Allow force push to protected branches (#28086)

Fixes #22722 

### Problem
Currently, it is not possible to force push to a branch with branch
protection rules in place. There are often times where this is necessary
(CI workflows/administrative tasks etc).

The current workaround is to rename/remove the branch protection,
perform the force push, and then reinstate the protections.

### Solution
Provide an additional section in the branch protection rules to allow
users to specify which users with push access can also force push to the
branch. The default value of the rule will be set to `Disabled`, and the
UI is intuitive and very similar to the `Push` section.

It is worth noting in this implementation that allowing force push does
not override regular push access, and both will need to be enabled for a
user to force push.

This applies to manual force push to a remote, and also in Gitea UI
updating a PR by rebase (which requires force push)

This modifies the `BranchProtection` API structs to add:
- `enable_force_push bool`
- `enable_force_push_whitelist bool`
- `force_push_whitelist_usernames string[]`
- `force_push_whitelist_teams string[]`
- `force_push_whitelist_deploy_keys bool`

### Updated Branch Protection UI:

<img width="943" alt="image"
src="https://github.com/go-gitea/gitea/assets/79623665/7491899c-d816-45d5-be84-8512abd156bf">

### Pull Request `Update branch by Rebase` option enabled with source
branch `test` being a protected branch:


![image](https://github.com/go-gitea/gitea/assets/79623665/e018e6e9-b7b2-4bd3-808e-4947d7da35cc)
<img width="1038" alt="image"
src="https://github.com/go-gitea/gitea/assets/79623665/57ead13e-9006-459f-b83c-7079e6f4c654">

---------

Co-authored-by: wxiaoguang <[email protected]>

Author: henrygoodman

Diff for: models/git/protected_branch.go

@@ -44,6 +44,11 @@ type ProtectedBranch struct {
 	WhitelistDeployKeys           bool     `xorm:"NOT NULL DEFAULT false"`
 	MergeWhitelistUserIDs         []int64  `xorm:"JSON TEXT"`
 	MergeWhitelistTeamIDs         []int64  `xorm:"JSON TEXT"`
+	CanForcePush                  bool     `xorm:"NOT NULL DEFAULT false"`
+	EnableForcePushAllowlist      bool     `xorm:"NOT NULL DEFAULT false"`
+	ForcePushAllowlistUserIDs     []int64  `xorm:"JSON TEXT"`
+	ForcePushAllowlistTeamIDs     []int64  `xorm:"JSON TEXT"`
+	ForcePushAllowlistDeployKeys  bool     `xorm:"NOT NULL DEFAULT false"`
 	EnableStatusCheck             bool     `xorm:"NOT NULL DEFAULT false"`
 	StatusCheckContexts           []string `xorm:"JSON TEXT"`
 	EnableApprovalsWhitelist      bool     `xorm:"NOT NULL DEFAULT false"`
@@ -143,6 +148,33 @@ func (protectBranch *ProtectedBranch) CanUserPush(ctx context.Context, user *use
 	return in
 }
 
+// CanUserForcePush returns if some user could force push to this protected branch
+// Since force-push extends normal push, we also check if user has regular push access
+func (protectBranch *ProtectedBranch) CanUserForcePush(ctx context.Context, user *user_model.User) bool {
+	if !protectBranch.CanForcePush {
+		return false
+	}
+
+	if !protectBranch.EnableForcePushAllowlist {
+		return protectBranch.CanUserPush(ctx, user)
+	}
+
+	if slices.Contains(protectBranch.ForcePushAllowlistUserIDs, user.ID) {
+		return protectBranch.CanUserPush(ctx, user)
+	}
+
+	if len(protectBranch.ForcePushAllowlistTeamIDs) == 0 {
+		return false
+	}
+
+	in, err := organization.IsUserInTeams(ctx, user.ID, protectBranch.ForcePushAllowlistTeamIDs)
+	if err != nil {
+		log.Error("IsUserInTeams: %v", err)
+		return false
+	}
+	return in && protectBranch.CanUserPush(ctx, user)
+}
+
 // IsUserMergeWhitelisted checks if some user is whitelisted to merge to this branch
 func IsUserMergeWhitelisted(ctx context.Context, protectBranch *ProtectedBranch, userID int64, permissionInRepo access_model.Permission) bool {
 	if !protectBranch.EnableMergeWhitelist {
@@ -301,6 +333,9 @@ type WhitelistOptions struct {
 	UserIDs []int64
 	TeamIDs []int64
 
