Resolve actor account type before applying allowed_bots (#1330)

ashwin-ant · web-flow · commit 1dc994ee7a00 · 2026-05-19T16:30:49.000-07:00
Move the allowed_bots check in checkHumanActor and checkWritePermissions so
it only fires after the actor has been resolved as a non-User account
(GitHub App / bot, or unresolvable app actor). Actors that resolve to a
regular User account go through the standard human/write checks regardless
of allowed_bots.

The Copilot-style path (GITHUB_ACTOR not ending in [bot] and not resolvable
as a user) is unchanged: it still falls through to the existing 404 catch,
which already consults allowed_bots once the API has reported the actor is
not a user.

Update tests to match and add coverage for the User-account path.
diff --git a/src/github/validation/actor.ts b/src/github/validation/actor.ts
@@ -32,35 +32,32 @@ export async function checkHumanActor(
   githubContext: GitHubContext,
 ) {
   const allowedBots = githubContext.inputs.allowedBots;
+  const actor = githubContext.actor;
 
-  // Check allowed_bots BEFORE calling the GitHub Users API.
-  // Some bot actors (e.g. GitHub Copilot with GITHUB_ACTOR="Copilot") are
-  // not resolvable via the Users API and would cause a 404 if we called it
-  // first.  By checking the allow-list early we avoid the unnecessary API
-  // call and the resulting crash.
-  if (isAllowedBot(githubContext.actor, allowedBots)) {
-    console.log(
-      `Actor ${githubContext.actor} is in allowed_bots list, skipping human actor check`,
-    );
-    return;
-  }
-
-  // Fetch user information from GitHub API
+  // Resolve the actor's account type before consulting allowed_bots so the
+  // allow-list only ever applies to non-User accounts. Some app actors
+  // (e.g. GitHub Copilot with GITHUB_ACTOR="Copilot") are not resolvable
+  // via the Users API and 404 — that path is handled in the catch below.
   let actorType: string;
   try {
     const { data: userData } = await octokit.users.getByUsername({
-      username: githubContext.actor,
+      username: actor,
     });
     actorType = userData.type;
   } catch (error) {
-    // Handle 404 for non-user actors (GitHub Apps whose GITHUB_ACTOR
-    // doesn't match any user account, e.g. "Copilot").
     if (
       error instanceof Error &&
       (error.message.includes("Not Found") ||
         error.message.includes("is not a user"))
     ) {
-      const botName = githubContext.actor.toLowerCase().replace(/\[bot\]$/, "");
+      // Unresolvable actors are GitHub Apps without a backing user account.
+      if (isAllowedBot(actor, allowedBots)) {
+        console.log(
+          `Actor ${actor} is in allowed_bots list, skipping human actor check`,
+        );
+        return;
+      }
+      const botName = actor.toLowerCase().replace(/\[bot\]$/, "");
       throw new Error(
         `Workflow initiated by non-human actor: ${botName} (actor not found on GitHub). Add bot to allowed_bots list or use '*' to allow all bots.`,
       );
@@ -70,15 +67,22 @@ export async function checkHumanActor(
 
   console.log(`Actor type: ${actorType}`);
 
-  // Check bot permissions if actor is not a User
   if (actorType !== "User") {
-    const botName = githubContext.actor.toLowerCase().replace(/\[bot\]$/, "");
-
-    // Bot not allowed (we already checked allowed_bots above)
+    // GitHub Apps and other bot accounts.
+    if (isAllowedBot(actor, allowedBots)) {
+      console.log(
+        `Actor ${actor} is in allowed_bots list, skipping human actor check`,
+      );
+      return;
+    }
+    const botName = actor.toLowerCase().replace(/\[bot\]$/, "");
     throw new Error(
       `Workflow initiated by non-human actor: ${botName} (type: ${actorType}). Add bot to allowed_bots list or use '*' to allow all bots.`,
     );
   }
 
-  console.log(`Verified human actor: ${githubContext.actor}`);
+  // Regular User account. allowed_bots is only for bot actors and is not
+  // consulted here; write-access enforcement for users happens separately
+  // in checkWritePermissions.
+  console.log(`Verified human actor: ${actor}`);
 }
diff --git a/src/github/validation/permissions.ts b/src/github/validation/permissions.ts
@@ -66,22 +66,19 @@ export async function checkWritePermissions(
       }
     }
 
