[fix] handle label creation race condition and log errors to Sentry instead of throwing (#2265)

## Summary

- Fix race condition in `ensureLabelExists` where concurrent requests
both get a 404, then both try to create the label, causing an
"already_exists" validation error
- Add `isLabelAlreadyExistsError` helper function to properly detect
GitHub's 422 validation error for duplicate labels
- Change error handling from throwing to logging to Sentry, preventing
the entire PR creation flow from failing due to label issues
- Update tests to verify new Sentry logging behavior and race condition
handling

  ## Problem

  When multiple concurrent requests call `ensureLabelExists`:
  1. Both check if label exists → both get 404
  2. Both try to create the label
3. First succeeds, second fails with
`{"resource":"Label","code":"already_exists","field":"name"}`
4. This error was thrown and caused the entire suggest-pr-changes flow
to fail

  ## Solution

- Catch the `already_exists` error during label creation and silently
ignore it (label exists, which is the desired state)
- Log other errors to Sentry instead of throwing, so label issues don't
block PR creation
FIxes CF-1017

js/cf-api/github/github-utils.ts

@@ -84,6 +84,16 @@ export async function getInstallationOctokitByOwner(
   }
 }
 
+function isLabelAlreadyExistsError(error: any): boolean {
+  return (
+    error?.status === 422 &&
+    Array.isArray(error?.response?.data?.errors) &&
+    error.response.data.errors.some(
+      (e: any) => e.resource === "Label" && e.code === "already_exists" && e.field === "name",
+    )
+  )
+}
+
 // Ensures that a label exists on a repository, creating it if it doesn't
 export async function ensureLabelExists(
   installationOctokit: Octokit,
@@ -102,16 +112,27 @@ export async function ensureLabelExists(
   } catch (error: any) {
     if (error.status === 404) {
       // Label does not exist, create it
-      await installationOctokit.rest.issues.createLabel({
-        owner,
-        repo,
-        name: labelName,
-        color,
-        description,
-      })
+      try {
+        await installationOctokit.rest.issues.createLabel({
+          owner,
+          repo,
+          name: labelName,
+          color,
+          description,
+        })
+      } catch (createError: any) {
+        // Ignore "already_exists" error - another concurrent request may have created it
+        if (!isLabelAlreadyExistsError(createError)) {
+          Sentry.captureException(createError, {
+            extra: { owner, repo, labelName, context: "ensureLabelExists - createLabel failed" },
+          })
+        }
+      }
     } else {
-      // An error occurred that wasn't a 404, rethrow it
-      throw error
+      // Log to Sentry and prevent throwing the error
+      Sentry.captureException(error, {
+        extra: { owner, repo, labelName, context: "ensureLabelExists - getLabel failed" },
+      })
     }
   }
 }

js/cf-api/github/tests/github-utils.unit.test.ts

@@ -1,12 +1,22 @@
 import { jest, describe, it, expect, beforeEach, afterEach } from "@jest/globals"
-import {
-  isUserCollaborator,
-  getInstallationOctokitByOwner,
+
+// Mock Sentry before importing modules that use it
+const mockCaptureException = jest.fn()
+jest.unstable_mockModule("@sentry/node", () => ({
+  captureException: mockCaptureException,
+  captureMessage: jest.fn(),
+  addBreadcrumb: jest.fn(),
+}))
+
+// Dynamic import after mock setup
+const {
   ensureLabelExists,
   addLabelToPullRequest,
+  isUserCollaborator,
+  getInstallationOctokitByOwner,
   setGithubUtilsDependencies,
   resetGithubUtilsDependencies,
-} from "../github-utils"
+} = await import("../github-utils.js")
 
 describe("GitHub Utils", () => {
   let mockOctokit: any
@@ -314,26 +324,7 @@ describe("GitHub Utils", () => {
       })
     })
 
