A bad template index does not crash; shows warning

This should fix #955

The test is implicit as a bad index previously silently crashed rebar3.
By adding the bad index to the `new` suite's files, we can show that
things keep running.

src/rebar_prv_new.erl

@@ -7,6 +7,7 @@
          format_error/1]).
 
 -include("rebar.hrl").
+-include_lib("providers/include/providers.hrl").
 
 -define(PROVIDER, new).
 -define(DEPS, []).
@@ -35,16 +36,16 @@ do(State) ->
     case strip_flags(rebar_state:command_args(State)) of
         ["help"] ->
             ?CONSOLE("Call `rebar3 new help <template>` for a detailed description~n", []),
-            show_short_templates(rebar_templater:list_templates(State)),
+            show_short_templates(list_templates(State)),
             {ok, State};
         ["help", TemplateName] ->
-            case lists:keyfind(TemplateName, 1, rebar_templater:list_templates(State)) of
+            case lists:keyfind(TemplateName, 1, list_templates(State)) of
                 false -> ?CONSOLE("template not found.", []);
                 Term -> show_template(Term)
             end,
             {ok, State};
         [TemplateName | Opts] ->
-            case lists:keyfind(TemplateName, 1, rebar_templater:list_templates(State)) of
+            case lists:keyfind(TemplateName, 1, list_templates(State)) of
                 false ->
                     ?CONSOLE("template not found.", []);
                 _ ->
@@ -53,11 +54,13 @@ do(State) ->
             end,
             {ok, State};
         [] ->
-            show_short_templates(rebar_templater:list_templates(State)),
+            show_short_templates(list_templates(State)),
             {ok, State}
     end.
 
 -spec format_error(any()) -> iolist().
+format_error({consult, File, Reason}) ->
+    io_lib:format("Error consulting file at ~s for reason ~p", [File, Reason]);
 format_error(Reason) ->
     io_lib:format("~p", [Reason]).
 
@@ -65,6 +68,15 @@ format_error(Reason) ->
 %% Internal functions
 %% ===================================================================
 
+list_templates(State) ->
+    lists:foldl(fun({error, {consult, File, Reason}}, Acc) ->
+                    ?WARN("Error consulting template file ~s for reason ~p",
+                          [File, Reason]),
+                    Acc
+                ;  (Tpl, Acc) ->
+                    [Tpl|Acc]
+                end, [], lists:reverse(rebar_templater:list_templates(State))).
+
 info() ->
     io_lib:format(
       "Create rebar3 project based on template and vars.~n"

src/rebar_templater.erl

@@ -59,10 +59,14 @@ list_templates(State) ->
 
 %% Expand a single template's value
 list_template(Files, {Name, Type, File}, State) ->
-    TemplateTerms = consult(load_file(Files, Type, File)),
-    {Name, Type, File,
-     get_template_description(TemplateTerms),
-     get_template_vars(TemplateTerms, State)}.
+    case consult(load_file(Files, Type, File)) of
+        {error, Reason} ->
+            {error, {consult, File, Reason}};
+        TemplateTerms ->
+            {Name, Type, File,
+             get_template_description(TemplateTerms),
+             get_template_vars(TemplateTerms, State)}
+    end.
 
 %% Load up the template description out from a list of attributes read in
 %% a .template file.
@@ -338,8 +342,10 @@ consult(Cont, Str, Acc) ->
         {done, Result, Remaining} ->
             case Result of
                 {ok, Tokens, _} ->
-                    {ok, Term} = erl_parse:parse_term(Tokens),
-                    consult([], Remaining, [Term | Acc]);
+                    case erl_parse:parse_term(Tokens) of
+                        {ok, Term} -> consult([], Remaining, [Term | Acc]);
+                        {error, Reason} -> {error, Reason}
+                    end;
                 {eof, _Other} ->
                     lists:reverse(Acc);
                 {error, Info, _} ->

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/LICENSE.dtl

@@ -0,0 +1,29 @@
+Copyright (c) {{copyright_year}}, {{author_name}} <{{author_email}}>.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in the
+  documentation and/or other materials provided with the distribution.
+
+* The names of its contributors may not be used to endorse or promote
+  products derived from this software without specific prior written
+  permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/README.md.dtl

@@ -0,0 +1,9 @@
+{{name}}
+=====
+
+{{desc}}
+
+Build
+-----
+
+    $ rebar3 compile

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/app.erl.dtl

@@ -0,0 +1,27 @@
+%%%-------------------------------------------------------------------
+%% @doc {{name}} public API
+%% @end
+%%%-------------------------------------------------------------------
+
+-module({{name}}_app).
+
+-behaviour(application).
+
+%% Application callbacks
+-export([start/2
+        ,stop/1]).
+
+%%====================================================================
+%% API
+%%====================================================================
+
+start(_StartType, _StartArgs) ->
+    {{name}}_sup:start_link().
+
+%%--------------------------------------------------------------------
+stop(_State) ->
+    ok.
+
+%%====================================================================
+%% Internal functions
+%%====================================================================

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/bad_index.template

@@ -0,0 +1,13 @@
+{description, "OTP Application"}.
+{variables, [
+    {name, "mylib", "Name of the OTP application"},
+    {desc, "An OTP application", "Short description of the app"}
+]}.
+bad_term,
+{template, "app.erl.dtl", "{{name}}/src/{{name}}_app.erl"}.
+{template, "sup.erl.dtl", "{{name}}/src/{{name}}_sup.erl"}.
+{template, "otp_app.app.src.dtl", "{{name}}/src/{{name}}.app.src"}.
+{template, "rebar.config.dtl", "{{name}}/rebar.config"}.
+{template, "gitignore.dtl", "{{name}}/.gitignore"}.
+{template, "LICENSE.dtl", "{{name}}/LICENSE"}.
+{template, "README.md.dtl", "{{name}}/README.md"}.

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/gitignore.dtl

@@ -0,0 +1,18 @@
+.rebar3
+_*
+.eunit
+*.o
+*.beam
+*.plt
+*.swp
+*.swo
+.erlang.cookie
+ebin
+log
+erl_crash.dump
+.rebar
+_rel
+_deps
+_plugins
+_tdeps
+logs

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/otp_app.app.src.dtl

@@ -0,0 +1,12 @@
+{application, {{name}},
+ [{description, "{{desc}}"}
+ ,{vsn, "0.1.0"}
+ ,{registered, []}
+ ,{mod, {'{{name}}_app', []}}
+ ,{applications,
+   [kernel
+   ,stdlib
+   ]}
+ ,{env,[]}
+ ,{modules, []}
+ ]}.

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/rebar.config.dtl

@@ -0,0 +1,2 @@
+{erl_opts, [debug_info]}.
+{deps, []}.

test/rebar_new_SUITE_data/.rebar3/templates/bad_index/sup.erl.dtl

@@ -0,0 +1,35 @@
+%%%-------------------------------------------------------------------
+%% @doc {{name}} top level supervisor.
+%% @end
+%%%-------------------------------------------------------------------
+
+-module({{name}}_sup).
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+
+-define(SERVER, ?MODULE).
+
+%%====================================================================
+%% API functions
+%%====================================================================
+
+start_link() ->
+    supervisor:start_link({local, ?SERVER}, ?MODULE, []).
+
+%%====================================================================
+%% Supervisor callbacks
+%%====================================================================
+
+%% Child :: {Id,StartFunc,Restart,Shutdown,Type,Modules}
+init([]) ->
+    {ok, { {one_for_all, 0, 1}, []} }.
+
+%%====================================================================
+%% Internal functions
+%%====================================================================