-    // Check if the actor is a GitHub App (bot user with [bot] suffix)
+    // Check if the actor is a GitHub App (bot user with [bot] suffix).
+    // Usernames cannot contain "[" or "]", so the suffix is a reliable
+    // bot signal that doesn't require an API lookup.
     if (actor.endsWith("[bot]")) {
       core.info(`Actor is a GitHub App: ${actor}`);
       return true;
     }
 
-    // Check if the actor is in the allowed bots list (handles non-[bot] actors
-    // like GitHub Copilot whose GITHUB_ACTOR is "Copilot", not "Copilot[bot]")
-    if (isAllowedBot(actor, allowedBots)) {
-      core.info(
-        `Actor ${actor} is in allowed_bots list, skipping permission check`,
-      );
-      return true;
-    }
-
-    // Check permissions directly using the permission endpoint
+    // For all other actors, resolve the account via the collaborator
+    // permission endpoint. allowed_bots is only consulted in the catch
+    // block below, after the API has confirmed the actor is not a regular
+    // user account (e.g. GitHub Apps like Copilot whose GITHUB_ACTOR is
+    // "Copilot" rather than "Copilot[bot]").
     const response = await octokit.repos.getCollaboratorPermissionLevel({
       owner: repository.owner,
       repo: repository.repo,
diff --git a/test/actor.test.ts b/test/actor.test.ts
@@ -97,7 +97,8 @@ describe("checkHumanActor", () => {
   describe("non-[bot] actors (e.g. GitHub Copilot)", () => {
     // GitHub Copilot SWE Agent sets GITHUB_ACTOR="Copilot" which is not a
     // valid GitHub user and doesn't end with [bot], causing 404 on the
-    // Users API. These tests verify the fix handles this gracefully.
+    // Users API. allowed_bots is applied once the API has resolved the
+    // actor as not being a regular user account.
 
     function createMockOctokitThat404s(): Octokit {
       return {
@@ -117,7 +118,6 @@ describe("checkHumanActor", () => {
       context.actor = "Copilot";
       context.inputs.allowedBots = "copilot,cursor";
 
-      // Should not even call the API — allowed_bots check happens first
       await expect(
         checkHumanActor(mockOctokit, context),
       ).resolves.toBeUndefined();
@@ -167,4 +167,52 @@ describe("checkHumanActor", () => {
       ).resolves.toBeUndefined();
     });
   });
+
+  describe("account type resolution", () => {
+    // The Users API resolves the actor's account type before allowed_bots
+    // is consulted. allowed_bots is only relevant for Bot accounts and
+    // unresolvable app actors; it does not change behavior for regular
+    // User accounts.
+
+    test("should pass for a User account whose name matches allowed_bots", async () => {
+      const mockOctokit = createMockOctokit("User");
+      const context = createMockContext();
+      context.actor = "renovate";
+      context.inputs.allowedBots = "renovate";
+
+      await expect(
+        checkHumanActor(mockOctokit, context),
+      ).resolves.toBeUndefined();
+    });
+
+    test("should pass for a User account when allowed_bots is '*'", async () => {
+      const mockOctokit = createMockOctokit("User");
+      const context = createMockContext();
+      context.actor = "some-user";
+      context.inputs.allowedBots = "*";
+
+      await expect(
+        checkHumanActor(mockOctokit, context),
+      ).resolves.toBeUndefined();
+    });
+
+    test("should resolve account type even when actor name appears in allowed_bots", async () => {
+      // The Users API call should not be short-circuited by allowed_bots,
+      // so an unexpected API error propagates instead of being swallowed.
+      const mockOctokit = {
+        users: {
+          getByUsername: async () => {
+            throw new Error("Internal Server Error");
+          },
+        },
+      } as unknown as Octokit;
+      const context = createMockContext();
+      context.actor = "some-user";
+      context.inputs.allowedBots = "some-user";
+
+      await expect(checkHumanActor(mockOctokit, context)).rejects.toThrow(
+        "Internal Server Error",
+      );
+    });
+  });
 });
diff --git a/test/permissions.test.ts b/test/permissions.test.ts
@@ -307,7 +307,9 @@ describe("checkWritePermissions", () => {
   describe("non-[bot] actors (e.g. GitHub Copilot)", () => {
     // GitHub Copilot SWE Agent sets GITHUB_ACTOR="Copilot" which doesn't
     // end with [bot] and is not a valid GitHub user, so the collaborator
-    // permission API returns 404 with "is not a user".
+    // permission API returns 404 with "is not a user". allowed_bots is
+    // applied in that catch path once the API has confirmed the actor is
+    // not a regular user account.
 
