Handle unsupported issueFieldValues enrichment in search_issues

pkg/github/issues.go

@@ -1967,9 +1967,9 @@ func fetchIssueReadEnrichment(ctx context.Context, gqlClient *githubv4.Client, n
 	return enrichment, nil
 }
 
-// searchIssuesHandler runs the REST issues search, enriches each hit with custom field values
-// fetched via a single follow-up GraphQL nodes() query, and applies any post-process options
-// (e.g. IFC labelling).
+// searchIssuesHandler runs the REST issues search, enriches each hit (best-effort) with custom
+// field values fetched via a single follow-up GraphQL nodes() query, and applies any post-process
+// options (e.g. IFC labelling).
 func searchIssuesHandler(ctx context.Context, deps ToolDependencies, args map[string]any, options ...searchOption) (*mcp.CallToolResult, error) {
 	const errorPrefix = "failed to search issues"
 
@@ -1996,15 +1996,18 @@ func searchIssuesHandler(ctx context.Context, deps ToolDependencies, args map[st
 		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, errorPrefix, resp, body), nil
 	}
 
+	// The field value enrichment is best-effort: a failure here (e.g. a server whose
+	// GraphQL schema predates the issueFieldValues field) must never fail the search.
 	var fieldValuesByID map[string][]MinimalFieldValue
 	if len(result.Issues) > 0 {
 		gqlClient, err := deps.GetGQLClient(ctx)
 		if err != nil {
-			return utils.NewToolResultErrorFromErr(errorPrefix+": failed to get GitHub GraphQL client", err), nil
-		}
-		fieldValuesByID, err = fetchIssueFieldValuesByNodeID(ctx, gqlClient, result.Issues)
-		if err != nil {
-			return ghErrors.NewGitHubGraphQLErrorResponse(ctx, errorPrefix+": failed to fetch issue field values", err), nil
+			_, _ = ghErrors.NewGitHubGraphQLErrorToCtx(ctx, errorPrefix+": failed to get GitHub GraphQL client", err)
+		} else {
+			fieldValuesByID, err = fetchIssueFieldValuesByNodeID(ctx, gqlClient, result.Issues)
+			if err != nil {
+				_, _ = ghErrors.NewGitHubGraphQLErrorToCtx(ctx, errorPrefix+": failed to fetch issue field values", err)
+			}
 		}
 	}
 

pkg/github/issues_test.go

@@ -1420,6 +1420,63 @@ func Test_SearchIssues_FieldValuesEnrichment(t *testing.T) {
 	assert.Empty(t, response.Items[1].FieldValues)
 }
 
+func Test_SearchIssues_FieldValuesEnrichmentUnsupported(t *testing.T) {
+	// Verify search_issues still returns its REST hits when the server's GraphQL
+	// schema does not support the issueFieldValues enrichment.
+	serverTool := SearchIssues(translations.NullTranslationHelper)
+
+	mockSearchResult := &github.IssuesSearchResult{
+		Total:             github.Ptr(1),
+		IncompleteResults: github.Ptr(false),
+		Issues: []*github.Issue{
+			{
+				Number:  github.Ptr(42),
+				Title:   github.Ptr("Bug: Something is broken"),
+				State:   github.Ptr("open"),
+				HTMLURL: github.Ptr("https://github.com/owner/repo/issues/42"),
+				NodeID:  github.Ptr("I_node_42"),
+				User:    &github.User{Login: github.Ptr("user1")},
+			},
+		},
+	}
+
+	restClient := MockHTTPClientWithHandlers(map[string]http.HandlerFunc{
+		GetSearchIssues: mockResponse(t, http.StatusOK, mockSearchResult),
+	})
+
+	gqlVars := map[string]any{
+		"ids": []any{"I_node_42"},
+	}
+	gqlResponse := githubv4mock.ErrorResponse("Field 'issueFieldValues' doesn't exist on type 'Issue'")
+
+	const nodesQueryString = "query($ids:[ID!]!){nodes(ids: $ids){... on Issue{id,issueFieldValues(first: 25){nodes{__typename,... on IssueFieldDateValue{field{... on IssueFieldDate{name,fullDatabaseId},... on IssueFieldNumber{name,fullDatabaseId},... on IssueFieldSingleSelect{name,fullDatabaseId},... on IssueFieldText{name,fullDatabaseId}},value},... on IssueFieldNumberValue{field{... on IssueFieldDate{name,fullDatabaseId},... on IssueFieldNumber{name,fullDatabaseId},... on IssueFieldSingleSelect{name,fullDatabaseId},... on IssueFieldText{name,fullDatabaseId}},valueNumber: value},... on IssueFieldSingleSelectValue{field{... on IssueFieldDate{name,fullDatabaseId},... on IssueFieldNumber{name,fullDatabaseId},... on IssueFieldSingleSelect{name,fullDatabaseId},... on IssueFieldText{name,fullDatabaseId}},value},... on IssueFieldTextValue{field{... on IssueFieldDate{name,fullDatabaseId},... on IssueFieldNumber{name,fullDatabaseId},... on IssueFieldSingleSelect{name,fullDatabaseId},... on IssueFieldText{name,fullDatabaseId}},value}}}}}}"
+	matcher := githubv4mock.NewQueryMatcher(nodesQueryString, gqlVars, gqlResponse)
+	gqlClient := githubv4.NewClient(githubv4mock.NewMockedHTTPClient(matcher))
+
+	deps := BaseDeps{
+		Client:    mustNewGHClient(t, restClient),
+		GQLClient: gqlClient,
+	}
+	handler := serverTool.Handler(deps)
+
+	request := createMCPRequest(map[string]any{
+		"query": "repo:owner/repo is:open",
+	})
+
+	result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+	require.NoError(t, err)
+	require.False(t, result.IsError, "expected result to not be an error")
+
+	textContent := getTextResult(t, result)
+
+	var response SearchIssuesResponse
+	require.NoError(t, json.Unmarshal([]byte(textContent.Text), &response))
+	require.Equal(t, 1, *response.Total)
+	require.Len(t, response.Items, 1)
+	assert.Equal(t, 42, *response.Items[0].Number)
+	assert.Empty(t, response.Items[0].FieldValues)
+}
+
 func Test_CreateIssue(t *testing.T) {
 	// Verify tool definition once
 	serverTool := IssueWrite(translations.NullTranslationHelper)