Merge pull request #14197 from NixOS/backport-14191-to-2.32-maintenance

[Backport 2.32-maintenance] libutil: Fix renderAuthorityAndPath unreachable for path:/ URLs

src/libutil-tests/url.cc

@@ -868,6 +868,12 @@ TEST_P(ParsedURLPathSegmentsTest, segmentsAreCorrect)
     EXPECT_EQ(encodeUrlPath(segments), testCase.path);
 }
 
+TEST_P(ParsedURLPathSegmentsTest, to_string)
+{
+    const auto & testCase = GetParam();
+    EXPECT_EQ(testCase.url, parseURL(testCase.url).to_string());
+}
+
 INSTANTIATE_TEST_SUITE_P(
     ParsedURL,
     ParsedURLPathSegmentsTest,
@@ -886,6 +892,13 @@ INSTANTIATE_TEST_SUITE_P(
             .skipEmpty = false,
             .description = "empty_authority_empty_path",
         },
+        ParsedURLPathSegmentsTestCase{
+            .url = "path:/",
+            .segments = {"", ""},
+            .path = "/",
+            .skipEmpty = false,
+            .description = "empty_authority_root_path",
+        },
         ParsedURLPathSegmentsTestCase{
             .url = "scheme:///",
             .segments = {"", ""},

src/libutil/url.cc

@@ -350,7 +350,7 @@ std::string ParsedURL::renderAuthorityAndPath() const
            must either be empty or begin with a slash ("/") character. */
         assert(path.empty() || path.front().empty());
         res += authority->to_string();
-    } else if (std::ranges::equal(std::views::take(path, 2), std::views::repeat("", 2))) {
+    } else if (std::ranges::equal(std::views::take(path, 3), std::views::repeat("", 3))) {
         /* If a URI does not contain an authority component, then the path cannot begin
            with two slash characters ("//") */
         unreachable();