rebar3/src/rebar_prv_xref.erl

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2021-12-27 19:09:21 +00:00
%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 et
-module(rebar_prv_xref).
-behaviour(provider).
-export([init/1,
do/1,
format_error/1,
filter_xref_results/3]).
-include("rebar.hrl").
-include_lib("providers/include/providers.hrl").
-define(PROVIDER, xref).
-define(DEPS, [compile]).
-define(SUPPORTED_XREFS, [undefined_function_calls, undefined_functions,
locals_not_used, exports_not_used,
deprecated_function_calls, deprecated_functions]).
%% ===================================================================
%% Public API
%% ===================================================================
-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
init(State) ->
Provider = providers:create([{name, ?PROVIDER},
{module, ?MODULE},
{deps, ?DEPS},
{bare, true},
{example, "rebar3 xref"},
{short_desc, short_desc()},
{desc, desc()}]),
State1 = rebar_state:add_provider(State, Provider),
{ok, State1}.
-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
do(State) ->
rebar_paths:set_paths([runtime], State),
XrefChecks = prepare(State),
XrefIgnores = rebar_state:get(State, xref_ignores, []),
%% Run xref checks
?INFO("Running cross reference analysis...", []),
XrefResults = xref_checks(XrefChecks, XrefIgnores),
%% Run custom queries
QueryChecks = rebar_state:get(State, xref_queries, []),
QueryResults = lists:foldl(fun check_query/2, [], QueryChecks),
stopped = xref:stop(xref),
case XrefResults =:= [] andalso QueryResults =:= [] of
true ->
{ok, State};
false ->
?PRV_ERROR({xref_issues, XrefResults, QueryResults})
end.
-spec format_error(any()) -> iolist().
format_error({xref_issues, XrefResults, QueryResults}) ->
lists:flatten(display_results(XrefResults, QueryResults));
format_error(Reason) ->
io_lib:format("~p", [Reason]).
%% ===================================================================
%% Internal functions
%% ===================================================================
short_desc() ->
"Run cross reference analysis.".
desc() ->
io_lib:format(
"~ts~n"
"~n"
"Valid rebar.config options:~n"
" ~p~n"
" ~p~n"
" ~p~n"
" ~p~n",
[short_desc(),
{xref_warnings, false},
{xref_extra_paths,[]},
{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\"))",[]}]}
]).
-spec prepare(rebar_state:t()) -> [atom()].
prepare(State) ->
{ok, _} = xref:start(xref),
ok = xref:set_library_path(xref, code_path(State)),
xref:set_default(xref, [{warnings,
rebar_state:get(State, xref_warnings, false)},
{verbose, rebar_log:is_verbose(State)}]),
[{ok, _} = xref:add_directory(xref, Dir)
|| App <- rebar_state:project_apps(State),
%% the directory may not exist in rare cases of a compile
%% hook of a dep running xref prior to the full job being done
Dir <- [rebar_app_info:ebin_dir(App)], filelib:is_dir(Dir)],
%% Get list of xref checks we want to run
ConfXrefChecks = rebar_state:get(State, xref_checks,
[exports_not_used,
undefined_function_calls]),
XrefChecks = sets:to_list(sets:intersection(
sets:from_list(?SUPPORTED_XREFS),
sets:from_list(ConfXrefChecks))),
XrefChecks.
xref_checks(XrefChecks, XrefIgnores) ->
run_xref_checks(XrefChecks, XrefIgnores, []).
run_xref_checks([], _XrefIgnores, Acc) ->
Acc;
run_xref_checks([XrefCheck | T], XrefIgnores, Acc) ->
{ok, Results} = xref:analyze(xref, XrefCheck),
case filter_xref_results(XrefCheck, XrefIgnores, Results) of
[] ->
run_xref_checks(T, XrefIgnores, Acc);
FilterResult ->
run_xref_checks(T, XrefIgnores, [{XrefCheck, FilterResult} | Acc])
end.
check_query({Query, Value}, Acc) ->
{ok, Answer} = xref:q(xref, Query),
case Answer =:= Value of
false ->
[{Query, Value, Answer} | Acc];
_ ->
Acc
end.
code_path(State) ->
[P || P <- code:get_path() ++
rebar_state:get(State, xref_extra_paths, []),
filelib:is_dir(P)].
