Add Pull Request merge options - Ignore white-space for conflict checking, Rebase, Squash merge (#3188)

* Pull request options migration and UI in settings

* Add ignore whitespace functionality

* Fix settings if pull requests are disabled

* Fix migration transaction

* Merge with Rebase functionality

* UI changes and related functionality for pull request merging button

* Implement squash functionality

* Fix rebase merging

* Fix pull request merge tests

* Add squash and rebase tests

* Fix API method to reuse default message functions

* Some refactoring and small fixes

* Remove more hardcoded values from tests

* Remove unneeded check from API method

* Fix variable name and comment typo

* Fix reset commit count after PR merge

2 files changed, 122 insertions, 10 deletions

diff --git a/templates/repo/issue/view_content/pull.tmpl b/templates/repo/issue/view_content/pull.tmpl
index 87de9c508b..9bd51b7c3e 100644
--- a/templates/repo/issue/view_content/pull.tmpl
+++ b/templates/repo/issue/view_content/pull.tmpl
@@ -38,15 +38,100 @@
 					{{$.i18n.Tr "repo.pulls.can_auto_merge_desc"}}
 				</div>
 				{{if .IsRepositoryWriter}}
-					<div class="ui divider"></div>
-					<div>
-						<form class="ui form" action="{{.Link}}/merge" method="post">
-							{{.CsrfTokenHtml}}
-							<button class="ui green button">
-								<span class="octicon octicon-git-merge"></span> {{$.i18n.Tr "repo.pulls.merge_pull_request"}}
+					{{$prUnit := .Repository.MustGetUnit $.UnitTypePullRequests}}
+					{{if or $prUnit.PullRequestsConfig.AllowMerge $prUnit.PullRequestsConfig.AllowRebase $prUnit.PullRequestsConfig.AllowSquash}}
+						<div class="ui divider"></div>
+						{{if $prUnit.PullRequestsConfig.AllowMerge}}
+						<div class="ui form merge-fields" style="display: none">
+							<form action="{{.Link}}/merge" method="post">
+								{{.CsrfTokenHtml}}
+								<div class="field">
+									<input type="text" name="merge_title_field" value="{{.Issue.PullRequest.GetDefaultMergeMessage}}">
+								</div>
+								<div class="field">
+									<textarea name="merge_message_field" rows="5" placeholder="{{$.i18n.Tr "repo.editor.commit_message_desc"}}"></textarea>
+								</div>
+								<button class="ui green button" type="submit" name="do" value="merge">
+									{{$.i18n.Tr "repo.pulls.merge_pull_request"}}
+								</button>
+								<button class="ui button merge-cancel">
+									{{$.i18n.Tr "cancel"}}
+								</button>
+							</form>
+						</div>
+						{{end}}
+						{{if $prUnit.PullRequestsConfig.AllowRebase}}
+						<div class="ui form rebase-fields" style="display: none">
+							<form action="{{.Link}}/merge" method="post">
+								{{.CsrfTokenHtml}}
+								<button class="ui green button" type="submit" name="do" value="rebase">
+									{{$.i18n.Tr "repo.pulls.rebase_merge_pull_request"}}
+								</button>
+								<button class="ui button merge-cancel">
+									{{$.i18n.Tr "cancel"}}
+								</button>
+							</form>
+						</div>
+						{{end}}
+						{{if $prUnit.PullRequestsConfig.AllowSquash}}
+						<div class="ui form squash-fields" style="display: none">
+							<form action="{{.Link}}/merge" method="post">
+								{{.CsrfTokenHtml}}
+								<div class="field">
+									<input type="text" name="merge_title_field" value="{{.Issue.PullRequest.GetDefaultSquashMessage}}">
+								</div>
+								<div class="field">
+									<textarea name="merge_message_field" rows="5" placeholder="{{$.i18n.Tr "repo.editor.commit_message_desc"}}"></textarea>
+								</div>
+								<button class="ui green button" type="submit" name="do" value="squash">
+									{{$.i18n.Tr "repo.pulls.squash_merge_pull_request"}}
+								</button>
+								<button class="ui button merge-cancel">
+									{{$.i18n.Tr "cancel"}}
+								</button>
+							</form>
+						</div>
+						{{end}}
+						<div class="ui green buttons merge-button">
+							<button class="ui button" data-do="{{.MergeStyle}}">
+								<span class="octicon octicon-git-merge"></span>
+								<span class="button-text">
+								{{if eq .MergeStyle "merge"}}
+									{{$.i18n.Tr "repo.pulls.merge_pull_request"}}
+								{{end}}
+								{{if eq .MergeStyle "rebase"}}
+									{{$.i18n.Tr "repo.pulls.rebase_merge_pull_request"}}
+								{{end}}
+								{{if eq .MergeStyle "squash"}}
+									{{$.i18n.Tr "repo.pulls.squash_merge_pull_request"}}
+								{{end}}
+								</span>
 							</button>
-						</form>
-					</div>
+							<div class="ui dropdown icon button">
+								<i class="dropdown icon"></i>
+								<div class="menu">
+									{{if $prUnit.PullRequestsConfig.AllowMerge}}
+									<div class="item{{if eq .MergeStyle "merge"}} active selected{{end}}" data-do="merge">{{$.i18n.Tr "repo.pulls.merge_pull_request"}}</div>
+									{{end}}
+									{{if $prUnit.PullRequestsConfig.AllowRebase}}
+									<div class="item{{if eq .MergeStyle "rebase"}} active selected{{end}}" data-do="rebase">{{$.i18n.Tr "repo.pulls.rebase_merge_pull_request"}}</div>
+									{{end}}
+									{{if $prUnit.PullRequestsConfig.AllowSquash}}
+									<div class="item{{if eq .MergeStyle "squash"}} active selected{{end}}" data-do="squash">{{$.i18n.Tr "repo.pulls.squash_merge_pull_request"}}</div>
+									{{end}}
+								</div>
+							</div>
+						</div>
+					{{else}}
+						<div class="item text red">
+							<span class="octicon octicon-x"></span>
+							{{$.i18n.Tr "repo.pulls.no_merge_desc"}}
+						</div>
+						<div class="item text grey">
+							<span class="octicon octicon-info"></span>
+							{{$.i18n.Tr "repo.pulls.no_merge_helper"}}
+						</div>
+					{{end}}
 				{{end}}
 			{{else}}
 				<div class="item text red">
diff --git a/templates/repo/settings/options.tmpl b/templates/repo/settings/options.tmpl
index 41a91ea26e..3bc1a209f0 100644
--- a/templates/repo/settings/options.tmpl
+++ b/templates/repo/settings/options.tmpl
@@ -192,14 +192,41 @@
 
