Add a fast-forward-only merge style. (#24906)

chrisnc · chrisnc · commit 7ede430c28ca · 2024-01-27T01:57:43.000-08:00
diff --git a/models/repo/git.go b/models/repo/git.go
@@ -21,6 +21,8 @@ const (
 	MergeStyleRebaseMerge MergeStyle = "rebase-merge"
 	// MergeStyleSquash squash commits into single commit before merging
 	MergeStyleSquash MergeStyle = "squash"
+	// MergeStyleFastForwardOnly fast-forward merge if possible, otherwise fail
+	MergeStyleFastForwardOnly MergeStyle = "fast-forward-only"
 	// MergeStyleManuallyMerged pr has been merged manually, just mark it as merged directly
 	MergeStyleManuallyMerged MergeStyle = "manually-merged"
 	// MergeStyleRebaseUpdate not a merge style, used to update pull head by rebase
diff --git a/models/repo/repo_unit.go b/models/repo/repo_unit.go
@@ -122,6 +122,7 @@ type PullRequestsConfig struct {
 	AllowRebase                   bool
 	AllowRebaseMerge              bool
 	AllowSquash                   bool
+	AllowFastForwardOnly          bool
 	AllowManualMerge              bool
 	AutodetectManualMerge         bool
 	AllowRebaseUpdate             bool
@@ -148,6 +149,7 @@ func (cfg *PullRequestsConfig) IsMergeStyleAllowed(mergeStyle MergeStyle) bool {
 		mergeStyle == MergeStyleRebase && cfg.AllowRebase ||
 		mergeStyle == MergeStyleRebaseMerge && cfg.AllowRebaseMerge ||
 		mergeStyle == MergeStyleSquash && cfg.AllowSquash ||
+		mergeStyle == MergeStyleFastForwardOnly && cfg.AllowFastForwardOnly ||
 		mergeStyle == MergeStyleManuallyMerged && cfg.AllowManualMerge
 }
 
diff --git a/modules/git/error.go b/modules/git/error.go
@@ -96,7 +96,7 @@ func (err ErrBranchNotExist) Unwrap() error {
 	return util.ErrNotExist
 }
 
-// ErrPushOutOfDate represents an error if merging fails due to unrelated histories
+// ErrPushOutOfDate represents an error if merging fails due to the base branch being updated
 type ErrPushOutOfDate struct {
 	StdOut string
 	StdErr string
diff --git a/modules/repository/create.go b/modules/repository/create.go
@@ -87,7 +87,11 @@ func CreateRepositoryByExample(ctx context.Context, doer, u *user_model.User, re
 			units = append(units, repo_model.RepoUnit{
 				RepoID: repo.ID,
 				Type:   tp,
-				Config: &repo_model.PullRequestsConfig{AllowMerge: true, AllowRebase: true, AllowRebaseMerge: true, AllowSquash: true, DefaultMergeStyle: repo_model.MergeStyle(setting.Repository.PullRequest.DefaultMergeStyle), AllowRebaseUpdate: true},
+				Config: &repo_model.PullRequestsConfig{
+					AllowMerge: true, AllowRebase: true, AllowRebaseMerge: true, AllowSquash: true, AllowFastForwardOnly: true,
+					DefaultMergeStyle: repo_model.MergeStyle(setting.Repository.PullRequest.DefaultMergeStyle),
+					AllowRebaseUpdate: true,
+				},
 			})
 		} else {
 			units = append(units, repo_model.RepoUnit{
diff --git a/modules/structs/repo.go b/modules/structs/repo.go
@@ -98,6 +98,7 @@ type Repository struct {
 	AllowRebase                   bool             `json:"allow_rebase"`
 	AllowRebaseMerge              bool             `json:"allow_rebase_explicit"`
 	AllowSquash                   bool             `json:"allow_squash_merge"`
+	AllowFastForwardOnly          bool             `json:"allow_fast_forward_only_merge"`
 	AllowRebaseUpdate             bool             `json:"allow_rebase_update"`
 	DefaultDeleteBranchAfterMerge bool             `json:"default_delete_branch_after_merge"`
 	DefaultMergeStyle             string           `json:"default_merge_style"`
@@ -195,6 +196,8 @@ type EditRepoOption struct {
 	AllowRebaseMerge *bool `json:"allow_rebase_explicit,omitempty"`
 	// either `true` to allow squash-merging pull requests, or `false` to prevent squash-merging.
