delete all symlinks when copying from project files to `_build` tree

to prevent any data from being overwritten

fixes #395

src/rebar_prv_common_test.erl

@@ -275,23 +275,25 @@ find_suite_dirs(Suites) ->
     %% eliminate duplicates
     lists:usort(AllDirs).
 
-copy(State, Target) ->
-    case reduce_path(Target) == rebar_state:dir(State) of
+copy(State, Dir) ->
+    From = reduce_path(Dir),
+    case From == rebar_state:dir(State) of
         true  -> throw({error, suite_at_project_root});
         false -> ok
     end,
-    case retarget_path(State, Target) of
+    case retarget_path(State, From) of
         %% directory lies outside of our project's file structure so
         %%  don't copy it
-        Target    -> Target;
-        NewTarget ->
-            %% unlink the directory if it's a symlink
-            case ec_file:is_symlink(NewTarget) of
-                true  -> ok = ec_file:remove(NewTarget);
+        From   -> From;
+        Target ->
+            %% recursively delete any symlinks in the target directory
+            %%  if it exists so we don't smash files in the linked dirs
+            case ec_file:is_dir(Target) of
+                true  -> remove_links(Target);
                 false -> ok
             end,
-            ok = ec_file:copy(Target, NewTarget, [recursive]),
-            NewTarget
+            ok = ec_file:copy(From, Target, [recursive]),
+            Target
     end.
 
 compile_dir(State, Dir) ->
@@ -338,6 +340,26 @@ reduce_path([_|Acc], [".."|Rest])  -> reduce_path(Acc, Rest);
 reduce_path([], [".."|Rest])       -> reduce_path([], Rest);
 reduce_path(Acc, [Component|Rest]) -> reduce_path([Component|Acc], Rest).
 
+remove_links(Path) ->
+    case ec_file:is_dir(Path) of
+        false -> ok;
+        true  -> remove_links1(Path)
+    end.
+
+remove_links1(Path) ->
+    case ec_file:is_symlink(Path) of
+        true  ->
+            file:delete(Path);
+        false ->
+            lists:foreach(fun(ChildPath) ->
+                                  remove_links(ChildPath)
+                          end, sub_dirs(Path))
+    end.
+
+sub_dirs(Path) ->
+    {ok, SubDirs} = file:list_dir(Path),
+    [filename:join(Path, SubDir) || SubDir <- SubDirs].
+
 replace_src_dirs(State, Dirs) ->
     %% replace any `src_dirs` with the test dirs
     ErlOpts = rebar_state:get(State, erl_opts, []),

test/rebar_ct_SUITE.erl

@@ -16,7 +16,8 @@
          single_unmanaged_suite/1,
          multi_suite/1,
          all_suite/1,
-         single_dir_and_single_suite/1]).
+         single_dir_and_single_suite/1,
+         symlinked_dir_overwritten_fix/1]).
 
 -include_lib("common_test/include/ct.hrl").
 
@@ -36,7 +37,8 @@ groups() -> [{basic_app, [], [basic_app_default_dirs,
                                     single_unmanaged_suite,
                                     multi_suite,
                                     all_suite,
-                                    single_dir_and_single_suite]}].
+                                    single_dir_and_single_suite,
+                                    symlinked_dir_overwritten_fix]}].
 
 init_per_group(basic_app, Config) ->
     C = rebar_test_utils:init_rebar_state(Config, "ct_"),
@@ -513,6 +515,36 @@ single_dir_and_single_suite(Config) ->
 
     Expect = Suite.
 
+symlinked_dir_overwritten_fix(Config) ->
+    AppDir = ?config(apps, Config),
+    [Name1, _Name2] = ?config(appnames, Config),
+
+    {ok, State} = rebar_test_utils:run_and_check(Config, [], ["as", "test", "compile"], return),
+
+    LibDirs = rebar_dir:lib_dirs(State),
+    State1 = rebar_app_discover:do(State, LibDirs),
+
+    Providers = rebar_state:providers(State1),
+    Namespace = rebar_state:namespace(State1),
+    CommandProvider = providers:get_provider(ct, Providers, Namespace),
+    GetOptSpec = providers:opts(CommandProvider),
+    {ok, GetOptResult} = getopt:parse(GetOptSpec,
+                                      ["--dir=" ++ filename:join([AppDir,
+                                                                  "apps",
+                                                                  Name1])]),
+
+    State2 = rebar_state:command_parsed_args(State1, GetOptResult),
+
+    Result = rebar_prv_common_test:setup_ct(State2),
+
+    Expect = filename:absname(filename:join([AppDir, "_build", "test", "lib", Name1])),
+    Dir = proplists:get_value(dir, Result),
+
+    Expect = Dir,
+
+    {ok, _} = rebar_test_utils:run_and_check(Config, [], ["as", "test", "compile"], return).
+
+
 test_suite(Name) ->
     io_lib:format("-module(~ts_SUITE).\n"
                   "-compile(export_all).\n"