From 7bc161f8692dfb969489f40bf3eb5bd27bc01f10 Mon Sep 17 00:00:00 2001
From: oliver <97427849+flamboh@users.noreply.github.com>
Date: Sat, 3 Oct 2026 18:40:10 -0700
Subject: [PATCH] fix(web): links to issues no longer strand the pull request
 viewer (#14242)

---
 .../AzureDevOpsPullRequestProvider.ts         |  1 +
 .../BitbucketPullRequestProvider.ts           |  6 +++++
 .../pullRequest/ForgejoPullRequestProvider.ts |  4 ++-
 .../pullRequest/GitHubPullRequestProvider.ts  |  1 +
 .../pullRequest/GitLabPullRequestProvider.ts  |  1 +
 .../src/pullRequest/PullRequestProvider.ts    |  8 +++++-
 .../pullRequest/PullRequestService.test.ts    | 27 +++++++++++++++++++
 .../src/pullRequest/PullRequestService.ts     |  7 ++++-
 .../pullRequest/PullRequestDetailPanel.tsx    |  9 ++++++-
 .../pullRequest/pullRequestDetail.logic.ts    |  7 +++++
 apps/web/src/state/query.ts                   |  7 +++--
 packages/contracts/src/pullRequest.ts         |  1 +
 12 files changed, 73 insertions(+), 6 deletions(-)

diff --git a/apps/server/src/pullRequest/AzureDevOpsPullRequestProvider.ts b/apps/server/src/pullRequest/AzureDevOpsPullRequestProvider.ts
index b11ba6e20563813c433eabe027baa19e1b059d0b..2cdf78c56a1456a264fdad465833c3d7384d0c33 100644
--- a/apps/server/src/pullRequest/AzureDevOpsPullRequestProvider.ts
+++ b/apps/server/src/pullRequest/AzureDevOpsPullRequestProvider.ts
@@ -117,6 +117,7 @@ export function azureDevOpsProviderFailure(
   if (error._tag === "AzureDevOpsCliUnavailableError") return { reason: "missing-tool" };
   if (error._tag === "AzureDevOpsCliAuthenticationError") return { reason: "unauthenticated" };
   if (error._tag === "AzureDevOpsCliRateLimitError") return { reason: "rate-limited" };
+  if (error._tag === "AzureDevOpsPullRequestNotFoundError") return { reason: "not-found" };
   return { reason: "failed" };
 }
 
diff --git a/apps/server/src/pullRequest/BitbucketPullRequestProvider.ts b/apps/server/src/pullRequest/BitbucketPullRequestProvider.ts
index e0ee4c0a85b7b5669edeb3e2856be7dd99b716c0..f553dfd13bc1a23a4518181ecb8832d447b2fe80 100644
--- a/apps/server/src/pullRequest/BitbucketPullRequestProvider.ts
+++ b/apps/server/src/pullRequest/BitbucketPullRequestProvider.ts
@@ -82,6 +82,12 @@ export function bitbucketProviderFailure(
       ...(error.retryAt === undefined ? {} : { retryAt: error.retryAt }),
     };
   }
+  if (
+    (error._tag === "BitbucketResponseError" || error._tag === "BitbucketResponseBodyReadError") &&
+    error.status === 404
+  ) {
+    return { reason: "not-found" };
+  }
   return { reason: "failed" };
 }
 
diff --git a/apps/server/src/pullRequest/ForgejoPullRequestProvider.ts b/apps/server/src/pullRequest/ForgejoPullRequestProvider.ts
index 73d582c9042c8f61617e6b713075dc89ce3fb0c2..12d931279a74c4644f31acc3363a4f3a56955857 100644
--- a/apps/server/src/pullRequest/ForgejoPullRequestProvider.ts
+++ b/apps/server/src/pullRequest/ForgejoPullRequestProvider.ts
@@ -89,7 +89,9 @@ export const make = Effect.gen(function* () {
                   ? "unauthenticated"
                   : error.reason === "rate-limit"
                     ? "rate-limited"
-                    : "failed",
+                    : error.reason === "not-found"
+                      ? "not-found"
+                      : "failed",
           }),
       ),
     );
diff --git a/apps/server/src/pullRequest/GitHubPullRequestProvider.ts b/apps/server/src/pullRequest/GitHubPullRequestProvider.ts
index 5e70c2ee1ed4cefe28ac1837dc9539b59607d835..a51825c2e11b528ab87f4b5d9a9ef0730c54d132 100644
--- a/apps/server/src/pullRequest/GitHubPullRequestProvider.ts
+++ b/apps/server/src/pullRequest/GitHubPullRequestProvider.ts
@@ -115,6 +115,7 @@ export function gitHubProviderFailure(
   if (error._tag === "SourceControlRateLimitPausedError") {
     return { reason: "rate-limited", retryAt: error.retryAt };
   }
+  if (error._tag === "GitHubPullRequestNotFoundError") return { reason: "not-found" };
   return { reason: "failed" };
 }
 
