Tell dialyzer not to warn about unused functions

Depending on the dictionary, generated dictionary modules may contain
unused functions included from diameter_gen.hrl. There may still be
warnings however since even used functions can contain code that
isn't reached for a given dictionary.

It would be useful for diameter to generate spec attributes for
a dictionary's generated records but the format of these is currently
undocumented.

4 files changed, 44 insertions, 1 deletions

diff --git a/lib/diameter/src/compiler/diameter_codegen.erl b/lib/diameter/src/compiler/diameter_codegen.erl
index 489f521f70..1e31c40afe 100644
--- a/lib/diameter/src/compiler/diameter_codegen.erl
+++ b/lib/diameter/src/compiler/diameter_codegen.erl
@@ -129,7 +129,7 @@ gen(hrl, Spec, Mod, Path) ->
 gen(erl, Spec, Mod, Path) ->
     Forms = [{?attribute, module, Mod},
              {?attribute, compile, [{parse_transform, diameter_exprecs}]},
-             {?attribute, compile, [nowarn_unused_function]},
+             {?attribute, compile, [{parse_transform, diameter_nowarn}]},
              {?attribute, export, [{name, 0},
                                    {id, 0},
                                    {vendor_id, 0},
diff --git a/lib/diameter/src/compiler/diameter_nowarn.erl b/lib/diameter/src/compiler/diameter_nowarn.erl
new file mode 100644
index 0000000000..6c17af6563
--- /dev/null
+++ b/lib/diameter/src/compiler/diameter_nowarn.erl
@@ -0,0 +1,41 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2010-2011. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%
+%% A parse transform to work around dialyzer currently not
+%% understanding nowarn_unused_function except on individual
+%% functions. The include of diameter_gen.hrl by generated dictionary
+%% modules contains code that may not be called depending on the
+%% dictionary. (The relay dictionary for example.)
+%%
+%% Even called functions may contain cases that aren't used for a
+%% particular dictionary. This also causes dialyzer to complain but
+%% there's no way to silence it in this case.
+%%
+
+-module(diameter_nowarn).
+
+-export([parse_transform/2]).
+
+parse_transform(Forms, _Options) ->
+    [{attribute, ?LINE, compile, {nowarn_unused_function, {F,A}}}
+     || {function, _, F, A, _} <- Forms]
+    ++ Forms.
+%% Note that dialyzer also doesn't understand {nowarn_unused_function, FAs}
+%% with FAs a list of tuples.
diff --git a/lib/diameter/src/modules.mk b/lib/diameter/src/modules.mk
index c5d448b2ff..11d354e57e 100644
--- a/lib/diameter/src/modules.mk
+++ b/lib/diameter/src/modules.mk
@@ -66,6 +66,7 @@ CT_MODULES = \
 	base/diameter_info \
 	compiler/diameter_codegen \
 	compiler/diameter_exprecs \
+	compiler/diameter_nowarn \
 	compiler/diameter_dict_scanner \
 	compiler/diameter_dict_util \
 	compiler/diameter_make
diff --git a/lib/diameter/test/diameter_app_SUITE.erl b/lib/diameter/test/diameter_app_SUITE.erl
index 808f2cd30d..53332af626 100644
--- a/lib/diameter/test/diameter_app_SUITE.erl
+++ b/lib/diameter/test/diameter_app_SUITE.erl
@@ -48,6 +48,7 @@
                            diameter_dict_parser,
                            diameter_dict_util,
                            diameter_exprecs,
+                           diameter_nowarn,
                            diameter_make]).
 
 -define(HELP_MODULES, [diameter_dbg,