     const createMockOctokitThat404s = () =>
       ({
@@ -322,9 +324,7 @@ describe("checkWritePermissions", () => {
         },
       }) as any;
 
-    test("should return true for non-[bot] actor in allowed_bots (pre-API check)", async () => {
-      // The allowed_bots check should happen BEFORE calling the API,
-      // so this should succeed even with a 404-ing mock.
+    test("should return true for non-[bot] app actor in allowed_bots", async () => {
       const mockOctokit = createMockOctokitThat404s();
       const context = createContext();
       context.actor = "Copilot";
@@ -334,11 +334,11 @@ describe("checkWritePermissions", () => {
 
       expect(result).toBe(true);
       expect(coreInfoSpy).toHaveBeenCalledWith(
-        "Actor Copilot is in allowed_bots list, skipping permission check",
+        "Non-user actor Copilot is in allowed_bots list, granting access",
       );
     });
 
-    test("should return true for non-[bot] actor when allowed_bots is '*' (pre-API check)", async () => {
+    test("should return true for non-[bot] app actor when allowed_bots is '*'", async () => {
       const mockOctokit = createMockOctokitThat404s();
       const context = createContext();
       context.actor = "Copilot";
@@ -349,20 +349,18 @@ describe("checkWritePermissions", () => {
       expect(result).toBe(true);
     });
 
-    test("should return true for non-[bot] actor in allowed_bots via 404 fallback", async () => {
-      // Even if somehow we reach the API call (e.g. race condition or
-      // future refactor), the 404 catch path should also check allowed_bots.
+    test("should match config entries written with the [bot] suffix", async () => {
       const mockOctokit = createMockOctokitThat404s();
       const context = createContext();
       context.actor = "SomeNewBot";
-      context.inputs.allowedBots = "somenewbot";
+      context.inputs.allowedBots = "somenewbot[bot]";
 
       const result = await checkWritePermissions(mockOctokit, context);
 
       expect(result).toBe(true);
     });
 
-    test("should return false for non-[bot] actor that 404s and is not in allowed_bots", async () => {
+    test("should return false for non-[bot] app actor that is not in allowed_bots", async () => {
       const mockOctokit = createMockOctokitThat404s();
       const context = createContext();
       context.actor = "Copilot";
@@ -376,7 +374,7 @@ describe("checkWritePermissions", () => {
       );
     });
 
-    test("should return false for non-[bot] actor that 404s with empty allowed_bots", async () => {
+    test("should return false for non-[bot] app actor with empty allowed_bots", async () => {
       const mockOctokit = createMockOctokitThat404s();
       const context = createContext();
       context.actor = "Copilot";
@@ -404,4 +402,57 @@ describe("checkWritePermissions", () => {
       );
     });
   });
+
+  describe("allowed_bots only applies to non-user actors", () => {
+    // The permission endpoint resolves the actor's account type. Actors
+    // that resolve to a regular user account go through the standard write
+    // permission check; allowed_bots does not short-circuit it for them.
+
+    test("should require write permission for a user account whose name matches allowed_bots", async () => {
+      const mockOctokit = createMockOctokit("read");
+      const context = createContext();
+      context.actor = "renovate";
+      context.inputs.allowedBots = "renovate";
+
+      const result = await checkWritePermissions(mockOctokit, context);
+
+      expect(result).toBe(false);
+      expect(coreWarningSpy).toHaveBeenCalledWith(
+        "Actor has insufficient permissions: read",
+      );
+    });
+
+    test("should require write permission for a user account when allowed_bots uses the [bot] form", async () => {
+      const mockOctokit = createMockOctokit("read");
+      const context = createContext();
+      context.actor = "renovate";
+      context.inputs.allowedBots = "renovate[bot]";
+
+      const result = await checkWritePermissions(mockOctokit, context);
+
+      expect(result).toBe(false);
+    });
+
+    test("should require write permission for a user account when allowed_bots is '*'", async () => {
+      const mockOctokit = createMockOctokit("none");
+      const context = createContext();
+      context.actor = "some-user";
+      context.inputs.allowedBots = "*";
+
+      const result = await checkWritePermissions(mockOctokit, context);
+
+      expect(result).toBe(false);
+    });
+
+    test("should still grant access for a user account with write permission", async () => {
+      const mockOctokit = createMockOctokit("write");
+      const context = createContext();
+      context.actor = "renovate";
+      context.inputs.allowedBots = "renovate";
+
+      const result = await checkWritePermissions(mockOctokit, context);
+
+      expect(result).toBe(true);
+    });
+  });
 });
