Show outdated comments in files changed tab (#24936)

If enabled show a clickable label in the comment. A click on the label
opens the Conversation tab with the comment focussed - there you're able
to view the old diff (or original diff the comment was created on).

**Screenshots**


![image](https://github.com/go-gitea/gitea/assets/1135157/63ab9571-a9ee-4900-9f02-94ab0095f9e7)

![image](https://github.com/go-gitea/gitea/assets/1135157/78f7c225-8d76-46f5-acfd-9b8aab988a6c)



When resolved and outdated:

![image](https://github.com/go-gitea/gitea/assets/1135157/6ece9ebd-c792-4aa5-9c35-628694e9d093)

Option to enable/disable this (stored in user settings - default is
disabled):

![image](https://github.com/go-gitea/gitea/assets/1135157/ed99dfe4-76dc-4c12-bd96-e7e62da50ab5)

![image](https://github.com/go-gitea/gitea/assets/1135157/e837a052-e92e-4a28-906d-9db5bacf93a6)



fixes #24913

---------

Co-authored-by: silverwind <me@silverwind.io>

4 files changed, 30 insertions, 5 deletions

diff --git a/routers/web/repo/middlewares.go b/routers/web/repo/middlewares.go
index 5c38b31154..216550ca99 100644
--- a/routers/web/repo/middlewares.go
+++ b/routers/web/repo/middlewares.go
@@ -5,6 +5,7 @@ package repo
 
 import (
 	"fmt"
+	"strconv"
 
 	system_model "code.gitea.io/gitea/models/system"
 	user_model "code.gitea.io/gitea/models/user"
@@ -88,3 +89,27 @@ func SetWhitespaceBehavior(ctx *context.Context) {
 		ctx.Data["WhitespaceBehavior"] = whitespaceBehavior
 	}
 }
+
+// SetShowOutdatedComments set the show outdated comments option as context variable
+func SetShowOutdatedComments(ctx *context.Context) {
+	showOutdatedCommentsValue := ctx.FormString("show-outdated")
+	// var showOutdatedCommentsValue string
+
+	if showOutdatedCommentsValue != "true" && showOutdatedCommentsValue != "false" {
+		// invalid or no value for this form string -> use default or stored user setting
+		if ctx.IsSigned {
+			showOutdatedCommentsValue, _ = user_model.GetUserSetting(ctx.Doer.ID, user_model.SettingsKeyShowOutdatedComments, "false")
+		} else {
+			// not logged in user -> use the default value
+			showOutdatedCommentsValue = "false"
+		}
+	} else {
+		// valid value -> update user setting if user is logged in
+		if ctx.IsSigned {
+			_ = user_model.SetUserSetting(ctx.Doer.ID, user_model.SettingsKeyShowOutdatedComments, showOutdatedCommentsValue)
+		}
+	}
+
+	showOutdatedComments, _ := strconv.ParseBool(showOutdatedCommentsValue)
+	ctx.Data["ShowOutdatedComments"] = showOutdatedComments
+}
diff --git a/routers/web/repo/pull.go b/routers/web/repo/pull.go
index ef9d5856da..f2a58a35a7 100644
--- a/routers/web/repo/pull.go
+++ b/routers/web/repo/pull.go
@@ -761,7 +761,7 @@ func ViewPullFiles(ctx *context.Context) {
 		"numberOfViewedFiles": diff.NumViewedFiles,
 	}
 
-	if err = diff.LoadComments(ctx, issue, ctx.Doer); err != nil {
+	if err = diff.LoadComments(ctx, issue, ctx.Doer, ctx.Data["ShowOutdatedComments"].(bool)); err != nil {
 		ctx.ServerError("LoadComments", err)
 		return
 	}
diff --git a/routers/web/repo/pull_review.go b/routers/web/repo/pull_review.go
index 69d36ff4a4..5aa5811367 100644
--- a/routers/web/repo/pull_review.go
+++ b/routers/web/repo/pull_review.go
@@ -159,7 +159,7 @@ func UpdateResolveConversation(ctx *context.Context) {
 }
 
 func renderConversation(ctx *context.Context, comment *issues_model.Comment) {
-	comments, err := issues_model.FetchCodeCommentsByLine(ctx, comment.Issue, ctx.Doer, comment.TreePath, comment.Line)
+	comments, err := issues_model.FetchCodeCommentsByLine(ctx, comment.Issue, ctx.Doer, comment.TreePath, comment.Line, ctx.Data["ShowOutdatedComments"].(bool))
 	if err != nil {
 		ctx.ServerError("FetchCodeCommentsByLine", err)
 		return
diff --git a/routers/web/web.go b/routers/web/web.go
index a7573b38f5..26ad2d54c3 100644
--- a/routers/web/web.go
+++ b/routers/web/web.go
@@ -1037,7 +1037,7 @@ func registerRoutes(m *web.Route) {
 			m.Post("/dismiss_review", reqRepoAdmin, web.Bind(forms.DismissReviewForm{}), repo.DismissReview)
 			m.Post("/status", reqRepoIssuesOrPullsWriter, repo.UpdateIssueStatus)
 			m.Post("/delete", reqRepoAdmin, repo.BatchDeleteIssues)
-			m.Post("/resolve_conversation", reqRepoIssuesOrPullsReader, repo.UpdateResolveConversation)
+			m.Post("/resolve_conversation", reqRepoIssuesOrPullsReader, repo.SetShowOutdatedComments, repo.UpdateResolveConversation)
 			m.Post("/attachments", repo.UploadIssueAttachment)
 			m.Post("/attachments/remove", repo.DeleteAttachment)
 			m.Delete("/unpin/{index}", reqRepoAdmin, repo.IssueUnpin)
@@ -1285,10 +1285,10 @@ func registerRoutes(m *web.Route) {
 			m.Post("/set_allow_maintainer_edit", web.Bind(forms.UpdateAllowEditsForm{}), repo.SetAllowEdits)
 			m.Post("/cleanup", context.RepoMustNotBeArchived(), context.RepoRef(), repo.CleanUpPullRequest)
 			m.Group("/files", func() {
-				m.Get("", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.ViewPullFiles)
+				m.Get("", context.RepoRef(), repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.SetShowOutdatedComments, repo.ViewPullFiles)
 				m.Group("/reviews", func() {
 					m.Get("/new_comment", repo.RenderNewCodeCommentForm)
-					m.Post("/comments", web.Bind(forms.CodeCommentForm{}), repo.CreateCodeComment)
+					m.Post("/comments", web.Bind(forms.CodeCommentForm{}), repo.SetShowOutdatedComments, repo.CreateCodeComment)
 					m.Post("/submit", web.Bind(forms.SubmitReviewForm{}), repo.SubmitReview)
 				}, context.RepoMustNotBeArchived())
 			})