fix(server): failed provider updates say why

apps/server/src/provider/providerMaintenanceRunner.test.ts

@@ -665,14 +665,43 @@ describe("providerMaintenanceRunner", () => {
       const updateState = result.providers[0]?.updateState;
 
       assert.strictEqual(updateState?.status, "failed");
-      assert.strictEqual(updateState?.message, "Update command exited with code 1.");
-      assert.include(updateState?.output ?? "", "permission denied");
+      assert.strictEqual(
+        updateState?.message,
+        "Update command exited with code 1: Error: Could not detect the Codex installation method.",
+      );
+      assert.include(updateState?.output ?? "", "checking install");
+    }).pipe(
+      Effect.provide(
+        Layer.mergeAll(
+          layerNonWindowsPlatform,
+          layerLatestVersionHttpClient("0.0.0"),
+          layerMockSpawner(() => ({
+            stdout: "checking install\n",
+            stderr: "Error: Could not detect the Codex installation method.\n\n",
+            code: 1,
+          })),
+        ),
+      ),
+    ),
+  );
+
+  it.effect("keeps the exit code message when a failed command prints nothing", () =>
+    Effect.gen(function* () {
+      const { registry } = yield* makeRegistry();
+      const updater = yield* makeTestRunner(registry);
+
+      const result = yield* updater.updateProvider(CODEX_DRIVER);
+
+      assert.strictEqual(
+        result.providers[0]?.updateState?.message,
+        "Update command exited with code 1.",
+      );
     }).pipe(
       Effect.provide(
         Layer.mergeAll(
           layerNonWindowsPlatform,
           layerLatestVersionHttpClient("0.0.0"),
-          layerMockSpawner(() => ({ stderr: "permission denied", code: 1 })),
+          layerMockSpawner(() => ({ code: 1 })),
         ),
       ),
     ),

apps/server/src/provider/providerMaintenanceRunner.ts

@@ -242,14 +242,30 @@ function commandOutput(result: ProviderMaintenanceCommandResult): string | null
   return truncateText(output, UPDATE_OUTPUT_MAX_BYTES);
 }
 
+// Updaters print their reason last, usually on stderr.
+function lastOutputLine(result: ProviderMaintenanceCommandResult): string | null {
+  for (const output of [result.stderr, result.stdout]) {
+    const line = output
+      .split(/\r\n|\r|\n/)
+      .map(toProgressLine)
+      .findLast(Boolean);
+    if (line) {
+      return line;
+    }
+  }
+  return null;
+}
+
 function failureMessage(result: ProviderMaintenanceCommandResult): string {
   if (result.timedOut) {
     return "Update timed out.";
   }
-  if (result.exitCode !== null && result.exitCode !== 0) {
-    return `Update command exited with code ${result.exitCode}.`;
-  }
-  return "Update command failed.";
+  const summary =
+    result.exitCode !== null && result.exitCode !== 0
+      ? `Update command exited with code ${result.exitCode}`
+      : "Update command failed";
+  const reason = lastOutputLine(result);
+  return reason ? `${summary}: ${reason}` : `${summary}.`;
 }
 
 function isOutdatedProvider(provider: ServerProvider | undefined): boolean {
@@ -474,6 +490,13 @@ export const make = Effect.fn("ProviderMaintenanceRunner.make")(function* () {
             const result = yield* runMaintenanceCommand(command, setRunningMessage);
             const finishedAt = yield* nowIso;
             if (result.timedOut || result.exitCode !== 0) {
+              yield* Effect.logWarning("Provider update command failed", {
+                provider,
+                command: describeCommand(command),
+                exitCode: result.exitCode,
+                timedOut: result.timedOut,
+                output: commandOutput(result),
+              });
               return yield* finish(
                 makeUpdateState({
                   status: "failed",