compute: a failure implicates only toolchains no successful build of the release used

Author: rigor789

shared/compute.ts

@@ -199,15 +199,26 @@ export function verifiedPairs(
 		]);
 }
 
+/**
+ * A failed build pins several toolchains at once and cannot say which one is
+ * to blame, so a failure only implicates a toolchain version that no
+ * successful build of the same release used.
+ */
 function verifiedFor(
 	packageName: string,
 	version: string,
 	verified: VerificationResult[],
 	outcome: ResultClass,
 ): VersionCompatibility["verified"] {
+	const forThisVersion = (pairs: ReturnType<typeof verifiedPairs>) =>
+		pairs.filter((pair) => pair.package === packageName && pair.version === version);
+	const successes = forThisVersion(verifiedPairs(verified, "success"));
+	const provenToWork = (pair: (typeof successes)[number]) =>
+		successes.some((ok) => ok.toolchain === pair.toolchain && sameLine(ok.toolchainVersion, pair.toolchainVersion));
+
 	const result: VersionCompatibility["verified"] = {};
-	for (const pair of verifiedPairs(verified, outcome)) {
-		if (pair.package !== packageName || pair.version !== version) {
+	for (const pair of forThisVersion(verifiedPairs(verified, outcome))) {
+		if (outcome !== "success" && provenToWork(pair)) {
 			continue;
 		}
 		const list = (result[pair.toolchain] ??= []);

test/compute.test.ts

@@ -256,3 +256,29 @@ describe("inferred failures", () => {
 		expect(doc.packages["@nativescript/android"].versions["9.1.1"].inferred).toBeUndefined();
 	});
 });
+
+describe("failure attribution", () => {
+	it("blames only the toolchain no successful build of the release used", () => {
+		const doc = buildDocument({
+			generatedAt: "2026-09-09T00:00:00.000Z",
+			toolchains: { xcode: [], cocoapods: [], compileSdk: [{ version: "37" }], buildTools: [{ version: "37.0.0" }], jdk: [{ version: "25" }, { version: "21" }], node: [] },
+			packages: [
+				{
+					spec: { name: "@nativescript/android", toolchains: ["compileSdk", "buildTools", "jdk"], keep: 5 },
+					document: { distTags: {}, manifests: [{ version: "9.1.1", requirements: { jdk: ">=17" } }, { version: "9.0.5", requirements: { jdk: ">=17" } }] },
+				},
+			],
+			overrides: { requirements: [], advisories: [] },
+			verified: [
+				{ package: "@nativescript/android", version: "9.1.1", toolchains: { compileSdk: "37", buildTools: "37.0.0", jdk: "25" }, with: { nativescript: "9.1.1", node: "24" }, outcome: "failure", attempts: 2, recordedAt: "2026-09-09T00:00:00Z" },
+				{ package: "@nativescript/android", version: "9.1.1", toolchains: { compileSdk: "37", buildTools: "37.0.0", jdk: "21" }, with: { nativescript: "9.1.1", node: "24" }, recordedAt: "2026-09-09T00:00:00Z" },
+			],
+		});
+		const v911 = doc.packages["@nativescript/android"].versions["9.1.1"];
+		expect(v911.failed).toEqual({ jdk: ["25"] });
+		expect(v911.verified).toEqual({ compileSdk: ["37"], buildTools: ["37.0.0"], jdk: ["21"] });
+		expect(cellFor(doc, "@nativescript/android", "9.0.5", "compileSdk", "37").state).toBe("unverified");
+		expect(cellFor(doc, "@nativescript/android", "9.0.5", "buildTools", "37.0.0").state).toBe("unverified");
+		expect(cellFor(doc, "@nativescript/android", "9.0.5", "jdk", "25").state).toBe("unsupported");
+	});
+});