Added support for fetching latest release from GitLab (#7418)

* Fetch version for GitLab repositories

* Update documentation about repositories

* Fix code formatting

docs/setup/adding-a-git-repository.md

@@ -22,20 +22,25 @@ repo_url: https://github.com/squidfunk/mkdocs-material
 
 The link to the repository will be rendered next to the search bar on big
 screens and as part of the main navigation drawer on smaller screen sizes.
-Additionally, for public repositories hosted on [GitHub] or [GitLab], the
-number of stars and forks is automatically requested and rendered.
 
-GitHub repositories also include the tag of the latest release.[^1]
+Additionally, for public repositories hosted on [GitHub] or [GitLab], the
+latest release tag[^1], as well as the number of stars and forks, are
+automatically requested and rendered.
 
   [^1]:
     Unfortunately, GitHub only provides an API endpoint to obtain the [latest
     release] - not the latest tag. Thus, make sure to [create a release] (not
     pre-release) for the latest tag you want to display next to the number of
-    stars and forks.
+    stars and forks. For GitLab, although it is possible to get a [list of tags
+    sorted by update time], the [equivalent API endpoint] is used. So, make sure
+    you also [create a release for GitLab repositories].
 
   [repo_url]: https://www.mkdocs.org/user-guide/configuration/#repo_url
   [latest release]: https://docs.github.com/en/rest/reference/releases#get-the-latest-release
   [create a release]: https://docs.github.com/en/repositories/releasing-projects-on-github/managing-releases-in-a-repository#creating-a-release
+  [list of tags sorted by update time]: https://docs.gitlab.com/ee/api/tags.html#list-project-repository-tags
+  [equivalent API endpoint]: https://docs.gitlab.com/ee/api/releases/#get-the-latest-release
+  [create a release for GitLab repositories]: https://docs.gitlab.com/ee/user/project/releases/#create-a-release
 
 #### Repository name
 

src/templates/assets/javascripts/components/source/facts/gitlab/index.ts

@@ -26,13 +26,25 @@ import {
   Observable,
   catchError,
   defaultIfEmpty,
-  map
+  map,
+  zip
 } from "rxjs"
 
 import { requestJSON } from "~/browser"
 
 import { SourceFacts } from "../_"
 
+/* ----------------------------------------------------------------------------
+ * Helper types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * GitLab release (partial)
+ */
+interface Release { // @todo remove and use the ReleaseSchema type instead after switching from gitlab to @gitbeaker/rest
+  tag_name: string                     /* Tag name */
+}
+
 /* ----------------------------------------------------------------------------
  * Functions
  * ------------------------------------------------------------------------- */
@@ -49,13 +61,30 @@ export function fetchSourceFactsFromGitLab(
   base: string, project: string
 ): Observable<SourceFacts> {
   const url = `https://${base}/api/v4/projects/${encodeURIComponent(project)}`
-  return requestJSON<ProjectSchema>(url)
+  return zip(
+
+    /* Fetch version */
+    requestJSON<Release>(`${url}/releases/permalink/latest`)
+      .pipe(
+        catchError(() => EMPTY), // @todo refactor instant loading
+        map(({ tag_name }) => ({
+          version: tag_name
+        })),
+        defaultIfEmpty({})
+      ),
+
+    /* Fetch stars and forks */
+    requestJSON<ProjectSchema>(url)
+      .pipe(
+        catchError(() => EMPTY), // @todo refactor instant loading
+        map(({ star_count, forks_count }) => ({
+          stars: star_count,
+          forks: forks_count
+        })),
+        defaultIfEmpty({})
+      )
+  )
     .pipe(
-      catchError(() => EMPTY), // @todo refactor instant loading
-      map(({ star_count, forks_count }) => ({
-        stars: star_count,
-        forks: forks_count
-      })),
-      defaultIfEmpty({})
+      map(([release, info]) => ({ ...release, ...info }))
     )
 }