feat(pull-requests): open native Gitea revert pull requests

apps/server/src/pullRequest/GiteaPullRequestApi.test.ts

@@ -150,6 +150,39 @@ layer("GiteaPullRequestApi", (it) => {
     expect(yield* api.getAutoMergeEnabled({host: "forge.example.test", repository: "acme/web", number: 7})).toBe(true);
     expect(callAt(1).path).toContain("/timeline?");
   }));
+  it.effect("opens a native revert PR only on an advertising Gitea server", () =>
+    Effect.gen(function* () {
+      mockedRequest
+        .mockReturnValueOnce(Effect.succeed(response({ features: ["pull-revert"] })))
+        .mockReturnValueOnce(Effect.succeed(response(rawPullRequest(8))));
+      const api = yield* GiteaPullRequestApi.make;
+      yield* api.runAction({
+        host: "forge.example.test",
+        repository: "acme/web",
+        number: 7,
+        action: "revert",
+      });
+      expect(callAt(1)).toMatchObject({ method: "POST", path: "/repos/acme/web/pulls/7/revert" });
+      expect(mockedRequest.mock.calls).toHaveLength(2);
+    }),
+  );
+  it.effect("does not attempt a revert on stock Gitea", () =>
+    Effect.gen(function* () {
+      mockedRequest.mockReturnValueOnce(Effect.succeed(response({ features: [] })));
+      const api = yield* GiteaPullRequestApi.make;
+      const error = yield* api
+        .runAction({
+          host: "forge.example.test",
+          repository: "acme/web",
+          number: 7,
+          action: "revert",
+        })
+        .pipe(Effect.flip);
+      expect(error.detail).toContain("does not expose native pull request reverts");
+      expect(mockedRequest.mock.calls.every(([call]) => call.method === "GET")).toBe(true);
+    }),
+  );
+
   it.effect("approves only the current pull request's waiting workflow runs", () =>
     Effect.gen(function* () {
       const pull = rawPullRequest(7);

apps/server/src/pullRequest/GiteaPullRequestApi.ts

@@ -1631,12 +1631,25 @@ export const make = Effect.gen(function* () {
     },
   );
 
-  const unsupportedAction = (action: string) =>
-    new GiteaPullRequestApiError({
-      operation: "runAction",
-      reason: "failed",
-      detail: `Gitea does not expose a reliable ${action} operation through this API.`,
+  const revertPullRequest = Effect.fn("GiteaPullRequestApi.revertPullRequest")(function* (input: {
+    host: string;
+    repository: string;
+    number: number;
+  }) {
+    yield* validateHost(input.host);
+    if (!(yield* getFeatures).includes("pull-revert"))
+      return yield* new GiteaPullRequestApiError({
+        operation: "revertPullRequest",
+        reason: "failed",
+        detail: "This Gitea server does not expose native pull request reverts.",
+      });
+    return yield* write({
+      operation: "revertPullRequest",
+      ...input,
+      method: "POST",
+      path: `${basePath(input.repository)}/pulls/${input.number}/revert`,
     });
+  });
 
   return GiteaPullRequestApi.of({
     getFeatures: () => getFeatures,
@@ -1833,7 +1846,7 @@ export const make = Effect.gen(function* () {
         case "approve-workflows":
           return approveWorkflows(input);
         case "revert":
-          return Effect.fail(unsupportedAction(input.action));
+          return revertPullRequest(input);
       }
     },
     updatePullRequest: (input) =>

apps/server/src/pullRequest/GiteaPullRequestProvider.test.ts

@@ -166,3 +166,19 @@ describe("giteaProviderFailure", () => {
     ).toEqual({ reason: "rate-limited", retryAt: 1234 });
   });
 });
+
+describe("native revert permission", () => {
+  it("requires write access and the advertised native endpoint", () => {
+    const input = { canWrite: true, ownsPullRequest: false, updateMethods: [] as const };
+    expect(giteaViewerPermissions(input).actions).not.toContain("revert");
+    expect(giteaViewerPermissions({ ...input, revertSupported: true }).actions).toContain("revert");
+    expect(
+      giteaViewerPermissions({
+        ...input,
+        canWrite: false,
+        ownsPullRequest: true,
+        revertSupported: true,
+      }).actions,
+    ).not.toContain("revert");
+  });
+});

apps/server/src/pullRequest/GiteaPullRequestProvider.ts

@@ -25,6 +25,7 @@ const CAPABILITIES: PullRequestCapabilities = {
     "enable-auto-merge",
     "disable-auto-merge",
     "approve-workflows",
+    "revert",
   ],
   mergeMethods: ["merge", "squash", "rebase"],
   updateMethods: ["merge", "rebase"],
@@ -66,11 +67,13 @@ export function giteaProviderFailure(
 export function giteaViewerPermissions(input: {
   readonly canWrite: boolean;
   readonly workflowApprovalSupported?: boolean;
+  readonly revertSupported?: boolean;
   readonly ownsPullRequest: boolean;
   readonly updateMethods: ReadonlyArray<"merge" | "rebase">;
 }): PullRequestViewerPermissions {
   return {
     actions: CAPABILITIES.actions.filter((action) => {
+      if (action === "revert") return input.canWrite && input.revertSupported === true;
       if (action === "approve-workflows")
         return input.canWrite && input.workflowApprovalSupported === true;
       if (action === "ready" || action === "draft" || action === "close" || action === "reopen")
@@ -137,10 +140,12 @@ export const make = Effect.gen(function* () {
     readonly viewer: string;
     readonly author: string | undefined;
     readonly workflowApprovalSupported?: boolean;
+    readonly revertSupported?: boolean;
   }) =>
     giteaViewerPermissions({
       canWrite: input.access.canWrite,
       workflowApprovalSupported: input.workflowApprovalSupported,
+      revertSupported: input.revertSupported,
       ownsPullRequest:
         input.author !== undefined && input.author.toLowerCase() === input.viewer.toLowerCase(),
       updateMethods: input.access.updateMethods,
@@ -190,10 +195,11 @@ export const make = Effect.gen(function* () {
           api
             .getWorkflowApprovals(input)
             .pipe(Effect.orElseSucceed(() => ({ supported: false, runs: [] }))),
+          api.getFeatures().pipe(Effect.orElseSucceed(() => [])),
         ],
         { concurrency: 4 },
       ).pipe(
-        Effect.flatMap(([pullRequest, access, viewer, autoMergeEnabled, workflows]) =>
+        Effect.flatMap(([pullRequest, access, viewer, autoMergeEnabled, workflows, features]) =>
           api.listChecks({ ...input, sha: pullRequest.headSha }).pipe(
             Effect.orElseSucceed(() => []),
             Effect.map((checks): ProviderChangeRequestDetail => ({
@@ -224,6 +230,7 @@ export const make = Effect.gen(function* () {
                 viewer,
                 author: pullRequest.author?.login,
                 workflowApprovalSupported: workflows.supported,
+                revertSupported: features.includes("pull-revert"),
               }),
             })),
           ),
@@ -332,6 +339,7 @@ export const make = Effect.gen(function* () {
             viewer,
             author: pullRequest.author?.login,
             workflowApprovalSupported: features.includes("actions-run-approve"),
+            revertSupported: features.includes("pull-revert"),
           }),
         ),
       ),