 500 lines' '
 	git cherry-pick main >/dev/null 2>&1
 '
 
-test_expect_success 'setup attributes' '
-	echo "file binary" >.gitattributes
-'
-
 test_expect_success 'detect upstream patch' '
 	git checkout -q main &&
 	scramble file &&
@@ -58,7 +54,13 @@ test_expect_success 'detect upstream patch' '
 	git checkout -q other^{} &&
 	git rebase main &&
 	git rev-list main...HEAD~ >revs &&
-	test_must_be_empty revs
+	test_must_be_empty revs &&
+	echo "file binary" >.gitattributes &&
+	git checkout -q other^{} &&
+	git rebase main &&
+	git rev-list main...HEAD~ >revs &&
+	test_must_be_empty revs &&
+	rm .gitattributes
 '
 
 test_expect_success 'do not drop patch' '
@@ -68,7 +70,12 @@ test_expect_success 'do not drop patch' '
 	git commit -q -m squashed &&
 	git checkout -q other^{} &&
 	test_must_fail git rebase squashed &&
-	git rebase --quit
+	git rebase --abort &&
+	echo "file binary" >.gitattributes &&
+	git checkout -q other^{} &&
+	test_must_fail git rebase squashed &&
+	git rebase --abort &&
+	rm .gitattributes
 '
 
 test_done
-- 
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