6 files changed, 107 insertions, 4 deletions
diff --git a/doc/manual/command-ref/nix-store.xml b/doc/manual/command-ref/nix-store.xml
index 2ecc63db7c29..113a3c2e41ed 100644
--- a/doc/manual/command-ref/nix-store.xml
+++ b/doc/manual/command-ref/nix-store.xml
@@ -925,6 +925,60 @@ $ nix-store --add ./foo.c
 
 </refsection>
 
+<!--######################################################################-->
+
+<refsection><title>Operation <option>--add-fixed</option></title>
+
+<refsection><title>Synopsis</title>
+
+<cmdsynopsis>
+  <command>nix-store</command>
+  <arg><option>--recursive</option></arg>
+  <arg choice='plain'><option>--add-fixed</option></arg>
+  <arg choice='plain'><replaceable>algorithm</replaceable></arg>
+  <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg>
+</cmdsynopsis>
+
+</refsection>
+
+<refsection><title>Description</title>
+
+<para>The operation <option>--add-fixed</option> adds the specified paths to
+the Nix store.  Unlike <option>--add</option> paths are registered using the
+specified hashing algorithm, resulting in the same output path as a fixed output
+derivation.  This can be used for sources that are not available from a public
+url or broke since the download expression was written.
+</para>
+
+<para>This operation has the following options:
+
+<variablelist>
+
+  <varlistentry><term><option>--recursive</option></term>
+
+    <listitem><para>
+      Use recursive instead of flat hashing mode, used when adding directories
+      to the store.
+    </para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</para>
+
+</refsection>
+
+<refsection><title>Example</title>
+
+<screen>
+$ nix-store --add-fixed sha256 ./hello-2.10.tar.gz
+/nix/store/3x7dwzq014bblazs7kq20p9hyzz0qh8g-hello-2.10.tar.gz</screen>
+
+</refsection>
+
+</refsection>
+
 
 
 <!--######################################################################-->
diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml
index a87639a075a5..69123fff0e2e 100644
--- a/doc/manual/expressions/builtins.xml
+++ b/doc/manual/expressions/builtins.xml
@@ -425,6 +425,13 @@ 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>
@@ -439,6 +446,14 @@ 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
diff --git a/doc/manual/release-notes/release-notes.xml b/doc/manual/release-notes/release-notes.xml
index e8ff586fa43f..2655d68e354b 100644
--- a/doc/manual/release-notes/release-notes.xml
+++ b/doc/manual/release-notes/release-notes.xml
@@ -12,6 +12,7 @@
 </partintro>
 -->
 
+<xi:include href="rl-2.3.xml" />
 <xi:include href="rl-2.2.xml" />
 <xi:include href="rl-2.1.xml" />
 <xi:include href="rl-2.0.xml" />
diff --git a/doc/manual/release-notes/rl-2.3.xml b/doc/manual/release-notes/rl-2.3.xml
new file mode 100644
index 000000000000..428213b360ba
--- /dev/null
+++ b/doc/manual/release-notes/rl-2.3.xml
@@ -0,0 +1,22 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-relnotes-2.3">
+
+<title>Release 2.3 (????-??-??)</title>
+
+<para>This release contains the following changes:</para>
+
+<itemizedlist>
+
+  <listitem>
+    <para><function>builtins.fetchGit</function>'s <varname>ref</varname>
+    argument now allows specifying an absolute remote ref.
+    Nix will automatically prefix <varname>ref</varname> with
+    <literal>refs/heads</literal> only if <varname>ref</varname> doesn't
+    already begin with <literal>refs/</literal>.
+    </para>
+  </listitem>
+</itemizedlist>
+</section>
diff --git a/src/libexpr/primops/fetchGit.cc b/src/libexpr/primops/fetchGit.cc
index 3dcf3e9ff862..6229fef8d02e 100644
--- a/src/libexpr/primops/fetchGit.cc
+++ b/src/libexpr/primops/fetchGit.cc
@@ -94,7 +94,11 @@ GitInfo exportGit(ref<Store> store, const std::string & uri,
         runProgram("git", true, { "init", "--bare", cacheDir });
     }
 
-    Path localRefFile = cacheDir + "/refs/heads/" + *ref;
+    Path localRefFile;
+    if (ref->compare(0, 5, "refs/") == 0)
+        localRefFile = cacheDir + "/" + *ref;
+    else
+        localRefFile = cacheDir + "/refs/heads/" + *ref;
 
     bool doFetch;
     time_t now = time(0);
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 28ad7c019a94..92f01fd2e0c7 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -86,18 +86,25 @@ string storePathToHash(const Path & path)
 void checkStoreName(const string & name)
 {
     string validChars = "+-._?=";
+
+    auto baseError = format("The path name '%2%' is invalid: %3%. "
+        "Path names are alphanumeric and can include the symbols %1% "
+        "and must not begin with a period. "
+        "Note: If '%2%' is a source file and you cannot rename it on "
+        "disk, builtins.path { name = ... } can be used to give it an "
+        "alternative name.") % validChars % name;
+
     /* Disallow names starting with a dot for possible security
        reasons (e.g., "." and ".."). */
     if (string(name, 0, 1) == ".")
-        throw Error(format("illegal name: '%1%'") % name);
+        throw Error(baseError % "it is illegal to start the name with a period");
     for (auto & i : name)
         if (!((i >= 'A' && i <= 'Z') ||
               (i >= 'a' && i <= 'z') ||
               (i >= '0' && i <= '9') ||
               validChars.find(i) != string::npos))
         {
-            throw Error(format("invalid character '%1%' in name '%2%'")
-                % i % name);
+            throw Error(baseError % (format("the '%1%' character is invalid") % i));
         }
 }