diff --git a/apps/server/src/pullRequest/GitLabPullRequestProvider.ts b/apps/server/src/pullRequest/GitLabPullRequestProvider.ts
index ad089382352a15fd0acdc3e581d0f181d49b3bdc..45034b84787c3210c69bb603a7d71800a06e64bb 100644
--- a/apps/server/src/pullRequest/GitLabPullRequestProvider.ts
+++ b/apps/server/src/pullRequest/GitLabPullRequestProvider.ts
@@ -102,6 +102,7 @@ export function gitLabProviderFailure(
   if (error._tag === "GitLabCliUnavailableError") return { reason: "missing-tool" };
   if (error._tag === "GitLabCliAuthenticationError") return { reason: "unauthenticated" };
   if (error._tag === "GitLabCliRateLimitError") return { reason: "rate-limited" };
+  if (error._tag === "GitLabMergeRequestNotFoundError") return { reason: "not-found" };
   return { reason: "failed" };
 }
 
diff --git a/apps/server/src/pullRequest/PullRequestProvider.ts b/apps/server/src/pullRequest/PullRequestProvider.ts
index cc370637c6014647b7d11e74478b24f701c42612..f13af63304d22d8b7254d54654a86e2244a93345 100644
--- a/apps/server/src/pullRequest/PullRequestProvider.ts
+++ b/apps/server/src/pullRequest/PullRequestProvider.ts
@@ -52,7 +52,13 @@ export class PullRequestProviderError extends Schema.TaggedError<PullRequestProv
   {
     provider: SourceControlProviderKindSchema,
     operation: Schema.String,
-    reason: Schema.Literals(["missing-tool", "unauthenticated", "rate-limited", "failed"]),
+    reason: Schema.Literals([
+      "missing-tool",
+      "unauthenticated",
+      "rate-limited",
+      "not-found",
+      "failed",
+    ]),
     detail: Schema.String,
     retryAt: Schema.optional(Schema.Number),
     cause: Schema.optional(Schema.Defect()),
diff --git a/apps/server/src/pullRequest/PullRequestService.test.ts b/apps/server/src/pullRequest/PullRequestService.test.ts
index 7415ae45bfae518a5c4796043afc9ad5f6996c68..9a6b98ec399a510363491ca47d100f8d1fe6416f 100644
--- a/apps/server/src/pullRequest/PullRequestService.test.ts
+++ b/apps/server/src/pullRequest/PullRequestService.test.ts
@@ -4815,6 +4815,33 @@ it.effect("does not let a still-cached detail overwrite a fresher linked summary
   }),
 );
 
+it.effect("tells the client when the host has no pull request under that number", () =>
+  Effect.gen(function* () {
+    const reference = { projectId: "p1" as ProjectId, repository: "acme/web", number: 121 };
+    const service = yield* makeService({
+      projects: [project({ id: "p1", title: "web", workspaceRoot: "/a", repository: "acme/web" })],
+      providers: [
+        fakeProvider("github", {
+          getChangeRequest: () =>
+            Effect.fail(
+              new PullRequestProviderError({
+                provider: "github",
+                operation: "getChangeRequest",
+                reason: "not-found",
+                detail: "Pull request not found. Check the PR number or URL and try again.",
+              }),
+            ),
+        }),
+      ],
+    });
+
+    const error = yield* Effect.flip(service.detail(reference));
+
+    assert.strictEqual(error._tag, "PullRequestOperationError");
+    assert.strictEqual(error._tag === "PullRequestOperationError" && error.reason, "not-found");
+  }),
+);
+
 it.effect("keeps recent detail on a transient refresh failure but not after invalidation", () =>
   Effect.gen(function* () {
     let failing = false;
diff --git a/apps/server/src/pullRequest/PullRequestService.ts b/apps/server/src/pullRequest/PullRequestService.ts
index 293318f91c4bac4a6322badf8f4fcc0f089fbe5e..ec523d398237a17194e52ad9122cb0bed31f186a 100644
--- a/apps/server/src/pullRequest/PullRequestService.ts
+++ b/apps/server/src/pullRequest/PullRequestService.ts
@@ -477,7 +477,12 @@ function toPullRequestError(
   return (error) =>
     isProviderUnusable(error)
       ? toUnavailableError(error)
-      : new PullRequestOperationError({ operation, detail: error.detail, cause: error });
+      : new PullRequestOperationError({
+          operation,
+          detail: error.detail,
+          ...(error.reason === "not-found" ? { reason: "not-found" as const } : {}),
+          cause: error,
+        });
 }
 
