Use different git commands for different git versions

The option --single-branch was introduced in git version 1.7.10 and
thus rebar3 cannot fetch git dependencies on systems where earlier
git versions are install.

This commit will select other git clone commands if an earlier git
version is detected. If the git version cannot be determined rebar3
falls back on the previous behavior and uses --single-branch.

src/rebar_git_resource.erl

@@ -107,28 +107,50 @@ download(Dir, {git, Url, ""}, State) ->
     download(Dir, {git, Url, {branch, "master"}}, State);
 download(Dir, {git, Url, {branch, Branch}}, _State) ->
     ok = filelib:ensure_dir(Dir),
-    rebar_utils:sh(?FMT("git clone ~s ~s -b ~s --single-branch",
-                       [rebar_utils:escape_chars(Url),
-                        rebar_utils:escape_chars(filename:basename(Dir)),
-                        rebar_utils:escape_chars(Branch)]),
-                   [{cd, filename:dirname(Dir)}]);
+    git_clone(branch, git_vsn(), Url, Dir, Branch);
 download(Dir, {git, Url, {tag, Tag}}, _State) ->
     ok = filelib:ensure_dir(Dir),
-    rebar_utils:sh(?FMT("git clone ~s ~s -b ~s --single-branch",
-                       [rebar_utils:escape_chars(Url),
-                        rebar_utils:escape_chars(filename:basename(Dir)),
-                        rebar_utils:escape_chars(Tag)]),
-                   [{cd, filename:dirname(Dir)}]);
+    git_clone(tag, git_vsn(), Url, Dir, Tag);
 download(Dir, {git, Url, {ref, Ref}}, _State) ->
     ok = filelib:ensure_dir(Dir),
+    git_clone(ref, git_vsn(), Url, Dir, Ref);
+download(Dir, {git, Url, Rev}, _State) ->
+    ?WARN("WARNING: It is recommended to use {branch, Name}, {tag, Tag} or {ref, Ref}, otherwise updating the dep may not work as expected.", []),
+    ok = filelib:ensure_dir(Dir),
+    git_clone(rev, git_vsn(), Url, Dir, Rev).
+
+%% Use different git clone commands depending on git --version
+git_clone(branch,Vsn,Url,Dir,Branch) when Vsn >= {1,7,10}; Vsn =:= undefined ->
+    rebar_utils:sh(?FMT("git clone ~s ~s -b ~s --single-branch",
+                        [rebar_utils:escape_chars(Url),
+                         rebar_utils:escape_chars(filename:basename(Dir)),
+                         rebar_utils:escape_chars(Branch)]),
+                   [{cd, filename:dirname(Dir)}]);
+git_clone(branch,_Vsn,Url,Dir,Branch) ->
+    rebar_utils:sh(?FMT("git clone ~s ~s -b ~s",
+                        [rebar_utils:escape_chars(Url),
+                         rebar_utils:escape_chars(filename:basename(Dir)),
+                         rebar_utils:escape_chars(Branch)]),
+                   [{cd, filename:dirname(Dir)}]);
+git_clone(tag,Vsn,Url,Dir,Tag) when Vsn >= {1,7,10}; Vsn =:= undefined ->
+    rebar_utils:sh(?FMT("git clone ~s ~s -b ~s --single-branch",
+                        [rebar_utils:escape_chars(Url),
+                         rebar_utils:escape_chars(filename:basename(Dir)),
+                         rebar_utils:escape_chars(Tag)]),
+                   [{cd, filename:dirname(Dir)}]);
+git_clone(tag,_Vsn,Url,Dir,Tag) ->
+    rebar_utils:sh(?FMT("git clone ~s ~s -b ~s",
+                        [rebar_utils:escape_chars(Url),
+                         rebar_utils:escape_chars(filename:basename(Dir)),
+                         rebar_utils:escape_chars(Tag)]),
+                   [{cd, filename:dirname(Dir)}]);
+git_clone(ref,_Vsn,Url,Dir,Ref) ->
     rebar_utils:sh(?FMT("git clone -n ~s ~s",
                         [rebar_utils:escape_chars(Url),
                          rebar_utils:escape_chars(filename:basename(Dir))]),
                    [{cd, filename:dirname(Dir)}]),
     rebar_utils:sh(?FMT("git checkout -q ~s", [Ref]), [{cd, Dir}]);
-download(Dir, {git, Url, Rev}, _State) ->
-    ?WARN("WARNING: It is recommended to use {branch, Name}, {tag, Tag} or {ref, Ref}, otherwise updating the dep may not work as expected.", []),
-    ok = filelib:ensure_dir(Dir),
+git_clone(rev,_Vsn,Url,Dir,Rev) ->
     rebar_utils:sh(?FMT("git clone -n ~s ~s",
                         [rebar_utils:escape_chars(Url),
                          rebar_utils:escape_chars(filename:basename(Dir))]),
@@ -136,6 +158,30 @@ download(Dir, {git, Url, Rev}, _State) ->
     rebar_utils:sh(?FMT("git checkout -q ~s", [rebar_utils:escape_chars(Rev)]),
                    [{cd, Dir}]).
 
+git_vsn() ->
+    case application:get_env(rebar, git_vsn) of
+        {ok, Vsn} -> Vsn;
+        undefined ->
+            Vsn = git_vsn_fetch(),
+            application:set_env(rebar, git_vsn, Vsn),
+            Vsn
+    end.
+
+git_vsn_fetch() ->
+    case rebar_utils:sh("git --version",[]) of
+        {ok, VsnStr} ->
+            case re:run(VsnStr, "git version\\h+(\\d)\\.(\\d)\\.(\\d).*",[{capture,[1,2,3],list}]) of
+                {match,[Maj,Min,Patch]} ->
+                    {list_to_integer(Maj),
+                     list_to_integer(Min),
+                     list_to_integer(Patch)};
+                nomatch ->
+                    undefined
+            end;
+        {error, _} ->
+            undefined
+    end.
+
 make_vsn(Dir) ->
     case collect_default_refcount(Dir) of
         Vsn={plain, _} ->