ci(triage): match test as a name segment, not just a whole component

.github/workflows/pr-checks.yml

@@ -68,6 +68,22 @@ jobs:
       - name: Test release tag resolver
         run: scripts/test-resolve-release-tag.sh
 
+  triage-detector:
+    name: triage detector matrix
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          persist-credentials: false
+
+      # pr-triage.yml runs on pull_request_target and never checks out PR
+      # code, so its inline detector can only be exercised here, where the
+      # proposed workflow body IS the checked-out one.
+      - name: Test inline-test detector
+        run: node scripts/test-pr-triage-detect.mjs
+
   test:
     name: test (${{ matrix.toolchain }})
     runs-on: ubuntu-latest

.github/workflows/pr-triage.yml

@@ -76,9 +76,106 @@ jobs:
             // line after horizontal whitespace, covering bare, cfg(test), namespaced,
             // optional leading ::, and raw-identifier (r#test) forms. No head-file fetch
             // or lexer: needs-tests is advisory, not a merge gate.
-            const addsInlineTest = files.some(f =>
-              f.filename.endsWith(".rs") && f.patch &&
-              /^\+[ \t]*#\[[ \t]*(?:cfg[ \t]*\([ \t]*test[ \t]*\)|(?:::[ \t]*)?(?:[\w-]+[ \t]*::[ \t]*)*(?:r#)?test\b)/m.test(f.patch));
+            //
+            // The final path component may also carry `test` as an underscore-delimited
+            // segment, so third-party harnesses land without enumerating them one by one
+            // (#[test_case(1)], #[wasm_bindgen_test]). It is deliberately a segment and
+            // not a substring: a substring would also match #[contest] / #[latest], and a
+            // false positive here SUPPRESSES needs-tests rather than adding it. This
+            // heuristic has to fail loud, because a wrongly labeled PR gets corrected by
+            // the author while a wrongly cleared one is invisible. That trade costs the
+            // no-underscore harness names (#[rstest]), which stay unmatched on purpose.
+            //
+            // The segment classes are [A-Za-z0-9]+ rather than \w+ on purpose, so that `_`
+            // is only ever the literal delimiter. \w+ contains `_`, which makes the repeat
+            // ambiguous and backtracks exponentially: on this workflow's pull_request_target
+            // trigger f.patch is fork-controlled, so `#[test` followed by a long `_a` run is
+            // a permissionless stall of the triage job.
+            // Rust allows whitespace, line breaks, and comments between the
+            // attribute path and ] or (. A flat regex cannot decide that
+            // boundary: `//` runs to end of line, and block comments NEST, which
+            // is beyond regular languages — every enumeration of comment
+            // spellings so far has either dropped a legal separator (regressing
+            // real tests into needs-tests) or let unrelated patch records
+            // complete each other (clearing needs-tests from a testless PR, the
+            // invisible direction). So the closer is found by a token-aware
+            // scan instead: it consumes horizontal whitespace, `//`-to-newline,
+            // and depth-counted `/* */` runs, and accepts only when the first
+            // real token after the attribute path is `]` or `(`.
+            //
+            // Association is positional: the scan starts on the attribute's own
+            // added line and may continue ONLY through the immediately following
+            // added lines (a context line, hunk header, or removal breaks the
+            // chain). Unrelated `]`/`(` lines elsewhere in the patch can never
+            // complete a path they do not adjoin. The continuation is bounded;
+            // past the bound the scan gives up and reports NO inline test, which
+            // fails toward the loud label rather than the silent clearance.
+            //
+            // The detector body is fenced by the TRIAGE_DETECTOR markers so
+            // scripts/test-pr-triage-detect.mjs can extract and run it against
+            // the committed case matrix. Keep the fenced block self-contained.
+            // TRIAGE_DETECTOR_BEGIN
+            const TEST_ATTR_PATH =
+              "(?:cfg[ \\t]*\\([ \\t]*test[ \\t]*\\)|(?:::[ \\t]*)?(?:[\\w-]+[ \\t]*::[ \\t]*)*(?:r#)?(?:[A-Za-z0-9]+_)*test(?:_[A-Za-z0-9]+)*)";
+            // Anchored to the start of one added line; group 1 is whatever
+            // follows the path on that line, handed to the separator scan.
+            const TEST_ATTR_LINE = new RegExp(
+              "^[ \\t]*#\\[[ \\t]*" + TEST_ATTR_PATH + "([\\s\\S]*)$"
+            );
+            // An attribute split across more added lines than this is not a
+            // spelling anyone writes; refusing to scan further keeps the walk
+            // linear in the patch and fails toward the loud label.
+            const MAX_ATTR_CONTINUATION_LINES = 16;
+            // segs[0] is the remainder of the attribute's own line; each later
+            // entry is the text of one immediately following added line. True
+            // only when the first non-separator token across them is ] or (.
+            // Single forward pass, no backtracking: fork-controlled input.
+            function attrCloserFollows(segs) {
+              let depth = 0; // open block-comment nesting carried across lines
+              for (const seg of segs) {
+                let i = 0;
+                while (i < seg.length) {
+                  if (depth > 0) {
+                    if (seg.startsWith("/*", i)) { depth += 1; i += 2; }
+                    else if (seg.startsWith("*/", i)) { depth -= 1; i += 2; }
+                    else { i += 1; }
+                    continue;
+                  }
+                  const c = seg[i];
+                  if (c === " " || c === "\t") { i += 1; continue; }
+                  if (seg.startsWith("//", i)) break; // comment to end of line
+                  if (seg.startsWith("/*", i)) { depth = 1; i += 2; continue; }
+                  return c === "]" || c === "(";
+                }
+                // Line exhausted inside separators; the newline is itself a
+                // separator, so continue on the next added line.
+              }
+              return false; // out of adjoined lines (or bound hit): stay loud
+            }
+            function patchAddsInlineTest(patch) {
+              const lines = patch.split("\n");
+              for (let i = 0; i < lines.length; i++) {
+                if (lines[i][0] !== "+") continue;
+                const m = TEST_ATTR_LINE.exec(lines[i].slice(1));
+                if (m === null) continue;
+                const segs = [m[1]];
+                for (
+                  let j = i + 1;
+                  j < lines.length &&
+                  lines[j][0] === "+" &&
+                  segs.length <= MAX_ATTR_CONTINUATION_LINES;
+                  j++
+                ) {
+                  segs.push(lines[j].slice(1));
+                }
+                if (attrCloserFollows(segs)) return true;
+              }
+              return false;
+            }
+            // TRIAGE_DETECTOR_END
+            const addsInlineTest = files.some(
+              f => f.filename.endsWith(".rs") && !!f.patch && patchAddsInlineTest(f.patch)
+            );
             const touchedTests =
               names.some(n => n.includes("/tests/") || n.endsWith("_test.rs")) || addsInlineTest;
             if (changedRust && !touchedTests) want.add("needs-tests");