 function withRateLimitBackoff(
diff --git a/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx b/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
index 5c82e03aa8ea8395ac68ad8aef52acff2cfd327b..bf5bd62de91ce8207d8acf9b302dd3c0725304c8 100644
--- a/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
+++ b/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
@@ -144,6 +144,7 @@ import {
   handoffReviewComments,
   latestPullRequestReviewOutcomes,
   loadingPullRequestCheckoutCommand,
+  isPullRequestNotFound,
   isStackedPullRequestBase,
   pullRequestActionMenuHasGroup,
   pullRequestActionNeedsHostRefresh,
@@ -2719,7 +2720,13 @@ export function PullRequestDetailPanel({
       >
         {detailQuery.error && !detail ? (
           <PullRequestsUnavailableState
-            error={detailQuery.error}
+            {...(isPullRequestNotFound(detailQuery.failure)
+              ? {
+                  title: `Pull request #${reference.number} not found`,
+                  error:
+                    "It may be an issue rather than a pull request, or this account can't see it.",
+                }
+              : { error: detailQuery.error })}
             refreshing={detailQuery.isPending}
             onRetry={refreshDetail}
             {...(unavailableGitHubUrl ? { gitHubUrl: unavailableGitHubUrl } : {})}
diff --git a/apps/web/src/components/pullRequest/pullRequestDetail.logic.ts b/apps/web/src/components/pullRequest/pullRequestDetail.logic.ts
index b8d2d897a4597f144aa571def0013f61d30772ac..cdca896e6074ce22172c9c47bf7022d00ab1eeb5 100644
--- a/apps/web/src/components/pullRequest/pullRequestDetail.logic.ts
+++ b/apps/web/src/components/pullRequest/pullRequestDetail.logic.ts
@@ -2,6 +2,7 @@ import * as Schema from "effect/Schema";
 
 import {
   PullRequestDetail,
+  PullRequestOperationError,
   pullRequestHostOf,
   type PullRequestAction,
   type PullRequestActor,
@@ -1161,6 +1162,12 @@ export function buildAddSelectionToAgentHandoff(input: {
   };
 }
 
+const isPullRequestOperationError = Schema.is(PullRequestOperationError);
+
+export function isPullRequestNotFound(failure: unknown): boolean {
+  return isPullRequestOperationError(failure) && failure.reason === "not-found";
+}
+
 /**
  * The internal wrapper every failed operation arrives in: which operation ran, and which tool
  * said no. A reader has no use for either.
diff --git a/apps/web/src/state/query.ts b/apps/web/src/state/query.ts
index ba081ffab1b7f4dc33f99fbb815f5345af6fa4fd..6a44c81049cb643ffa954b64393334adff937540 100644
--- a/apps/web/src/state/query.ts
+++ b/apps/web/src/state/query.ts
@@ -7,10 +7,11 @@ const EMPTY_ASYNC_RESULT_ATOM = Atom.make(AsyncResult.initial<never, never>(fals
   Atom.withLabel("web-environment-query:empty"),
 );
 
-export interface EnvironmentQueryView<A> {
+export interface EnvironmentQueryView<A, E = unknown> {
   readonly data: A | null;
   readonly dataUpdatedAt: number;
   readonly error: string | null;
+  readonly failure: E | null;
   readonly isPending: boolean;
   readonly isSuccess: boolean;
   readonly refresh: () => void;
@@ -25,7 +26,7 @@ export function formatEnvironmentQueryError(cause: Cause.Cause<unknown>): string
 
 export function useEnvironmentQuery<A, E>(
   atom: Atom.Atom<AsyncResult.AsyncResult<A, E>> | null,
-): EnvironmentQueryView<A> {
+): EnvironmentQueryView<A, E> {
   const selectedAtom = atom ?? EMPTY_ASYNC_RESULT_ATOM;
   const result = useAtomValue(selectedAtom);
   const refresh = useAtomRefresh(selectedAtom);
@@ -38,6 +39,8 @@ export function useEnvironmentQuery<A, E>(
           ? (Option.getOrNull(result.previousSuccess)?.timestamp ?? 0)
           : 0,
     error: result._tag === "Failure" ? formatEnvironmentQueryError(result.cause) : null,
+    failure:
+      result._tag === "Failure" ? Option.getOrNull(Cause.findErrorOption(result.cause)) : null,
     isPending: atom !== null && result.waiting,
     isSuccess: result._tag === "Success",
     refresh,
diff --git a/packages/contracts/src/pullRequest.ts b/packages/contracts/src/pullRequest.ts
index c8feaad9a41f2a0c9fa2a86b44e26608661b7145..b17d0141daef7802d84e5204ab2b59dcc082f6f5 100644
--- a/packages/contracts/src/pullRequest.ts
+++ b/packages/contracts/src/pullRequest.ts
@@ -1407,6 +1407,7 @@ export class PullRequestOperationError extends Schema.TaggedError<PullRequestOpe
   {
     operation: Schema.String,
     detail: TrimmedNonEmptyString,
+    reason: Schema.optional(Schema.Literal("not-found")),
     cause: Schema.optional(Schema.Defect()),
   },
   { httpApiStatus: 502 },
-- 
2.54.0