[gh release create] Fail when there are no new commits since the most recent release

pkg/cmd/release/create/create.go

@@ -60,6 +60,7 @@ type CreateOptions struct {
 	NotesStartTag      string
 	VerifyTag          bool
 	NotesFromTag       bool
+	OnlyNew            bool
 }
 
 func NewCmdCreate(f *cmdutil.Factory, runF func(*CreateOptions) error) *cobra.Command {
@@ -194,6 +195,7 @@ func NewCmdCreate(f *cmdutil.Factory, runF func(*CreateOptions) error) *cobra.Co
 	cmdutil.NilBoolFlag(cmd, &opts.IsLatest, "latest", "", "Mark this release as \"Latest\" (default [automatic based on date and version]). --latest=false to explicitly NOT set as latest")
 	cmd.Flags().BoolVarP(&opts.VerifyTag, "verify-tag", "", false, "Abort in case the git tag doesn't already exist in the remote repository")
 	cmd.Flags().BoolVarP(&opts.NotesFromTag, "notes-from-tag", "", false, "Automatically generate notes from annotated tag")
+	cmd.Flags().BoolVar(&opts.OnlyNew, "only-new", false, "Create release only if there are new commits since the last release")
 
 	_ = cmdutil.RegisterBranchCompletionFlags(f.GitClient, cmd, "target")
 
@@ -211,6 +213,16 @@ func createRun(opts *CreateOptions) error {
 		return err
 	}
 
+	if opts.OnlyNew {
+		isNew, err := isNewRelease(httpClient, baseRepo)
+		if err != nil {
+			return err
+		}
+		if !isNew {
+			return fmt.Errorf("no new commits since the last release")
+		}
+	}
+
 	var existingTag bool
 	if opts.TagName == "" {
 		tags, err := getTags(httpClient, baseRepo, 5)

pkg/cmd/release/create/create_test.go

@@ -63,6 +63,7 @@ func Test_NewCmdCreate(t *testing.T) {
 				Concurrency:  5,
 				Assets:       []*shared.AssetForUpload(nil),
 				VerifyTag:    false,
+				OnlyNew:      false,
 			},
 		},
 		{
@@ -87,6 +88,7 @@ func Test_NewCmdCreate(t *testing.T) {
 				Concurrency:  5,
 				Assets:       []*shared.AssetForUpload(nil),
 				VerifyTag:    false,
+				OnlyNew:      false,
 			},
 		},
 		{
@@ -347,6 +349,19 @@ func Test_NewCmdCreate(t *testing.T) {
 			isTTY:   false,
 			wantErr: "using `--notes-from-tag` with `--generate-notes` or `--notes-start-tag` is not supported",
 		},
+		{
+			name:  "with --only-new",
+			args:  "v1.2.3 --only-new",
+			isTTY: false,
+			want: CreateOptions{
+				TagName:      "v1.2.3",
+				BodyProvided: false,
+				Concurrency:  5,
+				Assets:       []*shared.AssetForUpload(nil),
+				NotesFromTag: false,
+				OnlyNew:      true,
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -402,6 +417,7 @@ func Test_NewCmdCreate(t *testing.T) {
 			assert.Equal(t, tt.want.IsLatest, opts.IsLatest)
 			assert.Equal(t, tt.want.VerifyTag, opts.VerifyTag)
 			assert.Equal(t, tt.want.NotesFromTag, opts.NotesFromTag)
+			assert.Equal(t, tt.want.OnlyNew, opts.OnlyNew)
 