scripts/test-pr-triage-detect.mjs

@@ -0,0 +1,172 @@
+#!/usr/bin/env node
+// Case matrix for the inline-test detector embedded in
+// .github/workflows/pr-triage.yml. The workflow runs on pull_request_target
+// and deliberately never checks out PR code, so the detector cannot be tested
+// where it runs; this script extracts the fenced TRIAGE_DETECTOR block from
+// the committed workflow body and exercises it here, where pr-checks.yml DOES
+// check out the proposed workflow. If the fence markers move or the block
+// stops being self-contained, this script fails loudly rather than testing a
+// stale copy.
+//
+// The matrix encodes the review contract for the detector
+// (Gitlawb/node#277): legal Rust separators between the attribute path and
+// its ]/( delimiter must be accepted (line comments, nested block comments,
+// splits onto immediately following added lines), while unrelated patch
+// records — delimiter-looking lines before the path, later in the hunk, or in
+// another hunk — must never complete a path they do not adjoin. False
+// negatives here SUPPRESS the needs-tests label silently, so every uncertain
+// path in the detector is required to answer "no inline test".
+
+import { readFileSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const repoRoot = join(dirname(fileURLToPath(import.meta.url)), "..");
+const workflow = readFileSync(
+  join(repoRoot, ".github/workflows/pr-triage.yml"),
+  "utf8"
+);
+
+const BEGIN = "// TRIAGE_DETECTOR_BEGIN";
+const END = "// TRIAGE_DETECTOR_END";
+const begin = workflow.indexOf(BEGIN);
+const end = workflow.indexOf(END);
+if (begin === -1 || end === -1 || end <= begin) {
+  console.error("FAIL: TRIAGE_DETECTOR fence not found in pr-triage.yml");
+  process.exit(1);
+}
+const block = workflow.slice(begin + BEGIN.length, end);
+
+let patchAddsInlineTest;
+try {
+  const factory = new Function(`${block}\nreturn patchAddsInlineTest;`);
+  patchAddsInlineTest = factory();
+} catch (err) {
+  console.error(
+    "FAIL: fenced detector block is not self-contained JavaScript:",
+    err.message
+  );
+  process.exit(1);
+}
+
+// Each patch is the `patch` field GitHub's listFiles API returns: hunk
+// headers plus +/-/space-prefixed lines, no ---/+++ file headers.
+const cases = [
+  // ── Accepted spellings ────────────────────────────────────────────────
+  ["bare same-line", "@@ -1,0 +1,2 @@\n+#[test]\n+fn a() {}", true],
+  ["cfg(test)", "@@ -1,0 +1,1 @@\n+#[cfg(test)]", true],
+  ["indented with inner space", "@@ -1,0 +1,1 @@\n+    #[ test ]", true],
+  [
+    "namespaced with args",
+    '@@ -1,0 +1,1 @@\n+#[tokio::test(flavor = "multi_thread")]',
+    true,
+  ],
+  ["test_case harness", "@@ -1,0 +1,1 @@\n+#[test_case(1)]", true],
+  ["wasm_bindgen_test harness", "@@ -1,0 +1,1 @@\n+#[wasm_bindgen_test]", true],
+  ["raw identifier", "@@ -1,0 +1,1 @@\n+#[r#test]", true],
+  [
+    "line comment then closer on next added line",
+    "@@ -1,0 +1,2 @@\n+#[test // rationale\n+]",
+    true,
+  ],
+  [
+    "nested block comment, same line",
