Fix NPE on tags if repo has no tags

Author: puredanger

CHANGELOG.md

@@ -1,6 +1,8 @@
 Changelog
 ===========
 
+* next
+  * Fix NPE on tags if repo has no tags
 * 2.6.212 on Dec 30, 2025
   * Bump parent pom to latest
 * 2.6.206 on Dec 5, 2024

src/main/clojure/clojure/tools/gitlibs.clj

@@ -85,7 +85,7 @@
           (->> shas (sort (partial impl/commit-comparator git-dir)) first))))))
 
 (defn tags
-  "Fetches, then returns coll of tags in git url"
+  "Fetches, then returns coll of tags in git url, nil if none"
   [url]
   (impl/tags (impl/ensure-git-dir url)))
 
@@ -114,4 +114,8 @@
 
   ;; big output
   (tags "https://github.com/confluentinc/kafka-streams-examples.git")
+
+  ;; no tags
+  (tags "https://github.com/clojure/clojure-site.git")
+  (clojure.repl/pst *e)
   )

src/main/clojure/clojure/tools/gitlibs/impl.clj

@@ -206,4 +206,5 @@
   (let [{:keys [exit out err] :as ret} (run-git "--git-dir" git-dir "tag" "--sort=v:refname")]
     (when-not (zero? exit)
       (throw (ex-info (format "Unable to get tags %s%n%s" git-dir err) ret)))
-    (remove str/blank? (str/split-lines out))))
+    (when out
+      (remove str/blank? (str/split-lines out)))))