rebar_xref: regression fixes and updates for a5be40c96

- restore support for "rebar help xref"
- update rebar.config.sample
- update 'help xref' string
- simplify new/changed functions by breaking out code or
  using simpler syntax where applicable

rebar.config.sample

@@ -209,7 +209,9 @@
 {xref_warnings, false}.
 
 %% xref checks to run
-{xref_checks, [exports_not_used, undefined_function_calls]}.
+{xref_checks, [undefined_function_calls, undefined_functions,
+               locals_not_used, exports_not_used,
+               deprecated_function_calls, deprecated_functions]}.
 
 %% Optional custom xref queries (xref manual has details) specified as
 %%     {xref_queries, [{query_string(), expected_query_result()},...]}

src/rebar_xref.erl

@@ -37,6 +37,9 @@
 
 -export([xref/2]).
 
+%% for internal use only
+-export([info/2]).
+
 %% ===================================================================
 %% Public API
 %% ===================================================================
@@ -65,7 +68,8 @@ xref(Config, _) ->
                       locals_not_used, exports_not_used,
                       deprecated_function_calls, deprecated_functions],
 
-    XrefChecks = sets:to_list(sets:intersection(sets:from_list(SupportedXrefs),
+    XrefChecks = sets:to_list(sets:intersection(
+                                sets:from_list(SupportedXrefs),
                                 sets:from_list(ConfXrefChecks))),
 
     %% Run xref checks
@@ -92,16 +96,36 @@ xref(Config, _) ->
 %% Internal functions
 %% ===================================================================
 
+info(help, xref) ->
+    ?CONSOLE(
+       "Run cross reference analysis.~n"
+       "~n"
+       "Valid rebar.config options:~n"
+       "  ~p~n"
+       "  ~p~n"
+       "  ~p~n",
+       [
+        {xref_warnings, false},
+        {xref_checks, [undefined_function_calls, undefined_functions,
+                       locals_not_used, exports_not_used,
+                       deprecated_function_calls, deprecated_functions]},
+        {xref_queries,
+         [{"(xc - uc) || (xu - x - b"
+           " - (\"mod\":\".*foo\"/\"4\"))",[]}]}
+       ]).
+
 xref_checks(XrefChecks) ->
-    XrefWarnCount = lists:foldl(
-        fun(XrefCheck, Acc) ->
+    XrefWarnCount = lists:foldl(fun run_xref_check/2, 0, XrefChecks),
+    XrefWarnCount =:= 0.
+
+run_xref_check(XrefCheck, Acc) ->
     {ok, Results} = xref:analyze(xref, XrefCheck),
     FilteredResults =filter_xref_results(XrefCheck, Results),
-            lists:foreach(fun(Res) -> display_xrefresult(XrefCheck, Res) end, FilteredResults),
-            Acc + length(FilteredResults)
+    lists:foreach(fun(Res) ->
+                          display_xref_result(XrefCheck, Res)
                   end,
-        0, XrefChecks),
-    XrefWarnCount =:= 0.
+                  FilteredResults),
+    Acc + length(FilteredResults).
 
 check_query({Query, Value}) ->
     {ok, Answer} = xref:q(xref, Query),
@@ -141,54 +165,51 @@ get_xref_ignorelist(Mod, XrefCheck) ->
             _Class:_Error -> []
         end,
 
-    Ignore_xref = keyall(ignore_xref, Attributes),
+    IgnoreXref = keyall(ignore_xref, Attributes),
 
-    Behaviour_callbacks = case XrefCheck of
-            exports_not_used -> [B:behaviour_info(callbacks) || B <- keyall(behaviour, Attributes)];
-            _ -> []
-    end,
+    BehaviourCallbacks = get_behaviour_callbacks(XrefCheck, Attributes),
 
-    % And create a flat {M,F,A} list
+    %% And create a flat {M,F,A} list
     lists:foldl(
-        fun(El,Acc) ->
-            case El of
-                {F, A} -> [{Mod,F,A} | Acc];
-                {M, F, A} -> [{M,F,A} | Acc]
-            end
-        end, [],lists:flatten([Ignore_xref, Behaviour_callbacks])).
+      fun({F, A}, Acc) -> [{Mod,F,A} | Acc];
+         ({M, F, A}, Acc) -> [{M,F,A} | Acc]
+      end, [], lists:flatten([IgnoreXref, BehaviourCallbacks])).
 
 keyall(Key, List) ->
     lists:flatmap(fun({K, L}) when Key =:= K -> L; (_) -> [] end, List).
 
-parse_xref_result(XrefResult) ->
-    case XrefResult of
-        {_, MFAt} -> MFAt;
-        MFAt -> MFAt
-    end.
+get_behaviour_callbacks(exports_not_used, Attributes) ->
+    [B:behaviour_info(callbacks) || B <- keyall(behaviour, Attributes)];
+get_behaviour_callbacks(_XrefCheck, _Attributes) ->
+    [].
+
+parse_xref_result({_, MFAt}) -> MFAt;
+parse_xref_result(MFAt) -> MFAt.
 
 filter_xref_results(XrefCheck, XrefResults) ->
-    SearchModules = lists:usort(lists:map(
-        fun(Res) ->
-            case Res of
-                {Mt,_Ft,_At} -> Mt;
-                {{Ms,_Fs,_As},{_Mt,_Ft,_At}} -> Ms;
-                _ -> undefined
-            end
+    SearchModules = lists:usort(
+                      lists:map(
+                        fun({Mt,_Ft,_At}) -> Mt;
+                           ({{Ms,_Fs,_As},{_Mt,_Ft,_At}}) -> Ms;
+                           (_) -> undefined
                         end, XrefResults)),
 
-    Ignores = lists:flatten([
-        get_xref_ignorelist(Module,XrefCheck) || Module <- SearchModules]),
+    Ignores = lists:flatmap(fun(Module) ->
+                                    get_xref_ignorelist(Module, XrefCheck)
+                            end, SearchModules),
 
     [Result || Result <- XrefResults,
                not lists:member(parse_xref_result(Result), Ignores)].
 
-display_xrefresult(Type, XrefResult) ->
+display_xref_result(Type, XrefResult) ->
     { Source, SMFA, TMFA } = case XrefResult of
                                  {MFASource, MFATarget} ->
-            {format_mfa_source(MFASource), format_mfa(MFASource),
+                                     {format_mfa_source(MFASource),
+                                      format_mfa(MFASource),
                                       format_mfa(MFATarget)};
                                  MFATarget ->
-            {format_mfa_source(MFATarget), format_mfa(MFATarget),
+                                     {format_mfa_source(MFATarget),
+                                      format_mfa(MFATarget),
                                       undefined}
                              end,
     case Type of
@@ -236,7 +257,6 @@ safe_element(N, Tuple) ->
             Value
     end.
 
-
 %%
 %% Given a MFA, find the file and LOC where it's defined. Note that
 %% xref doesn't work if there is no abstract_code, so we can avoid