+    "@@ -1,0 +1,1 @@\n+#[test /* outer /* inner */ outer */]",
+    true,
+  ],
+  [
+    "block comment spanning added lines",
+    "@@ -1,0 +1,3 @@\n+#[test /* why\n+   still why */ ]\n+fn a() {}",
+    true,
+  ],
+  [
+    "path-only line, ( on the immediately following added line",
+    "@@ -1,0 +1,2 @@\n+#[test_case\n+(1)]",
+    true,
+  ],
+  [
+    "whitespace-only continuation before closer",
+    "@@ -1,0 +1,3 @@\n+#[test\n+\t\n+]",
+    true,
+  ],
+  // ── Rejected spellings and adversarial shapes ─────────────────────────
+  ["rstest stays excluded", "@@ -1,0 +1,1 @@\n+#[rstest]", false],
+  ["substring #[testable]", "@@ -1,0 +1,1 @@\n+#[testable]", false],
+  ["substring #[contest]", "@@ -1,0 +1,1 @@\n+#[contest]", false],
+  [
+    "delimiter-looking line BEFORE the path",
+    "@@ -1,0 +1,2 @@\n+(\n+#[test_case",
+    false,
+  ],
+  [
+    "raw-string fixture path + unrelated ( later in the same hunk",
+    '@@ -1,0 +1,5 @@\n+let s = r#"\n+#[test_case\n+not a separator token\n+"#;\n+let t = (1);',
+    false,
+  ],
+  [
+    "path at end of one hunk, closer in another hunk",
+    "@@ -1,0 +1,1 @@\n+#[test_case\n@@ -10,0 +11,1 @@\n+(1)]",
+    false,
+  ],
+  [
+    "closer only on a context line",
+    "@@ -1,1 +1,1 @@\n+#[test_case\n (1)]",
+    false,
+  ],
+  [
+    "closer only on a removed line",
+    "@@ -1,1 +1,1 @@\n+#[test_case\n-(1)]",
+    false,
+  ],
+  [
+    "unfinished block comment never closes",
+    "@@ -1,0 +1,2 @@\n+#[test /*\n+ still open",
+    false,
+  ],
+  [
+    "continuation bound exceeded stays loud",
+    "@@ -1,0 +1,40 @@\n+#[test /*\n" + "+ filler\n".repeat(30) + "+ */ ]",
+    false,
+  ],
+];
+
+let failures = 0;
+for (const [name, patch, expected] of cases) {
+  const got = patchAddsInlineTest(patch);
+  if (got !== expected) {
+    failures += 1;
+    console.error(`FAIL: ${name}: expected ${expected}, got ${got}`);
+  }
+}
+
+// Runtime probe: the detector walks fork-controlled input on
+// pull_request_target, so a pathological head must not stall the job. The
+// long `_a` run is the historical exponential-backtracking shape for the
+// attribute-path regex; the comment run exercises the scanner loop.
+const probes = [
+  ["long _a run", "@@ -1,0 +1,1 @@\n+#[test" + "_a".repeat(30000), false],
+  [
+    "long unclosed comment line",
+    "@@ -1,0 +1,1 @@\n+#[test /*" + " *".repeat(30000),
+    false,
+  ],
+];
+for (const [name, patch, expected] of probes) {
+  const t0 = process.hrtime.bigint();
+  const got = patchAddsInlineTest(patch);
+  const ms = Number(process.hrtime.bigint() - t0) / 1e6;
+  if (got !== expected) {
+    failures += 1;
+    console.error(`FAIL: probe ${name}: expected ${expected}, got ${got}`);
+  }
+  if (ms > 1000) {
+    failures += 1;
+    console.error(`FAIL: probe ${name}: took ${ms.toFixed(0)}ms (>1000ms)`);
+  }
+}
+
+if (failures) {
+  console.error(`${failures} failure(s) across ${cases.length + probes.length} cases`);
+  process.exit(1);
+}
+console.log(`ok: ${cases.length + probes.length} detector cases passed`);