 	AllowSquash *bool `json:"allow_squash_merge,omitempty"`
+	// either `true` to allow fast-forward-only merging pull requests, or `false` to prevent fast-forward-only merging.
+	AllowFastForwardOnly *bool `json:"allow_fast_forward_only_merge,omitempty"`
 	// either `true` to allow mark pr as merged manually, or `false` to prevent it.
 	AllowManualMerge *bool `json:"allow_manual_merge,omitempty"`
 	// either `true` to enable AutodetectManualMerge, or `false` to prevent it. Note: In some special cases, misjudgments can occur.
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
@@ -1775,6 +1775,7 @@ pulls.merge_pull_request = Create merge commit
 pulls.rebase_merge_pull_request = Rebase then fast-forward
 pulls.rebase_merge_commit_pull_request = Rebase then create merge commit
 pulls.squash_merge_pull_request = Create squash commit
+pulls.fast_forward_only_merge_pull_request = Fast-forward
 pulls.merge_manually = Manually merged
 pulls.merge_commit_id = The merge commit ID
 pulls.require_signed_wont_sign = The branch requires signed commits but this merge will not be signed
diff --git a/routers/api/v1/repo/repo.go b/routers/api/v1/repo/repo.go
@@ -883,6 +883,7 @@ func updateRepoUnits(ctx *context.APIContext, opts api.EditRepoOption) error {
 					AllowRebase:                   true,
 					AllowRebaseMerge:              true,
 					AllowSquash:                   true,
+					AllowFastForwardOnly:          true,
 					AllowManualMerge:              true,
 					AutodetectManualMerge:         false,
 					AllowRebaseUpdate:             true,
@@ -909,6 +910,9 @@ func updateRepoUnits(ctx *context.APIContext, opts api.EditRepoOption) error {
 			if opts.AllowSquash != nil {
 				config.AllowSquash = *opts.AllowSquash
 			}
+			if opts.AllowFastForwardOnly != nil {
+				config.AllowFastForwardOnly = *opts.AllowFastForwardOnly
+			}
 			if opts.AllowManualMerge != nil {
 				config.AllowManualMerge = *opts.AllowManualMerge
 			}
diff --git a/routers/api/v1/repo/repo_test.go b/routers/api/v1/repo/repo_test.go
@@ -35,6 +35,7 @@ func TestRepoEdit(t *testing.T) {
 	allowRebase := false
 	allowRebaseMerge := false
 	allowSquashMerge := false
+	allowFastForwardOnlyMerge := false
 	archived := true
 	opts := api.EditRepoOption{
 		Name:                      &ctx.Repo.Repository.Name,
@@ -50,6 +51,7 @@ func TestRepoEdit(t *testing.T) {
 		AllowRebase:               &allowRebase,
 		AllowRebaseMerge:          &allowRebaseMerge,
 		AllowSquash:               &allowSquashMerge,
+		AllowFastForwardOnly:      &allowFastForwardOnlyMerge,
 		Archived:                  &archived,
 	}
 
diff --git a/routers/web/repo/issue.go b/routers/web/repo/issue.go
@@ -1862,6 +1862,8 @@ func ViewIssue(ctx *context.Context) {
 				mergeStyle = repo_model.MergeStyleRebaseMerge
 			} else if prConfig.AllowSquash {
 				mergeStyle = repo_model.MergeStyleSquash
+			} else if prConfig.AllowFastForwardOnly {
+				mergeStyle = repo_model.MergeStyleFastForwardOnly
 			} else if prConfig.AllowManualMerge {
 				mergeStyle = repo_model.MergeStyleManuallyMerged
 			}
diff --git a/routers/web/repo/setting/setting.go b/routers/web/repo/setting/setting.go
@@ -576,6 +576,7 @@ func SettingsPost(ctx *context.Context) {
 					AllowRebase:                   form.PullsAllowRebase,
 					AllowRebaseMerge:              form.PullsAllowRebaseMerge,
 					AllowSquash:                   form.PullsAllowSquash,
+					AllowFastForwardOnly:          form.PullsAllowFastForwardOnly,
