fix(pullrequests): return warning instead of error on label addition failure in create_pull_request

- Add optional `Warning` field to `MinimalResponse` to allow propagating non-blocking warnings on successful operations.
- Update `create_pull_request` to return a successful tool response with a warning if PR creation succeeds but label addition fails, resolving the retry hazard.
- Correct unit tests to mock `422` (Unprocessable Entity) instead of `404` for label addition failure, and assert the warning field.
- Update description of the `labels` parameter in schema to clarify that labels must already exist in the repository.

Author: “yashdesai30”

pkg/github/__toolsnaps__/create_pull_request.snap

@@ -31,7 +31,7 @@
         "type": "string"
       },
       "labels": {
-        "description": "Labels to apply to this pull request",
+        "description": "Labels to apply to this pull request (must already exist in the repository)",
         "items": {
           "type": "string"
         },

pkg/github/minimal_types.go

@@ -134,8 +134,9 @@ type MinimalTag struct {
 // Success is implicit in the HTTP response status, and all other information
 // can be derived from the URL or fetched separately if needed.
 type MinimalResponse struct {
-	ID  string `json:"id"`
-	URL string `json:"url"`
+	ID      string `json:"id"`
+	URL     string `json:"url"`
+	Warning string `json:"warning,omitempty"`
 }
 
 type MinimalProject struct {

pkg/github/pullrequests.go

@@ -589,7 +589,7 @@ func CreatePullRequest(t translations.TranslationHelperFunc) inventory.ServerToo
 					"labels": {
 						Type:        "array",
 						Items:       &jsonschema.Schema{Type: "string"},
-						Description: "Labels to apply to this pull request",
+						Description: "Labels to apply to this pull request (must already exist in the repository)",
 					},
 				},
 				Required: []string{"owner", "repo", "title", "head", "base"},
@@ -693,15 +693,12 @@ func CreatePullRequest(t translations.TranslationHelperFunc) inventory.ServerToo
 				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to create pull request", resp, bodyBytes), nil, nil
 			}
 
+			var warningMsg string
 			// Add labels if provided
 			if len(labels) > 0 {
 				_, labelsResp, labelsErr := client.Issues.AddLabelsToIssue(ctx, owner, repo, pr.GetNumber(), labels)
 				if labelsErr != nil {
-					return ghErrors.NewGitHubAPIErrorResponse(ctx,
-						fmt.Sprintf("pull request created (#%d) but failed to add labels", pr.GetNumber()),
-						labelsResp,
-						labelsErr,
-					), nil, nil
+					warningMsg = fmt.Sprintf("pull request created (#%d) but failed to add labels: %s", pr.GetNumber(), labelsErr.Error())
 				}
 				if labelsResp != nil {
 					_ = labelsResp.Body.Close()
@@ -710,8 +707,9 @@ func CreatePullRequest(t translations.TranslationHelperFunc) inventory.ServerToo
 
 			// Return minimal response with just essential information
 			minimalResponse := MinimalResponse{
-				ID:  fmt.Sprintf("%d", pr.GetID()),
-				URL: pr.GetHTMLURL(),
+				ID:      fmt.Sprintf("%d", pr.GetID()),
+				URL:     pr.GetHTMLURL(),
+				Warning: warningMsg,
 			}
 
 			r, err := json.Marshal(minimalResponse)

pkg/github/pullrequests_test.go

@@ -2207,12 +2207,13 @@ func Test_CreatePullRequest(t *testing.T) {
 	}
 
 	tests := []struct {
-		name           string
-		mockedClient   *http.Client
-		requestArgs    map[string]any
-		expectError    bool
-		expectedPR     *github.PullRequest
-		expectedErrMsg string
+		name            string
+		mockedClient    *http.Client
+		requestArgs     map[string]any
+		expectError     bool
+		expectedPR      *github.PullRequest
+		expectedErrMsg  string
+		expectedWarning string
 	}{
 		{
 			name: "successful PR creation",
@@ -2295,7 +2296,7 @@ func Test_CreatePullRequest(t *testing.T) {
 			mockedClient: MockHTTPClientWithHandlers(map[string]http.HandlerFunc{
 				PostReposPullsByOwnerByRepo: mockResponse(t, http.StatusCreated, mockPR),
 				PostReposIssuesLabelsByOwnerByRepoByIssueNumber: http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-					w.WriteHeader(http.StatusNotFound)
+					w.WriteHeader(http.StatusUnprocessableEntity)
 					_, _ = w.Write([]byte(`{"message": "Label does not exist"}`))
 				}),
 			}),
@@ -2307,8 +2308,9 @@ func Test_CreatePullRequest(t *testing.T) {
 				"base":   "main",
 				"labels": []any{"nonexistent-label"},
 			},
-			expectError:    true,
-			expectedErrMsg: "failed to add labels",
+			expectError:     false,
+			expectedPR:      mockPR,
+			expectedWarning: "pull request created (#42) but failed to add labels",
 		},
 	}
 
@@ -2351,6 +2353,12 @@ func Test_CreatePullRequest(t *testing.T) {
 			err = json.Unmarshal([]byte(textContent.Text), &returnedPR)
 			require.NoError(t, err)
 			assert.Equal(t, tc.expectedPR.GetHTMLURL(), returnedPR.URL)
+
+			if tc.expectedWarning != "" {
+				assert.Contains(t, returnedPR.Warning, tc.expectedWarning)
+			} else {
+				assert.Empty(t, returnedPR.Warning)
+			}
 		})
 	}
 }