 			require.Equal(t, len(tt.want.Assets), len(opts.Assets))
 			for i := range tt.want.Assets {
@@ -460,6 +476,100 @@ func Test_createRun(t *testing.T) {
 			wantStdout: "https://github.com/OWNER/REPO/releases/tag/v1.2.3\n",
 			wantStderr: ``,
 		},
+		{
+			name:  "create a release if there are new commits and the last release does not exist",
+			isTTY: true,
+			opts: CreateOptions{
+				TagName:      "v1.2.3",
+				Name:         "The Big 1.2",
+				Body:         "* Fixed bugs",
+				BodyProvided: true,
+				Target:       "",
+				OnlyNew:      true,
+			},
+			runStubs: defaultRunStubs,
+			httpStubs: func(t *testing.T, reg *httpmock.Registry) {
+				reg.Register(httpmock.REST("GET", "repos/OWNER/REPO/releases/latest"), httpmock.StatusStringResponse(404, `{
+					"message": "Not Found",
+					"documentation_url": "https://docs.github.com/rest/releases/releases#get-the-latest-release",
+					"status": "404"
+				}`))
+				reg.Register(httpmock.REST("POST", "repos/OWNER/REPO/releases"), httpmock.RESTPayload(201, `{
+					"url": "https://api.github.com/releases/123",
+					"upload_url": "https://api.github.com/assets/upload",
+					"html_url": "https://github.com/OWNER/REPO/releases/tag/v1.2.3"
+				}`, func(params map[string]interface{}) {
+					assert.Equal(t, map[string]interface{}{
+						"tag_name":   "v1.2.3",
+						"name":       "The Big 1.2",
+						"body":       "* Fixed bugs",
+						"draft":      false,
+						"prerelease": false,
+					}, params)
+				}))
+			},
+			wantStdout: "https://github.com/OWNER/REPO/releases/tag/v1.2.3\n",
+			wantStderr: ``,
+		},
+		{
+			name:  "create a release if there are new commits and the last release exists",
+			isTTY: true,
+			opts: CreateOptions{
+				TagName:      "v1.2.3",
+				Name:         "The Big 1.2",
+				Body:         "* Fixed bugs",
+				BodyProvided: true,
+				Target:       "",
+				OnlyNew:      true,
+			},
+			runStubs: defaultRunStubs,
+			httpStubs: func(t *testing.T, reg *httpmock.Registry) {
+				reg.Register(httpmock.REST("GET", "repos/OWNER/REPO/releases/latest"), httpmock.StatusStringResponse(200, `{
+					"tag_name": "v1.2.2"
+				}`))
+				reg.Register(httpmock.REST("GET", "repos/OWNER/REPO/compare/v1.2.2...HEAD"), httpmock.StatusStringResponse(200, `{
+						"status": "ahead"
+				}`))
+				reg.Register(httpmock.REST("POST", "repos/OWNER/REPO/releases"), httpmock.RESTPayload(201, `{
+					"url": "https://api.github.com/releases/123",
+					"upload_url": "https://api.github.com/assets/upload",
+					"html_url": "https://github.com/OWNER/REPO/releases/tag/v1.2.3"
+				}`, func(params map[string]interface{}) {
+					assert.Equal(t, map[string]interface{}{
+						"tag_name":   "v1.2.3",
+						"name":       "The Big 1.2",
+						"body":       "* Fixed bugs",
+						"draft":      false,
+						"prerelease": false,
+					}, params)
+				}))
+			},
+			wantStdout: "https://github.com/OWNER/REPO/releases/tag/v1.2.3\n",
+			wantStderr: ``,
+		},
+		{
+			name:  "create a release if there are no new commits but the last release exists",
+			isTTY: true,
+			opts: CreateOptions{
+				TagName:      "v1.2.3",
+				Name:         "The Big 1.2",
+				Body:         "* Fixed bugs",
+				BodyProvided: true,
+				Target:       "",
+				OnlyNew:      true,
+			},
+			httpStubs: func(t *testing.T, reg *httpmock.Registry) {
+				reg.Register(httpmock.REST("GET", "repos/OWNER/REPO/releases/latest"), httpmock.StatusStringResponse(200, `{
+					"tag_name": "v1.2.2"
+				}`))
+				reg.Register(httpmock.REST("GET", "repos/OWNER/REPO/compare/v1.2.2...HEAD"), httpmock.StatusStringResponse(200, `{
+					"status": "identical"
+				}`))
+			},
+			wantErr:    "no new commits since the last release",
+			wantStdout: "",
+			wantStderr: ``,
+		},
 		{
 			name:  "with discussion category",
 			isTTY: true,

pkg/cmd/release/create/http.go

@@ -2,6 +2,7 @@ package create
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -299,3 +300,48 @@ func tokenHasWorkflowScope(resp *http.Response) bool {
 
 	return slices.Contains(strings.Split(scopes, ","), "workflow")
 }
+
+// isNewRelease checks if there are new commits since the latest release.
+func isNewRelease(httpClient *http.Client, repo ghrepo.Interface) (bool, error) {
+	ctx := context.Background()
+	release, err := shared.FetchLatestRelease(ctx, httpClient, repo)
+	if err != nil {
+		if errors.Is(err, shared.ErrReleaseNotFound) {
+			return true, nil
+		} else {
+			return false, err
+		}
+	}
+
+	tagName := release.TagName
+	path := fmt.Sprintf("repos/%s/%s/compare/%s...HEAD?per_page=1", repo.RepoOwner(), repo.RepoName(), tagName)
+	url := ghinstance.RESTPrefix(repo.RepoHost()) + path
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return false, err
+	}
+
+	req.Header.Set("Content-Type", "application/json; charset=utf-8")
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return false, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return false, api.HandleHTTPError(resp)
+	}
+
+	type comparisonStatus struct {
+		Status string `json:"status"`
+	}
+
+	var cmpStatus comparisonStatus
+	if err := json.NewDecoder(resp.Body).Decode(&cmpStatus); err != nil {
+		return false, err
+	}
+
+	isNew := cmpStatus.Status == "ahead"
+	return isNew, nil
+}

pkg/cmd/release/shared/fetch.go

@@ -124,7 +124,7 @@ func (rel *Release) ExportData(fields []string) map[string]interface{} {
 	return data
 }
 
-var errNotFound = errors.New("release not found")
+var ErrReleaseNotFound = errors.New("release not found")
 
 type fetchResult struct {
 	release *Release
@@ -150,7 +150,7 @@ func FetchRelease(ctx context.Context, httpClient *http.Client, repo ghrepo.Inte
 	}()
 
 	res := <-results
-	if errors.Is(res.error, errNotFound) {
+	if errors.Is(res.error, ErrReleaseNotFound) {
 		res = <-results
 		cancel() // satisfy the linter even though no goroutines are running anymore
 	} else {
@@ -190,7 +190,7 @@ func fetchDraftRelease(ctx context.Context, httpClient *http.Client, repo ghrepo
 	}
 
 	if query.Repository.Release == nil || !query.Repository.Release.IsDraft {
-		return nil, errNotFound
+		return nil, ErrReleaseNotFound
 	}
 
 	// Then, use REST to get information about the draft release. In theory, we could have fetched
@@ -213,7 +213,7 @@ func fetchReleasePath(ctx context.Context, httpClient *http.Client, host string,
 
 	if resp.StatusCode == 404 {
 		_, _ = io.Copy(io.Discard, resp.Body)
-		return nil, errNotFound
+		return nil, ErrReleaseNotFound
 	} else if resp.StatusCode > 299 {
 		return nil, api.HandleHTTPError(resp)
 	}