 					AllowManualMerge:              form.PullsAllowManualMerge,
 					AutodetectManualMerge:         form.EnableAutodetectManualMerge,
 					AllowRebaseUpdate:             form.PullsAllowRebaseUpdate,
diff --git a/services/convert/repository.go b/services/convert/repository.go
@@ -93,6 +93,7 @@ func innerToRepo(ctx context.Context, repo *repo_model.Repository, permissionInR
 	allowRebase := false
 	allowRebaseMerge := false
 	allowSquash := false
+	allowFastForwardOnly := false
 	allowRebaseUpdate := false
 	defaultDeleteBranchAfterMerge := false
 	defaultMergeStyle := repo_model.MergeStyleMerge
@@ -105,6 +106,7 @@ func innerToRepo(ctx context.Context, repo *repo_model.Repository, permissionInR
 		allowRebase = config.AllowRebase
 		allowRebaseMerge = config.AllowRebaseMerge
 		allowSquash = config.AllowSquash
+		allowFastForwardOnly = config.AllowFastForwardOnly
 		allowRebaseUpdate = config.AllowRebaseUpdate
 		defaultDeleteBranchAfterMerge = config.DefaultDeleteBranchAfterMerge
 		defaultMergeStyle = config.GetDefaultMergeStyle()
@@ -219,6 +221,7 @@ func innerToRepo(ctx context.Context, repo *repo_model.Repository, permissionInR
 		AllowRebase:                   allowRebase,
 		AllowRebaseMerge:              allowRebaseMerge,
 		AllowSquash:                   allowSquash,
+		AllowFastForwardOnly:          allowFastForwardOnly,
 		AllowRebaseUpdate:             allowRebaseUpdate,
 		DefaultDeleteBranchAfterMerge: defaultDeleteBranchAfterMerge,
 		DefaultMergeStyle:             string(defaultMergeStyle),
diff --git a/services/forms/repo_form.go b/services/forms/repo_form.go
@@ -151,6 +151,7 @@ type RepoSettingForm struct {
 	PullsAllowRebase                      bool
 	PullsAllowRebaseMerge                 bool
 	PullsAllowSquash                      bool
+	PullsAllowFastForwardOnly             bool
 	PullsAllowManualMerge                 bool
 	PullsDefaultMergeStyle                string
 	EnableAutodetectManualMerge           bool
diff --git a/services/pull/merge.go b/services/pull/merge.go
@@ -267,6 +267,10 @@ func doMergeAndPush(ctx context.Context, pr *issues_model.PullRequest, doer *use
 		if err := doMergeStyleSquash(mergeCtx, message); err != nil {
 			return "", err
 		}
+	case repo_model.MergeStyleFastForwardOnly:
+		if err := doMergeStyleFastForwardOnly(mergeCtx); err != nil {
+			return "", err
+		}
 	default:
 		return "", models.ErrInvalidMergeStyle{ID: pr.BaseRepo.ID, Style: mergeStyle}
 	}
diff --git a/services/pull/merge_ff_only.go b/services/pull/merge_ff_only.go
@@ -0,0 +1,21 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package pull
+
+import (
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+)
+
+// doMergeStyleFastForwardOnly merges the tracking into the current HEAD - which is assumed to be staging branch (equal to the pr.BaseBranch)
+func doMergeStyleFastForwardOnly(ctx *mergeContext) error {
+	cmd := git.NewCommand(ctx, "merge", "--ff-only").AddDynamicArguments(trackingBranch)
+	if err := runMergeCommand(ctx, repo_model.MergeStyleFastForwardOnly, cmd); err != nil {
+		log.Error("%-v Unable to merge tracking into base: %v", ctx.pr, err)
+		return err
+	}
+
+	return nil
+}
diff --git a/services/pull/merge_merge.go b/services/pull/merge_merge.go
@@ -9,7 +9,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 )
 
-// doMergeStyleMerge merges the tracking into the current HEAD - which is assumed to tbe staging branch (equal to the pr.BaseBranch)
