Guard PR merge queue queries behind feature detection

internal/featuredetection/feature_detection.go

@@ -24,12 +24,14 @@ type PullRequestFeatures struct {
 	ReviewDecision       bool
 	StatusCheckRollup    bool
 	BranchProtectionRule bool
+	MergeQueue           bool
 }
 
 var allPullRequestFeatures = PullRequestFeatures{
 	ReviewDecision:       true,
 	StatusCheckRollup:    true,
 	BranchProtectionRule: true,
+	MergeQueue:           true,
 }
 
 type RepositoryFeatures struct {
@@ -74,7 +76,34 @@ func (d *detector) PullRequestFeatures() (PullRequestFeatures, error) {
 		return allPullRequestFeatures, nil
 	}
 
-	return allPullRequestFeatures, nil
+	features := PullRequestFeatures{
+		ReviewDecision:       true,
+		StatusCheckRollup:    true,
+		BranchProtectionRule: true,
+	}
+
+	var featureDetection struct {
+		PullRequest struct {
+			Fields []struct {
+				Name string
+			} `graphql:"fields(includeDeprecated: true)"`
+		} `graphql:"PullRequest: __type(name: \"PullRequest\")"`
+	}
+
+	gql := graphql.NewClient(ghinstance.GraphQLEndpoint(d.host), d.httpClient)
+
+	err := gql.QueryNamed(context.Background(), "PullRequest_fields", &featureDetection, nil)
+	if err != nil {
+		return features, err
+	}
+
+	for _, field := range featureDetection.PullRequest.Fields {
+		if field.Name == "isInMergeQueue" {
+			features.MergeQueue = true
+		}
+	}
+
+	return features, nil
 }
 
 func (d *detector) RepositoryFeatures() (RepositoryFeatures, error) {

internal/featuredetection/feature_detection_test.go

@@ -24,16 +24,26 @@ func TestPullRequestFeatures(t *testing.T) {
 				ReviewDecision:       true,
 				StatusCheckRollup:    true,
 				BranchProtectionRule: true,
+				MergeQueue:           true,
 			},
 			wantErr: false,
 		},
 		{
 			name:     "GHE",
 			hostname: "git.my.org",
+			queryResponse: map[string]string{
+				`query PullRequest_fields\b`: heredoc.Doc(`
+					{ "data": { "PullRequest": { "fields": [
+						{"name": "isInMergeQueue"},
+						{"name": "isMergeQueueEnabled"}
+					] } } }
+				`),
+			},
 			wantFeatures: PullRequestFeatures{
 				ReviewDecision:       true,
 				StatusCheckRollup:    true,
 				BranchProtectionRule: true,
+				MergeQueue:           true,
 			},
 			wantErr: false,
 		},

pkg/cmd/pr/shared/finder.go

@@ -14,6 +14,7 @@ import (
 	"github.com/cli/cli/v2/api"
 	remotes "github.com/cli/cli/v2/context"
 	"github.com/cli/cli/v2/git"
+	fd "github.com/cli/cli/v2/internal/featuredetection"
 	"github.com/cli/cli/v2/internal/ghinstance"
 	"github.com/cli/cli/v2/internal/ghrepo"
 	"github.com/cli/cli/v2/pkg/cmdutil"
@@ -139,6 +140,18 @@ func (f *finder) Find(opts FindOptions) (*api.PullRequest, ghrepo.Interface, err
 	numberFieldOnly := fields.Len() == 1 && fields.Contains("number")
 	fields.Add("id") // for additional preload queries below
 
+	if fields.Contains("isInMergeQueue") || fields.Contains("isMergeQueueEnabled") {
+		detector := fd.NewDetector(httpClient, f.repo.RepoHost())
+		prFeatures, err := detector.PullRequestFeatures()
+		if err != nil {
+			return nil, nil, err
+		}
+		if !prFeatures.MergeQueue {
+			fields.Remove("isInMergeQueue")
+			fields.Remove("isMergeQueueEnabled")
+		}
+	}
+
 	var pr *api.PullRequest
 	if f.prNumber > 0 {
 		if numberFieldOnly {