From 74ba1098efd0cd43a5806b4992eec17732330818 Mon Sep 17 00:00:00 2001
From: Bryce Kwon <bryce@brycekwon.com>
Date: Sat, 17 Oct 2026 12:53:18 -1000
Subject: Keep snapshot members from starting at a slash

A name that was all suffix, such as .tar, settled on a ref called v
with an empty prefix, and an empty snapshot-prefix did the same for a
snapshot asked for by id, so every member of the archive started at /.
---
 source/ui-snapshot.c    | 10 +++++++++-
 tests/t0110-snapshot.sh | 21 +++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/source/ui-snapshot.c b/source/ui-snapshot.c
index 8762407..3c00f66 100644
--- a/source/ui-snapshot.c
+++ b/source/ui-snapshot.c
@@ -29,7 +29,9 @@ static int write_archive_format(const char *format_arg, const char *hex, const c
 
 	strvec_push(&argv, "snapshot");
 	strvec_push(&argv, format_arg);
-	if (prefix) {
+	// An empty prefix means none, since the slash added below would root
+	// every member of the archive at /.
+	if (prefix && *prefix) {
 		struct strbuf buf = STRBUF_INIT;
 
 		strbuf_addstr(&buf, prefix);
@@ -370,6 +372,12 @@ void cgit_print_snapshot(const char *head, const char *hex, const char *filename
 		cgit_print_error_page(404, "Not Found", "Not found");
 		return;
 	}
+	// A name that is all suffix names no revision, though the lookup below
+	// would settle on a ref called v.
+	if (!hex && dwim && strlen(filename) == strlen(f->suffix)) {
+		cgit_print_error_page(404, "Not Found", "Not found");
+		return;
+	}
 	if (!hex && dwim) {
 		hex = ref_from_filename(ctx.repo, filename, f);
 		if (!hex) {
diff --git a/tests/t0110-snapshot.sh b/tests/t0110-snapshot.sh
index 4852e7b..ec0a0b8 100755
--- a/tests/t0110-snapshot.sh
+++ b/tests/t0110-snapshot.sh
@@ -146,4 +146,25 @@ test_expect_success 'a real case collision keeps the v on both tags' '
 	! grep "vtags-1.0.tar.gz" tmp
 '
 
+# A name that is all suffix names no revision, and an empty snapshot-prefix
+# gives the members no leading directory rather than a leading slash.
+test_expect_success 'a snapshot name with nothing before its suffix is refused' '
+	git -C repos/vtags branch v HEAD &&
+	sed "s/^snapshots=tar.gz$/snapshots=tar/" vtagsrc >vtagstarrc &&
+	CGIT_CONFIG="$PWD/vtagstarrc" QUERY_STRING="url=vtags/snapshot/.tar" cgit >tmp &&
+	grep "^Status: 404" tmp
+'
+
+test_expect_success 'an empty snapshot-prefix puts no slash ahead of the members' '
+	{
+		cat vtagstarrc &&
+		echo "repo.snapshot-prefix="
+	} >noprefixrc &&
+	CGIT_CONFIG="$PWD/noprefixrc" QUERY_STRING="url=vtags/snapshot/vtags.tar&id=master" cgit >tmp &&
+	strip_headers <tmp >noprefix.tar &&
+	tar -tf noprefix.tar >members &&
+	grep "^file-1$" members &&
+	! grep "^/" members
+'
+
 test_done
-- 
cgit