+// doMergeStyleMerge merges the tracking branch into the current HEAD - which is assumed to be the staging branch (equal to the pr.BaseBranch)
 func doMergeStyleMerge(ctx *mergeContext, message string) error {
 	cmd := git.NewCommand(ctx, "merge", "--no-ff", "--no-commit").AddDynamicArguments(trackingBranch)
 	if err := runMergeCommand(ctx, repo_model.MergeStyleMerge, cmd); err != nil {
diff --git a/templates/repo/issue/view_content/pull.tmpl b/templates/repo/issue/view_content/pull.tmpl
@@ -197,7 +197,7 @@
 				{{if .AllowMerge}} {{/* user is allowed to merge */}}
 					{{$prUnit := .Repository.MustGetUnit $.Context $.UnitTypePullRequests}}
 					{{$approvers := (.Issue.PullRequest.GetApprovers ctx)}}
-					{{if or $prUnit.PullRequestsConfig.AllowMerge $prUnit.PullRequestsConfig.AllowRebase $prUnit.PullRequestsConfig.AllowRebaseMerge $prUnit.PullRequestsConfig.AllowSquash}}
+					{{if or $prUnit.PullRequestsConfig.AllowMerge $prUnit.PullRequestsConfig.AllowRebase $prUnit.PullRequestsConfig.AllowRebaseMerge $prUnit.PullRequestsConfig.AllowSquash $prUnit.PullRequestsConfig.AllowFastForwardOnly}}
 						{{$hasPendingPullRequestMergeTip := ""}}
 						{{if .HasPendingPullRequestMerge}}
 							{{$createdPRMergeStr := TimeSinceUnix .PendingPullRequestMerge.CreatedUnix ctx.Locale}}
@@ -268,6 +268,13 @@
 									'mergeMessageFieldText': {{.GetCommitMessages}} + defaultSquashMergeMessage,
 									'hideAutoMerge': generalHideAutoMerge,
 								},
+								{
+									'name': 'fast-forward-only',
+									'allowed': {{and $prUnit.PullRequestsConfig.AllowFastForwardOnly (eq .Issue.PullRequest.CommitsBehind 0)}},
+									'textDoMerge': {{$.locale.Tr "repo.pulls.fast_forward_only_merge_pull_request"}},
+									'hideMergeMessageTexts': true,
+									'hideAutoMerge': generalHideAutoMerge,
+								},
 								{
 									'name': 'manually-merged',
 									'allowed': {{$prUnit.PullRequestsConfig.AllowManualMerge}},
diff --git a/templates/repo/settings/options.tmpl b/templates/repo/settings/options.tmpl
@@ -517,6 +517,12 @@
 								<label>{{ctx.Locale.Tr "repo.pulls.squash_merge_pull_request"}}</label>
 							</div>
 						</div>
+						<div class="field">
+							<div class="ui checkbox">
+								<input name="pulls_allow_fast_forward_only" type="checkbox" {{if or (not $pullRequestEnabled) ($prUnit.PullRequestsConfig.AllowFastForwardOnly)}}checked{{end}}>
+								<label>{{.locale.Tr "repo.pulls.fast_forward_only_merge_pull_request"}}</label>
+							</div>
+						</div>
 						<div class="field">
 							<div class="ui checkbox">
 								<input name="pulls_allow_manual_merge" type="checkbox" {{if or (not $pullRequestEnabled) ($prUnit.PullRequestsConfig.AllowManualMerge)}}checked{{end}}>
@@ -534,6 +540,7 @@
 									<option value="rebase" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "rebase")}}selected{{end}}>{{ctx.Locale.Tr "repo.pulls.rebase_merge_pull_request"}}</option>
 									<option value="rebase-merge" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "rebase-merge")}}selected{{end}}>{{ctx.Locale.Tr "repo.pulls.rebase_merge_commit_pull_request"}}</option>
 									<option value="squash" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "squash")}}selected{{end}}>{{ctx.Locale.Tr "repo.pulls.squash_merge_pull_request"}}</option>
+									<option value="fast-forward-only" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "fast-forward-only")}}selected{{end}}>{{ctx.Locale.Tr "repo.pulls.fast_forward_only_merge_pull_request"}}</option>