+	ForcePushUserIDs []int64
+	ForcePushTeamIDs []int64
+
 	MergeUserIDs []int64
 	MergeTeamIDs []int64
 
@@ -328,6 +363,12 @@ func UpdateProtectBranch(ctx context.Context, repo *repo_model.Repository, prote
 	}
 	protectBranch.WhitelistUserIDs = whitelist
 
+	whitelist, err = updateUserWhitelist(ctx, repo, protectBranch.ForcePushAllowlistUserIDs, opts.ForcePushUserIDs)
+	if err != nil {
+		return err
+	}
+	protectBranch.ForcePushAllowlistUserIDs = whitelist
+
 	whitelist, err = updateUserWhitelist(ctx, repo, protectBranch.MergeWhitelistUserIDs, opts.MergeUserIDs)
 	if err != nil {
 		return err
@@ -347,6 +388,12 @@ func UpdateProtectBranch(ctx context.Context, repo *repo_model.Repository, prote
 	}
 	protectBranch.WhitelistTeamIDs = whitelist
 
+	whitelist, err = updateTeamWhitelist(ctx, repo, protectBranch.ForcePushAllowlistTeamIDs, opts.ForcePushTeamIDs)
+	if err != nil {
+		return err
+	}
+	protectBranch.ForcePushAllowlistTeamIDs = whitelist
+
 	whitelist, err = updateTeamWhitelist(ctx, repo, protectBranch.MergeWhitelistTeamIDs, opts.MergeTeamIDs)
 	if err != nil {
 		return err
@@ -468,43 +515,58 @@ func DeleteProtectedBranch(ctx context.Context, repo *repo_model.Repository, id
 	return nil
 }
 
-// RemoveUserIDFromProtectedBranch remove all user ids from protected branch options
-func RemoveUserIDFromProtectedBranch(ctx context.Context, p *ProtectedBranch, userID int64) error {
-	lenIDs, lenApprovalIDs, lenMergeIDs := len(p.WhitelistUserIDs), len(p.ApprovalsWhitelistUserIDs), len(p.MergeWhitelistUserIDs)
-	p.WhitelistUserIDs = util.SliceRemoveAll(p.WhitelistUserIDs, userID)
-	p.ApprovalsWhitelistUserIDs = util.SliceRemoveAll(p.ApprovalsWhitelistUserIDs, userID)
-	p.MergeWhitelistUserIDs = util.SliceRemoveAll(p.MergeWhitelistUserIDs, userID)
-
-	if lenIDs != len(p.WhitelistUserIDs) || lenApprovalIDs != len(p.ApprovalsWhitelistUserIDs) ||
-		lenMergeIDs != len(p.MergeWhitelistUserIDs) {
-		if _, err := db.GetEngine(ctx).ID(p.ID).Cols(
-			"whitelist_user_i_ds",
-			"merge_whitelist_user_i_ds",
-			"approvals_whitelist_user_i_ds",
-		).Update(p); err != nil {
+// removeIDsFromProtectedBranch is a helper function to remove IDs from protected branch options
+func removeIDsFromProtectedBranch(ctx context.Context, p *ProtectedBranch, userID, teamID int64, columnNames []string) error {
+	lenUserIDs, lenForcePushIDs, lenApprovalIDs, lenMergeIDs := len(p.WhitelistUserIDs), len(p.ForcePushAllowlistUserIDs), len(p.ApprovalsWhitelistUserIDs), len(p.MergeWhitelistUserIDs)
+	lenTeamIDs, lenForcePushTeamIDs, lenApprovalTeamIDs, lenMergeTeamIDs := len(p.WhitelistTeamIDs), len(p.ForcePushAllowlistTeamIDs), len(p.ApprovalsWhitelistTeamIDs), len(p.MergeWhitelistTeamIDs)
+
+	if userID > 0 {
+		p.WhitelistUserIDs = util.SliceRemoveAll(p.WhitelistUserIDs, userID)
+		p.ForcePushAllowlistUserIDs = util.SliceRemoveAll(p.ForcePushAllowlistUserIDs, userID)
+		p.ApprovalsWhitelistUserIDs = util.SliceRemoveAll(p.ApprovalsWhitelistUserIDs, userID)
+		p.MergeWhitelistUserIDs = util.SliceRemoveAll(p.MergeWhitelistUserIDs, userID)
+	}
+
+	if teamID > 0 {
+		p.WhitelistTeamIDs = util.SliceRemoveAll(p.WhitelistTeamIDs, teamID)
+		p.ForcePushAllowlistTeamIDs = util.SliceRemoveAll(p.ForcePushAllowlistTeamIDs, teamID)
+		p.ApprovalsWhitelistTeamIDs = util.SliceRemoveAll(p.ApprovalsWhitelistTeamIDs, teamID)
+		p.MergeWhitelistTeamIDs = util.SliceRemoveAll(p.MergeWhitelistTeamIDs, teamID)
+	}
+
+	if (lenUserIDs != len(p.WhitelistUserIDs) ||
+		lenForcePushIDs != len(p.ForcePushAllowlistUserIDs) ||
+		lenApprovalIDs != len(p.ApprovalsWhitelistUserIDs) ||
+		lenMergeIDs != len(p.MergeWhitelistUserIDs)) ||
+		(lenTeamIDs != len(p.WhitelistTeamIDs) ||
+			lenForcePushTeamIDs != len(p.ForcePushAllowlistTeamIDs) ||
+			lenApprovalTeamIDs != len(p.ApprovalsWhitelistTeamIDs) ||
+			lenMergeTeamIDs != len(p.MergeWhitelistTeamIDs)) {
+		if _, err := db.GetEngine(ctx).ID(p.ID).Cols(columnNames...).Update(p); err != nil {
 			return fmt.Errorf("updateProtectedBranches: %v", err)
 		}
 	}
 	return nil
 }
 
