do not compute diffs if either side fatal errors

Author: meorphis

dist/build.js

@@ -8,6 +8,7 @@ import { tmpdir } from "os";
 import { join } from "path";
 import {
   type Outcomes,
+  conclusions,
   FailRunOn,
   getDiffLanguages,
   shouldFailRun,
@@ -297,6 +298,16 @@ async function main() {
         for (const [lang, head] of Object.entries(state.outcomes)) {
           const base = state.baseOutcomes[lang];
 
+          if (
+            (head.commit?.conclusion &&
+              conclusions.fatal.includes(head.commit?.conclusion)) ||
+            (base.commit?.conclusion &&
+              conclusions.fatal.includes(base.commit?.conclusion))
+          ) {
+            // diff is indeterminate if either build failed fatally
+            continue;
+          }
+
           if (head.commit?.conclusion === "merge_conflict") {
             // Don't determine diff until base has also concluded so its
             // codegen branch is in its final state before we compare.

dist/internalPreview.js

@@ -91,6 +91,19 @@ export function shouldFailRun({
   return true;
 }
 
+export const conclusions = {
+  fatal: [
+    "fatal",
+    "payment_required",
+    "timed_out",
+    "upstream_merge_conflict",
+    "version_bump",
+  ],
+  conflict: ["merge_conflict"],
+  diagnostic: ["error", "warning", "note"],
+  success: ["success", "noop", "cancelled"],
+};
+
 export function categorizeOutcome({
   outcome,
   baseOutcome,
@@ -141,19 +154,6 @@ export function categorizeOutcome({
       : outcome.diagnostics,
   );
 
-  const conclusions = {
-    fatal: [
-      "fatal",
-      "payment_required",
-      "timed_out",
-      "upstream_merge_conflict",
-      "version_bump",
-    ],
-    conflict: ["merge_conflict"],
-    diagnostic: ["error", "warning", "note"],
-    success: ["success", "noop", "cancelled"],
-  };
-
   const checks = getNewChecks(headChecks, baseChecks);
   const checkFailures = CheckType.filter(
     (checkType) =>