 				{{if .Repository.CanEnablePulls}}
 					<div class="ui divider"></div>
-
+					{{$pullRequestEnabled := .Repository.UnitEnabled $.UnitTypePullRequests}}
+					{{$prUnit := .Repository.MustGetUnit $.UnitTypePullRequests}}
 					<div class="inline field">
 						<label>{{.i18n.Tr "repo.pulls"}}</label>
 						<div class="ui checkbox">
-							<input name="enable_pulls" type="checkbox" {{if .Repository.UnitEnabled $.UnitTypePullRequests}}checked{{end}}>
+							<input class="enable-system" name="enable_pulls" type="checkbox" data-target="#pull_box" {{if $pullRequestEnabled}}checked{{end}}>
 							<label>{{.i18n.Tr "repo.settings.pulls_desc"}}</label>
 						</div>
 					</div>
+					<div class="field{{if not $pullRequestEnabled}} disabled{{end}}" id="pull_box">
+						<div class="field">
+							<div class="ui checkbox">
+								<input name="pulls_ignore_whitespace" type="checkbox" {{if and $pullRequestEnabled ($prUnit.PullRequestsConfig.IgnoreWhitespaceConflicts)}}checked{{end}}>
+								<label>{{.i18n.Tr "repo.settings.pulls.ignore_whitespace"}}</label>
+							</div>
+						</div>
+						<div class="field">
+							<div class="ui checkbox">
+								<input name="pulls_allow_merge" type="checkbox" {{if or (not $pullRequestEnabled) ($prUnit.PullRequestsConfig.AllowMerge)}}checked{{end}}>
+								<label>{{.i18n.Tr "repo.settings.pulls.allow_merge_commits"}}</label>
+							</div>
+						</div>
+						<div class="field">
+							<div class="ui checkbox">
+								<input name="pulls_allow_rebase" type="checkbox" {{if or (not $pullRequestEnabled) ($prUnit.PullRequestsConfig.AllowRebase)}}checked{{end}}>
+								<label>{{.i18n.Tr "repo.settings.pulls.allow_rebase_merge"}}</label>
+							</div>
+						</div>
+						<div class="field">
+							<div class="ui checkbox">
+								<input name="pulls_allow_squash" type="checkbox" {{if or (not $pullRequestEnabled) ($prUnit.PullRequestsConfig.AllowSquash)}}checked{{end}}>
+								<label>{{.i18n.Tr "repo.settings.pulls.allow_squash_commits"}}</label>
+							</div>
+						</div>
+					</div>
 				{{end}}
 
 				<div class="ui divider"></div>