-// RemoveTeamIDFromProtectedBranch remove all team ids from protected branch options
+// RemoveUserIDFromProtectedBranch removes all user ids from protected branch options
+func RemoveUserIDFromProtectedBranch(ctx context.Context, p *ProtectedBranch, userID int64) error {
+	columnNames := []string{
+		"whitelist_user_i_ds",
+		"force_push_allowlist_user_i_ds",
+		"merge_whitelist_user_i_ds",
+		"approvals_whitelist_user_i_ds",
+	}
+	return removeIDsFromProtectedBranch(ctx, p, userID, 0, columnNames)
+}
+
+// RemoveTeamIDFromProtectedBranch removes all team ids from protected branch options
 func RemoveTeamIDFromProtectedBranch(ctx context.Context, p *ProtectedBranch, teamID int64) error {
-	lenIDs, lenApprovalIDs, lenMergeIDs := len(p.WhitelistTeamIDs), len(p.ApprovalsWhitelistTeamIDs), len(p.MergeWhitelistTeamIDs)
-	p.WhitelistTeamIDs = util.SliceRemoveAll(p.WhitelistTeamIDs, teamID)
-	p.ApprovalsWhitelistTeamIDs = util.SliceRemoveAll(p.ApprovalsWhitelistTeamIDs, teamID)
-	p.MergeWhitelistTeamIDs = util.SliceRemoveAll(p.MergeWhitelistTeamIDs, teamID)
-
-	if lenIDs != len(p.WhitelistTeamIDs) ||
-		lenApprovalIDs != len(p.ApprovalsWhitelistTeamIDs) ||
-		lenMergeIDs != len(p.MergeWhitelistTeamIDs) {
-		if _, err := db.GetEngine(ctx).ID(p.ID).Cols(
-			"whitelist_team_i_ds",
-			"merge_whitelist_team_i_ds",
-			"approvals_whitelist_team_i_ds",
-		).Update(p); err != nil {
-			return fmt.Errorf("updateProtectedBranches: %v", err)
-		}
+	columnNames := []string{
+		"whitelist_team_i_ds",
+		"force_push_allowlist_team_i_ds",
+		"merge_whitelist_team_i_ds",
+		"approvals_whitelist_team_i_ds",
 	}
-	return nil
+	return removeIDsFromProtectedBranch(ctx, p, 0, teamID, columnNames)
 }

Diff for: models/migrations/migrations.go

@@ -591,6 +591,8 @@ var migrations = []Migration{
 
 	// v299 -> v300
 	NewMigration("Add content version to issue and comment table", v1_23.AddContentVersionToIssueAndComment),
+	// v300 -> v301
+	NewMigration("Add force-push branch protection support", v1_23.AddForcePushBranchProtection),
 }
 
