Make debug_info rules clear

Current rebar3 uses debug_info rules where debug_info is added by
default, and no_debug_info prevents the default from being added, and
removes any explicit debug_info, if any. The problem is that if
'no_debug_info' is anywhere in the config for a run, it cannot be
removed even with other profiles. additionally, no_debug_info ignores
special tuples like {debug_info, {Mod, Data}} and {debug_info_key, Key},
which can be used to add debug info and encrypt it (in lieu of plain
debug_info) respectively.

This patch makes it so that the following rules are in place:

- the last option seen takes priority, allowing profile overrides by
  the ordering rules the compiler expects
- the overriden options shall be explicitly deleted to avoid confusing
  the compiler
- any option related to debug info seen last cancels any no_debug_info
  that preceded it
- any no_debug_info option seen last cancels all of the other
  debug_info options
- if debug_info is seen last, it cancels out {debug_info_key, Key}
- if {debug_info_key, Key} is seen last, it cancels out debug_info
- All other options are left untouched in that context (defines can
  still be expanded and so on)

This should allow proper profile rules to be followed. Note that erl_opt
profile merging puts precedence on the *last* element of a list, to
match the compiler.

1 files changed, 26 insertions, 0 deletions

diff --git a/test/rebar_profiles_SUITE.erl b/test/rebar_profiles_SUITE.erl
index 324a771..6afdc39 100644
--- a/test/rebar_profiles_SUITE.erl
+++ b/test/rebar_profiles_SUITE.erl
@@ -27,6 +27,7 @@
          test_profile_erl_opts_order_3/1,
          test_profile_erl_opts_order_4/1,
          test_profile_erl_opts_order_5/1,
+         test_erl_opts_debug_info/1,
          first_files_exception/1]).
 
 -include_lib("common_test/include/ct.hrl").
@@ -50,6 +51,7 @@ all() ->
      test_profile_erl_opts_order_3,
      test_profile_erl_opts_order_4,
      test_profile_erl_opts_order_5,
+     test_erl_opts_debug_info,
      first_files_exception].
 
 init_per_suite(Config) ->
@@ -501,6 +503,30 @@ test_profile_erl_opts_order_5(Config) ->
     Opt = last_erl_opt(Opts, [warn_export_all, nowarn_export_all], undefined),
     warn_export_all = Opt.
 
+test_erl_opts_debug_info(_Config) ->
+    ToOpts = fun(List) -> rebar_opts:erl_opts(dict:from_list([{erl_opts, List}])) end,
+    ?assertEqual([debug_info,a,b,c],
+                 ToOpts([a,b,c])),
+    ?assertEqual([{debug_info,{mod,123}},a,b,c,debug_info],
+                 ToOpts([{debug_info,{mod,123}},a,b,c,debug_info])),
+    ?assertEqual([a,b,debug_info,c],
+                 ToOpts([no_debug_info,a,b,debug_info,c])),
+    ?assertEqual([a,b,c],
+                 ToOpts([debug_info,a,b,no_debug_info,c])),
+    ?assertEqual([a,b,c,debug_info],
+                 ToOpts([{debug_info_key, "12345"},a,b,
+                         no_debug_info,c,debug_info])),
+    ?assertEqual([a,b,c],
+                 ToOpts([{debug_info,{mod,123}},{debug_info_key, "12345"},
+                         a,no_debug_info,b,c,debug_info,no_debug_info])),
+    ?assertEqual([a,b,c,{debug_info_key,"123"}],
+                 ToOpts([{debug_info_key, "12345"},a,b,no_debug_info,debug_info,
+                         c,{debug_info_key, "123"}])),
+    ?assertEqual([{debug_info_key,"12345"},a,b,c,{debug_info,{mod,"123"}}],
+                 ToOpts([debug_info,{debug_info_key,"12345"},a,
+                         no_debug_info,b,c,{debug_info,{mod,"123"}}])),
+    ok.
+
 first_files_exception(_Config) ->
     RebarConfig = [{erl_first_files, ["c","a","b"]},
                    {mib_first_files, ["c","a","b"]},