-    it("should throw error for non-404 API errors", async () => {
-      const error = new Error("Internal Server Error")
-      ;(error as any).status = 500
-      ;(mockOctokit.rest.issues.getLabel as jest.MockedFunction<any>).mockRejectedValue(error)
-
-      await expect(
-        ensureLabelExists(
-          mockOctokit,
-          "test-owner",
-          "test-repo",
-          "test-label",
-          "FF0000",
-          "Test label description",
-        ),
-      ).rejects.toThrow("Internal Server Error")
-
-      expect(mockOctokit.rest.issues.createLabel).not.toHaveBeenCalled()
-    })
-
-    it("should handle label creation failure", async () => {
+    it("should log to Sentry on label creation failure instead of throwing", async () => {
       const getError = new Error("Not Found")
       ;(getError as any).status = 404
       ;(mockOctokit.rest.issues.getLabel as jest.MockedFunction<any>).mockRejectedValue(getError)
@@ -343,16 +334,51 @@ describe("GitHub Utils", () => {
         createError,
       )
 
-      await expect(
-        ensureLabelExists(
-          mockOctokit,
-          "test-owner",
-          "test-repo",
-          "test-label",
-          "FF0000",
-          "Test label description",
-        ),
-      ).rejects.toThrow("Label creation failed")
+      await ensureLabelExists(
+        mockOctokit,
+        "test-owner",
+        "test-repo",
+        "test-label",
+        "FF0000",
+        "Test label description",
+      )
+
+      expect(mockCaptureException).toHaveBeenCalledWith(createError, {
+        extra: {
+          owner: "test-owner",
+          repo: "test-repo",
+          labelName: "test-label",
+          context: "ensureLabelExists - createLabel failed",
+        },
+      })
+    })
+
+    it("should not log to Sentry when label already exists (race condition)", async () => {
+      const getError = new Error("Not Found")
+      ;(getError as any).status = 404
+      ;(mockOctokit.rest.issues.getLabel as jest.MockedFunction<any>).mockRejectedValue(getError)
+
+      const alreadyExistsError = new Error("Validation Failed")
+      ;(alreadyExistsError as any).status = 422
+      ;(alreadyExistsError as any).response = {
+        data: {
+          errors: [{ resource: "Label", code: "already_exists", field: "name" }],
+        },
+      }
+      ;(mockOctokit.rest.issues.createLabel as jest.MockedFunction<any>).mockRejectedValue(
+        alreadyExistsError,
+      )
+
+      await ensureLabelExists(
+        mockOctokit,
+        "test-owner",
+        "test-repo",
+        "test-label",
+        "FF0000",
+        "Test label description",
+      )
+
+      expect(mockCaptureException).not.toHaveBeenCalled()
     })
 
     it("should handle special characters in label name", async () => {
@@ -486,16 +512,27 @@ describe("GitHub Utils", () => {
       ).rejects.toThrow("Failed to add labels")
     })
 
-    it("should handle ensureLabelExists failure", async () => {
+    it("should continue to add labels even when ensureLabelExists logs error to Sentry", async () => {
       const error = new Error("Label operation failed")
       ;(error as any).status = 500
       ;(mockOctokit.rest.issues.getLabel as jest.MockedFunction<any>).mockRejectedValue(error)
 
-      await expect(
-        addLabelToPullRequest(mockOctokit, "test-owner", "test-repo", 123),
-      ).rejects.toThrow("Label operation failed")
+      await addLabelToPullRequest(mockOctokit, "test-owner", "test-repo", 123)
 
-      expect(mockOctokit.rest.issues.addLabels).not.toHaveBeenCalled()
+      expect(mockCaptureException).toHaveBeenCalledWith(error, {
+        extra: {
+          owner: "test-owner",
+          repo: "test-repo",
+          labelName: "⚡️ codeflash",
+          context: "ensureLabelExists - getLabel failed",
+        },
+      })
+      expect(mockOctokit.rest.issues.addLabels).toHaveBeenCalledWith({
+        owner: "test-owner",
+        repo: "test-repo",
+        issue_number: 123,
+        labels: ["⚡️ codeflash"],
+      })
     })
 
     it("should handle zero pull request number", async () => {