 // GetCurrentDBVersion returns the current db version

Diff for: models/migrations/v1_23/v300.go

@@ -0,0 +1,17 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_23 //nolint
+
+import "xorm.io/xorm"
+
+func AddForcePushBranchProtection(x *xorm.Engine) error {
+	type ProtectedBranch struct {
+		CanForcePush                 bool    `xorm:"NOT NULL DEFAULT false"`
+		EnableForcePushAllowlist     bool    `xorm:"NOT NULL DEFAULT false"`
+		ForcePushAllowlistUserIDs    []int64 `xorm:"JSON TEXT"`
+		ForcePushAllowlistTeamIDs    []int64 `xorm:"JSON TEXT"`
+		ForcePushAllowlistDeployKeys bool    `xorm:"NOT NULL DEFAULT false"`
+	}
+	return x.Sync(new(ProtectedBranch))
+}

Diff for: modules/structs/repo_branch.go

@@ -30,6 +30,11 @@ type BranchProtection struct {
 	PushWhitelistUsernames        []string `json:"push_whitelist_usernames"`
 	PushWhitelistTeams            []string `json:"push_whitelist_teams"`
 	PushWhitelistDeployKeys       bool     `json:"push_whitelist_deploy_keys"`
+	EnableForcePush               bool     `json:"enable_force_push"`
+	EnableForcePushAllowlist      bool     `json:"enable_force_push_allowlist"`
+	ForcePushAllowlistUsernames   []string `json:"force_push_allowlist_usernames"`
+	ForcePushAllowlistTeams       []string `json:"force_push_allowlist_teams"`
+	ForcePushAllowlistDeployKeys  bool     `json:"force_push_allowlist_deploy_keys"`
 	EnableMergeWhitelist          bool     `json:"enable_merge_whitelist"`
 	MergeWhitelistUsernames       []string `json:"merge_whitelist_usernames"`
 	MergeWhitelistTeams           []string `json:"merge_whitelist_teams"`
@@ -63,6 +68,11 @@ type CreateBranchProtectionOption struct {
 	PushWhitelistUsernames        []string `json:"push_whitelist_usernames"`
 	PushWhitelistTeams            []string `json:"push_whitelist_teams"`
 	PushWhitelistDeployKeys       bool     `json:"push_whitelist_deploy_keys"`
+	EnableForcePush               bool     `json:"enable_force_push"`
+	EnableForcePushAllowlist      bool     `json:"enable_force_push_allowlist"`
+	ForcePushAllowlistUsernames   []string `json:"force_push_allowlist_usernames"`
+	ForcePushAllowlistTeams       []string `json:"force_push_allowlist_teams"`
+	ForcePushAllowlistDeployKeys  bool     `json:"force_push_allowlist_deploy_keys"`
 	EnableMergeWhitelist          bool     `json:"enable_merge_whitelist"`
 	MergeWhitelistUsernames       []string `json:"merge_whitelist_usernames"`
 	MergeWhitelistTeams           []string `json:"merge_whitelist_teams"`
@@ -89,6 +99,11 @@ type EditBranchProtectionOption struct {
 	PushWhitelistUsernames        []string `json:"push_whitelist_usernames"`
 	PushWhitelistTeams            []string `json:"push_whitelist_teams"`
 	PushWhitelistDeployKeys       *bool    `json:"push_whitelist_deploy_keys"`
+	EnableForcePush               *bool    `json:"enable_force_push"`
+	EnableForcePushAllowlist      *bool    `json:"enable_force_push_allowlist"`
+	ForcePushAllowlistUsernames   []string `json:"force_push_allowlist_usernames"`
+	ForcePushAllowlistTeams       []string `json:"force_push_allowlist_teams"`
+	ForcePushAllowlistDeployKeys  *bool    `json:"force_push_allowlist_deploy_keys"`
 	EnableMergeWhitelist          *bool    `json:"enable_merge_whitelist"`
 	MergeWhitelistUsernames       []string `json:"merge_whitelist_usernames"`
 	MergeWhitelistTeams           []string `json:"merge_whitelist_teams"`

