Add new object-type api method

Author: puredanger

CHANGELOG.md

@@ -1,6 +1,8 @@
 Changelog
 ===========
 
+* next
+  * Add new `object-type` api - takes rev, returns object type
 * 2.2.156 on Apr 7, 2021
   * `tags` api should fetch to ensure all tags are returned
 * 2.2.152 on Apr 3, 2021

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

@@ -47,6 +47,17 @@
   [url rev]
   (first (resolve-all url [rev])))
 
+(defn object-type
+  "Takes a git url and rev, and returns the object type, one of :tag :tree
+  :commit or :blob, or nil if not known or ambiguous."
+  [url rev]
+  (let [git-dir (impl/ensure-git-dir url)]
+    (if-let [type (impl/git-type git-dir rev)]
+      type
+      (do
+        (impl/git-fetch (jio/file git-dir))
+        (impl/git-type git-dir rev)))))
+
 (defn procure
   "Procure a working tree at rev for the git url representing the library lib,
   returns the directory path. lib is a qualified symbol where the qualifier is a

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

@@ -102,6 +102,12 @@
     (when (zero? exit)
       (str/trimr out))))
 
+(defn git-type
+  [git-dir rev]
+  (let [{:keys [exit out]} (run-git "--git-dir" git-dir "cat-file" "-t" rev)]
+    (when (zero? exit)
+      (keyword (str/trimr out)))))
+
 ;; git merge-base --is-ancestor <maybe-ancestor-commit> <descendant-commit> 
 (defn- ancestor?
   [git-dir x y]