fix: go get fails with GO_GET_CLONE_URL_PROTOCOL=ssh on the default SSH port (#39674)

Go rejects scp-style addresses like `git@host:owner/repo.git` in the
go-import meta tag because they have no URL scheme, so
GO_GET_CLONE_URL_PROTOCOL=ssh did not work with the default SSH port
unless USE_COMPAT_SSH_URI was set. Always use the ssh:// form for
go-get.

When DISABLE_HTTP_GIT is enabled, the https clone URL can never work, so
GO_GET_CLONE_URL_PROTOCOL now defaults to ssh in that case.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

services/context/repo.go

@@ -389,6 +389,15 @@ func ComposeGoGetImport(ctx context.Context, owner, repo string) string {
 	return path.Join(curAppURL.Host, setting.AppSubURL, url.PathEscape(owner), url.PathEscape(repo))
 }
 
+// ComposeGoGetCloneURL returns the clone URL for the go-import meta content.
+func ComposeGoGetCloneURL(ctx *Context, owner, repo string) string {
+	useSSH := setting.Repository.GoGetCloneURLProtocol == "ssh" || (setting.Repository.DisableHTTPGit && !setting.SSH.Disabled)
+	if useSSH {
+		return repo_model.ComposeSSHCloneURI(ctx.Doer, owner, repo)
+	}
+	return repo_model.ComposeHTTPSCloneURL(ctx, owner, repo)
+}
+
 // EarlyResponseForGoGetMeta responses appropriate go-get meta with status 200
 // if user does not have actual access to the requested repository,
 // or the owner or repository does not exist at all.
@@ -402,13 +411,7 @@ func EarlyResponseForGoGetMeta(ctx *Context) {
 		return
 	}
 
-	var cloneURL string
-	if setting.Repository.GoGetCloneURLProtocol == "ssh" {
-		cloneURL = repo_model.ComposeSSHCloneURL(ctx.Doer, username, reponame)
-	} else {
-		cloneURL = repo_model.ComposeHTTPSCloneURL(ctx, username, reponame)
-	}
-	goImportContent := fmt.Sprintf("%s git %s", ComposeGoGetImport(ctx, username, reponame), cloneURL)
+	goImportContent := fmt.Sprintf("%s git %s", ComposeGoGetImport(ctx, username, reponame), ComposeGoGetCloneURL(ctx, username, reponame))
 	htmlMeta := fmt.Sprintf(`<meta name="go-import" content="%s">`, html.EscapeString(goImportContent))
 	ctx.PlainText(http.StatusOK, htmlMeta)
 }