Diff for: options/locale/locale_en-US.ini

@@ -2280,6 +2280,7 @@ settings.event_wiki_desc = Wiki page created, renamed, edited or deleted.
 settings.event_release = Release
 settings.event_release_desc = Release published, updated or deleted in a repository.
 settings.event_push = Push
+settings.event_force_push = Force Push
 settings.event_push_desc = Git push to a repository.
 settings.event_repository = Repository
 settings.event_repository_desc = Repository created or deleted.
@@ -2373,19 +2374,28 @@ settings.protect_this_branch = Enable Branch Protection
 settings.protect_this_branch_desc = Prevents deletion and restricts Git pushing and merging to the branch.
 settings.protect_disable_push = Disable Push
 settings.protect_disable_push_desc = No pushing will be allowed to this branch.
+settings.protect_disable_force_push = Disable Force Push
+settings.protect_disable_force_push_desc = No force pushing will be allowed to this branch.
 settings.protect_enable_push = Enable Push
 settings.protect_enable_push_desc = Anyone with write access will be allowed to push to this branch (but not force push).
+settings.protect_enable_force_push_all = Enable Force Push
+settings.protect_enable_force_push_all_desc = Anyone with push access will be allowed to force push to this branch.
+settings.protect_enable_force_push_allowlist = Allowlist Restricted Force Push
+settings.protect_enable_force_push_allowlist_desc = Only allowlisted users or teams with push access will be allowed to force push to this branch.
 settings.protect_enable_merge = Enable Merge
 settings.protect_enable_merge_desc = Anyone with write access will be allowed to merge the pull requests into this branch.
-settings.protect_whitelist_committers = Whitelist Restricted Push
-settings.protect_whitelist_committers_desc = Only whitelisted users or teams will be allowed to push to this branch (but not force push).
-settings.protect_whitelist_deploy_keys = Whitelist deploy keys with write access to push.
-settings.protect_whitelist_users = Whitelisted users for pushing:
-settings.protect_whitelist_teams = Whitelisted teams for pushing:
-settings.protect_merge_whitelist_committers = Enable Merge Whitelist
-settings.protect_merge_whitelist_committers_desc = Allow only whitelisted users or teams to merge pull requests into this branch.
-settings.protect_merge_whitelist_users = Whitelisted users for merging:
-settings.protect_merge_whitelist_teams = Whitelisted teams for merging:
+settings.protect_whitelist_committers = Allowlist Restricted Push
+settings.protect_whitelist_committers_desc = Only allowlisted users or teams will be allowed to push to this branch (but not force push).
+settings.protect_whitelist_deploy_keys = Allowlist deploy keys with write access to push.
+settings.protect_whitelist_users = Allowlisted users for pushing:
+settings.protect_whitelist_teams = Allowlisted teams for pushing:
+settings.protect_force_push_allowlist_users = Allowlisted users for force pushing:
+settings.protect_force_push_allowlist_teams = Allowlisted teams for force pushing:
+settings.protect_force_push_allowlist_deploy_keys = Allowlist deploy keys with push access to force push.
+settings.protect_merge_whitelist_committers = Enable Merge Allowlist
+settings.protect_merge_whitelist_committers_desc = Allow only allowlisted users or teams to merge pull requests into this branch.
+settings.protect_merge_whitelist_users = Allowlisted users for merging:
+settings.protect_merge_whitelist_teams = Allowlisted teams for merging:
 settings.protect_check_status_contexts = Enable Status Check
 settings.protect_status_check_patterns = Status check patterns:
 settings.protect_status_check_patterns_desc = Enter patterns to specify which status checks must pass before branches can be merged into a branch that matches this rule. Each line specifies a pattern. Patterns cannot be empty.
@@ -2396,10 +2406,10 @@ settings.protect_invalid_status_check_pattern = Invalid status check pattern: "%
 settings.protect_no_valid_status_check_patterns = No valid status check patterns.
 settings.protect_required_approvals = Required approvals:
 settings.protect_required_approvals_desc = Allow only to merge pull request with enough positive reviews.
-settings.protect_approvals_whitelist_enabled = Restrict approvals to whitelisted users or teams
-settings.protect_approvals_whitelist_enabled_desc = Only reviews from whitelisted users or teams will count to the required approvals. Without approval whitelist, reviews from anyone with write access count to the required approvals.
-settings.protect_approvals_whitelist_users = Whitelisted reviewers:
-settings.protect_approvals_whitelist_teams = Whitelisted teams for reviews:
+settings.protect_approvals_whitelist_enabled = Restrict approvals to allowlisted users or teams
+settings.protect_approvals_whitelist_enabled_desc = Only reviews from allowlisted users or teams will count to the required approvals. Without approval allowlist, reviews from anyone with write access count to the required approvals.
+settings.protect_approvals_whitelist_users = Allowlisted reviewers:
+settings.protect_approvals_whitelist_teams = Allowlisted teams for reviews:
 settings.dismiss_stale_approvals = Dismiss stale approvals
 settings.dismiss_stale_approvals_desc = When new commits that change the content of the pull request are pushed to the branch, old approvals will be dismissed.
 settings.ignore_stale_approvals = Ignore stale approvals