Add ONLY_SHOW_RELEVANT_REPOS back, fix explore page bug, make code more strict (#23766)

Follow #21962

After I eat my own dogfood, I would say that
ONLY_SHOW_RELEVANT_REPOS=false is necessary for many private/enterprise
instances, because many private repositories do not have
"description/topic", users just want to search by their names.

This PR also adds `PageIsExploreRepositories` check, to make code more
strict, because the `search` template is shared for different purpose.

And during the test, I found a bug that the "Search" button didn't
respect the "relevant" parameter, so this PR fixes the bug by the way
together.

I think this PR needs to be backported.

5 files changed, 26 insertions, 6 deletions

diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index 5e0d16b042..2a840d5ef1 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -1238,6 +1238,10 @@ ROUTER = console
 ;;
 ;; Whether to enable a Service Worker to cache frontend assets
 ;USE_SERVICE_WORKER = false
+;;
+;; Whether to only show relevant repos on the explore page when no keyword is specified and default sorting is used.
+;; A repo is considered irrelevant if it's a fork or if it has no metadata (no description, no icon, no topic).
+;ONLY_SHOW_RELEVANT_REPOS = false
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
diff --git a/docs/content/doc/administration/config-cheat-sheet.en-us.md b/docs/content/doc/administration/config-cheat-sheet.en-us.md
index b62ec6f3ca..f8082bd378 100644
--- a/docs/content/doc/administration/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/administration/config-cheat-sheet.en-us.md
@@ -226,11 +226,13 @@ The following configuration set `Content-Type: application/vnd.android.package-a
     Values can be emoji alias (:smile:) or a unicode emoji.
     For custom reactions, add a tightly cropped square image to public/img/emoji/reaction_name.png
 - `CUSTOM_EMOJIS`: **gitea, codeberg, gitlab, git, github, gogs**: Additional Emojis not defined in the utf8 standard.
-    By default we support Gitea (:gitea:), to add more copy them to public/img/emoji/emoji_name.png and
+    By default, we support Gitea (:gitea:), to add more copy them to public/img/emoji/emoji_name.png and
     add it to this config.
 - `DEFAULT_SHOW_FULL_NAME`: **false**: Whether the full name of the users should be shown where possible. If the full name isn't set, the username will be used.
 - `SEARCH_REPO_DESCRIPTION`: **true**: Whether to search within description at repository search on explore page.
 - `USE_SERVICE_WORKER`: **false**: Whether to enable a Service Worker to cache frontend assets.
+- `ONLY_SHOW_RELEVANT_REPOS`: **false** Whether to only show relevant repos on the explore page when no keyword is specified and default sorting is used.
+    A repo is considered irrelevant if it's a fork or if it has no metadata (no description, no icon, no topic).
 
 ### UI - Admin (`ui.admin`)
 
diff --git a/modules/setting/ui.go b/modules/setting/ui.go
index 2df3c35c76..90bad50d3b 100644
--- a/modules/setting/ui.go
+++ b/modules/setting/ui.go
@@ -139,6 +139,9 @@ func loadUIFrom(rootCfg ConfigProvider) {
 	UI.DefaultShowFullName = sec.Key("DEFAULT_SHOW_FULL_NAME").MustBool(false)
 	UI.SearchRepoDescription = sec.Key("SEARCH_REPO_DESCRIPTION").MustBool(true)
 	UI.UseServiceWorker = sec.Key("USE_SERVICE_WORKER").MustBool(false)
+
+	// OnlyShowRelevantRepos=false is important for many private/enterprise instances,
+	// because many private repositories do not have "description/topic", users just want to search by their names.
 	UI.OnlyShowRelevantRepos = sec.Key("ONLY_SHOW_RELEVANT_REPOS").MustBool(false)
 
 	UI.ReactionsLookup = make(container.Set[string])
diff --git a/routers/web/explore/repo.go b/routers/web/explore/repo.go
index cc3af8cb2c..be5ad1b015 100644
--- a/routers/web/explore/repo.go
+++ b/routers/web/explore/repo.go
@@ -4,6 +4,7 @@
 package explore
 
 import (
+	"fmt"
 	"net/http"
 
 	"code.gitea.io/gitea/models/db"
@@ -18,7 +19,7 @@ import (
 const (
 	// tplExploreRepos explore repositories page template
 	tplExploreRepos        base.TplName = "explore/repos"
-	relevantReposOnlyParam string       = "no_filter"
+	relevantReposOnlyParam string       = "only_show_relevant"
 )
 
 // RepoSearchOptions when calling search repositories
@@ -137,7 +138,7 @@ func RenderRepoSearch(ctx *context.Context, opts *RepoSearchOptions) {
 	pager.SetDefaultParams(ctx)
 	pager.AddParam(ctx, "topic", "TopicOnly")
 	pager.AddParam(ctx, "language", "Language")
-	pager.AddParamString(relevantReposOnlyParam, ctx.FormString(relevantReposOnlyParam))
+	pager.AddParamString(relevantReposOnlyParam, fmt.Sprint(opts.OnlyShowRelevant))
 	ctx.Data["Page"] = pager
 
 	ctx.HTML(http.StatusOK, opts.TplName)
@@ -156,11 +157,18 @@ func Repos(ctx *context.Context) {
 		ownerID = ctx.Doer.ID
 	}
 
+	onlyShowRelevant := setting.UI.OnlyShowRelevantRepos
+
+	_ = ctx.Req.ParseForm() // parse the form first, to prepare the ctx.Req.Form field
+	if len(ctx.Req.Form[relevantReposOnlyParam]) != 0 {
+		onlyShowRelevant = ctx.FormBool(relevantReposOnlyParam)
+	}
+
 	RenderRepoSearch(ctx, &RepoSearchOptions{
 		PageSize:         setting.UI.ExplorePagingNum,
 		OwnerID:          ownerID,
 		Private:          ctx.Doer != nil,
 		TplName:          tplExploreRepos,
-		OnlyShowRelevant: !ctx.FormBool(relevantReposOnlyParam),
+		OnlyShowRelevant: onlyShowRelevant,
 	})
 }
diff --git a/templates/explore/repo_search.tmpl b/templates/explore/repo_search.tmpl
index 59d63b19d4..85c1be8e6e 100644
--- a/templates/explore/repo_search.tmpl
+++ b/templates/explore/repo_search.tmpl
@@ -26,12 +26,15 @@
 	<input type="hidden" name="language" value="{{$.Language}}">
 	<div class="ui fluid action input">
 		<input name="q" value="{{.Keyword}}" placeholder="{{.locale.Tr "explore.search"}}…" autofocus>
+		{{if .PageIsExploreRepositories}}
+			<input type="hidden" name="only_show_relevant" value="{{.OnlyShowRelevant}}">
+		{{end}}
 		<button class="ui primary button">{{.locale.Tr "explore.search"}}</button>
 	</div>
 </form>
-{{if .OnlyShowRelevant}}
+{{if and .PageIsExploreRepositories .OnlyShowRelevant}}
 	<div class="ui message explore-relevancy-note">
-		<span data-tooltip-content="{{.locale.Tr "explore.relevant_repositories_tooltip"}}">{{.locale.Tr "explore.relevant_repositories" ((printf "%s%s" $.Link "?no_filter=1")|Escape) | Safe}}</span>
+		<span data-tooltip-content="{{.locale.Tr "explore.relevant_repositories_tooltip"}}">{{.locale.Tr "explore.relevant_repositories" ((printf "%s%s" $.Link "?only_show_relevant=0")|Escape) | Safe}}</span>
 	</div>
 {{end}}
 <div class="ui divider"></div>