From 9a9f2d2024506efcea72b0979946ffb23ad99eff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pablo=20Costas=20S=C3=A1nchez?=
 <pablo.costas.sanchez@gmail.com>
Date: Mon, 5 Oct 2020 20:22:14 +0200
Subject: [PATCH 1/2] Make rebar3 templates check for name clashes

This commit changes rebar3 to check for name clashes of the
modules created from its templates with existing Erlang modules
to produce a non-blocking warning for each clashing module.
---
 src/rebar_templater.erl | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/rebar_templater.erl b/src/rebar_templater.erl
index 6acccc52..c8d743fe 100644
--- a/src/rebar_templater.erl
+++ b/src/rebar_templater.erl
@@ -196,6 +196,21 @@ maybe_warn_about_name(Vars) ->
             ok
     end.
 
+maybe_warn_about_name_clash(File) ->
+    case filename:extension(File) of
+        ".erl" ->
+            Module0 = re:replace(filename:basename(File), "\.erl", "", [{return, list}]),
+            Module = list_to_atom(Module0),
+            try Module:module_info() of
+                _ -> ?WARN("The module definition of '~ts' in file ~ts "
+                           "will clash with an existing Erlang module.",
+                           [Module, File])
+            catch
+                _:_ -> ok
+            end;
+        _ -> ok
+    end.
+
 validate_atom(Str) ->
     case io_lib:fread("~a", unicode:characters_to_list(Str)) of
         {ok, [Atom], ""} ->
@@ -258,6 +273,7 @@ execute_template([{template, From, To} | Terms], Files, {Template, Type, Cwd}, V
     In = expand_path(From, Vars),
     Out = expand_path(To, Vars),
     Tpl = load_file(Files, Type, filename:join(Cwd, In)),
+    maybe_warn_about_name_clash(Out),
     case write_file(Out, render(Tpl, Vars), Force) of
         ok ->
             ok;

From a1d17fce6a2648cb05977163bfb549dc419b2077 Mon Sep 17 00:00:00 2001
From: Pablo Costas <pablo.costas.sanchez@gmail.com>
Date: Tue, 6 Oct 2020 22:59:57 +0200
Subject: [PATCH 2/2] Update rebar_templater with safer regex

Co-authored-by: Fred Hebert <mononcqc@ferd.ca>
---
 src/rebar_templater.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/rebar_templater.erl b/src/rebar_templater.erl
index c8d743fe..001f6b1c 100644
--- a/src/rebar_templater.erl
+++ b/src/rebar_templater.erl
@@ -199,7 +199,7 @@ maybe_warn_about_name(Vars) ->
 maybe_warn_about_name_clash(File) ->
     case filename:extension(File) of
         ".erl" ->
-            Module0 = re:replace(filename:basename(File), "\.erl", "", [{return, list}]),
+            Module0 = re:replace(filename:basename(File), "\\.erl$", "", [{return, list}]),
             Module = list_to_atom(Module0),
             try Module:module_info() of
                 _ -> ?WARN("The module definition of '~ts' in file ~ts "