builtins.fetchGit: document absolute ref support

1 files changed, 15 insertions, 0 deletions

diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml
index 412622714d..dcd7aaf243 100644
--- a/doc/manual/expressions/builtins.xml
+++ b/doc/manual/expressions/builtins.xml
@@ -419,6 +419,13 @@ stdenv.mkDerivation { … }
               This is often a branch or tag name. Defaults to
               <literal>HEAD</literal>.
             </para>
+
+            <para>
+              By default, the <varname>ref</varname> value is prefixed
+              with <literal>refs/heads/</literal>. As of Nix 2.3.0
+              Nix will not prefix <literal>refs/heads/</literal> if
+              <varname>ref</varname> starts with <literal>refs/</literal>.
+            </para>
           </listitem>
         </varlistentry>
       </variablelist>
@@ -433,6 +440,14 @@ stdenv.mkDerivation { … }
       </example>
 
       <example>
+        <title>Fetching an arbitrary ref</title>
+        <programlisting>builtins.fetchGit {
+  url = "https://gitub.com/NixOS/nix.git";
+  ref = "refs/heads/0.5-release";
+}</programlisting>
+      </example>
+
+      <example>
         <title>Fetching a repository's specific commit on an arbitrary branch</title>
         <para>
           If the revision you're looking for is in the default branch