 								</select>{{svg "octicon-triangle-down" 14 "dropdown icon"}}
 								<div class="default text">
 									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "merge")}}
@@ -548,12 +555,16 @@
 									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "squash")}}
 										{{ctx.Locale.Tr "repo.pulls.squash_merge_pull_request"}}
 									{{end}}
+									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "fast-forward-only")}}
+										{{.locale.Tr "repo.pulls.fast_forward_only_merge_pull_request"}}
+									{{end}}
 								</div>
 								<div class="menu">
 									<div class="item" data-value="merge">{{ctx.Locale.Tr "repo.pulls.merge_pull_request"}}</div>
 									<div class="item" data-value="rebase">{{ctx.Locale.Tr "repo.pulls.rebase_merge_pull_request"}}</div>
 									<div class="item" data-value="rebase-merge">{{ctx.Locale.Tr "repo.pulls.rebase_merge_commit_pull_request"}}</div>
 									<div class="item" data-value="squash">{{ctx.Locale.Tr "repo.pulls.squash_merge_pull_request"}}</div>
+									<div class="item" data-value="fast-forward-only">{{ctx.Locale.Tr "repo.pulls.fast_forward_only_merge_pull_request"}}</div>
 								</div>
 							</div>
 						</div>
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
diff --git a/tests/integration/api_repo_edit_test.go b/tests/integration/api_repo_edit_test.go
@@ -65,6 +65,7 @@ func getRepoEditOptionFromRepo(repo *repo_model.Repository) *api.EditRepoOption
 	allowRebase := false
 	allowRebaseMerge := false
 	allowSquash := false
+	allowFastForwardOnly := false
 	if unit, err := repo.GetUnit(db.DefaultContext, unit_model.TypePullRequests); err == nil {
 		config := unit.PullRequestsConfig()
 		hasPullRequests = true
@@ -73,6 +74,7 @@ func getRepoEditOptionFromRepo(repo *repo_model.Repository) *api.EditRepoOption
 		allowRebase = config.AllowRebase
 		allowRebaseMerge = config.AllowRebaseMerge
 		allowSquash = config.AllowSquash
+		allowFastForwardOnly = config.AllowFastForwardOnly
 	}
 	archived := repo.IsArchived
 	return &api.EditRepoOption{
@@ -92,6 +94,7 @@ func getRepoEditOptionFromRepo(repo *repo_model.Repository) *api.EditRepoOption
 		AllowRebase:               &allowRebase,
 		AllowRebaseMerge:          &allowRebaseMerge,
 		AllowSquash:               &allowSquash,
+		AllowFastForwardOnly:      &allowFastForwardOnly,
 		Archived:                  &archived,
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -96,7 +96,7 @@ func (err ErrBranchNotExist) Unwrap() error {`
`96`	`96`	`return util.ErrNotExist`
`97`	`97`	`}`
`98`	`98`
`99`		`-// ErrPushOutOfDate represents an error if merging fails due to unrelated histories`
	`99`	`+// ErrPushOutOfDate represents an error if merging fails due to the base branch being updated`
`100`	`100`	`type ErrPushOutOfDate struct {`
`101`	`101`	`StdOut string`
`102`	`102`	`StdErr string`
Original file line number	Diff line number	Diff line change
`@@ -1862,6 +1862,8 @@ func ViewIssue(ctx *context.Context) {`
`1862`	`1862`	`mergeStyle = repo_model.MergeStyleRebaseMerge`
`1863`	`1863`	`} else if prConfig.AllowSquash {`
`1864`	`1864`	`mergeStyle = repo_model.MergeStyleSquash`
	`1865`	`+ } else if prConfig.AllowFastForwardOnly {`
	`1866`	`+ mergeStyle = repo_model.MergeStyleFastForwardOnly`
`1865`	`1867`	`} else if prConfig.AllowManualMerge {`
`1866`	`1868`	`mergeStyle = repo_model.MergeStyleManuallyMerged`
`1867`	`1869`	`}`