%% Ignore behaviour functions, and explicitly marked functions
%%
%% Functions can be ignored by using
%% -ignore_xref([{F, A}, {M, F, A}...]).
get_xref_ignorelist(Mod, XrefCheck) ->
%% Get ignore_xref attribute and combine them in one list
Attributes =
try
Mod:module_info(attributes)
catch
_Class:_Error -> []
end,
IgnoreXref = keyall(ignore_xref, Attributes),
BehaviourCallbacks = get_behaviour_callbacks(XrefCheck, Attributes),
%% And create a flat {M,F,A} list
lists:foldl(
fun({F, A}, Acc) -> [{Mod,F,A} | Acc];
({M, F, A}, Acc) -> [{M,F,A} | Acc];
(M, Acc) when is_atom(M) -> [M | Acc]
end, [], lists:flatten([IgnoreXref, BehaviourCallbacks])).
keyall(Key, List) ->
lists:flatmap(fun({K, L}) when Key =:= K -> L; (_) -> [] end, List).
get_behaviour_callbacks(exports_not_used, Attributes) ->
lists:map(fun(Mod) ->
try
Mod:behaviour_info(callbacks)
catch
error:undef ->
?WARN("Behaviour ~p is used but cannot be found.", [Mod]),
[]
end
end, keyall(behaviour, Attributes) ++ keyall(behavior, Attributes));
get_behaviour_callbacks(_XrefCheck, _Attributes) ->
[].
filter_xref_results(XrefCheck, XrefIgnores, XrefResults) ->
SearchModules = lists:usort(
lists:map(
fun({Mt,_Ft,_At}) -> Mt;
({{Ms,_Fs,_As},{_Mt,_Ft,_At}}) -> Ms;
(_) -> undefined
end, XrefResults)),
Ignores = XrefIgnores ++ lists:flatmap(fun(Module) ->
get_xref_ignorelist(Module, XrefCheck)
end, SearchModules),
lists:filter( fun(Result) -> pred_xref_result(Result, Ignores) end, XrefResults).
pred_xref_result({Src, Dest}, Ignores) -> pred_xref_result1(Src, Ignores)
andalso pred_xref_result1(Dest, Ignores);
pred_xref_result(Vertex, Ignores) -> pred_xref_result1(Vertex, Ignores).
pred_xref_result1(Vertex, Ignores) ->
Mod = case Vertex of {Module, _Func, _Arity} -> Module;
_ -> Vertex end,
not lists:member(Vertex, Ignores) andalso not lists:member(Mod, Ignores).
display_results(XrefResults, QueryResults) ->
[lists:map(fun display_xref_results_for_type/1, XrefResults),
lists:map(fun display_query_result/1, QueryResults)].
display_query_result({Query, Answer, Value}) ->
io_lib:format("Query ~ts~n answer ~p~n did not match ~p~n",
[Query, Answer, Value]).
display_xref_results_for_type({Type, XrefResults}) ->
lists:map(display_xref_result_fun(Type), XrefResults).
display_xref_result_fun(Type) ->
fun(XrefResult) ->
{Source, SMFA, TMFA} =
case XrefResult of
{MFASource, MFATarget} ->
{format_mfa_source(MFASource),
format_mfa(MFASource),
format_mfa(MFATarget)};
MFATarget ->
{format_mfa_source(MFATarget),
format_mfa(MFATarget),
undefined}
end,
case Type of
undefined_function_calls ->
io_lib:format("~tsWarning: ~ts calls undefined function ~ts (Xref)\n",
[Source, SMFA, TMFA]);
undefined_functions ->
io_lib:format("~tsWarning: ~ts is undefined function (Xref)\n",
[Source, SMFA]);
locals_not_used ->
io_lib:format("~tsWarning: ~ts is unused local function (Xref)\n",
[Source, SMFA]);
exports_not_used ->
io_lib:format("~tsWarning: ~ts is unused export (Xref)\n",
[Source, SMFA]);
deprecated_function_calls ->
io_lib:format("~tsWarning: ~ts calls deprecated function ~ts (Xref)\n",
[Source, SMFA, TMFA]);
deprecated_functions ->
io_lib:format("~tsWarning: ~ts is deprecated function (Xref)\n",
[Source, SMFA]);
Other ->
io_lib:format("~tsWarning: ~ts - ~ts xref check: ~ts (Xref)\n",
[Source, SMFA, TMFA, Other])
end
end.
format_mfa({M, F, A}) ->
?FMT("~ts:~ts/~w", [M, F, A]).
format_mfa_source(MFA) ->
case find_mfa_source(MFA) of
{module_not_found, function_not_found} -> "";
{Source, function_not_found} -> ?FMT("~ts: ", [Source]);
{Source, Line} -> ?FMT("~ts:~w: ", [Source, Line])
end.
%%
%% Extract an element from a tuple, or undefined if N > tuple size
%%
safe_element(N, Tuple) ->
try
element(N, Tuple)
catch
error:badarg ->
undefined
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
%% being too paranoid here.
%%
find_mfa_source({M, F, A}) ->
case code:get_object_code(M) of
error -> {module_not_found, function_not_found};
{M, Bin, _} -> find_function_source(M,F,A,Bin)
end.
find_function_source(M, F, A, Bin) ->
ChunksLookup = beam_lib:chunks(Bin, [abstract_code]),
{ok, {M, [{abstract_code, AbstractCodeLookup}]}} = ChunksLookup,
case AbstractCodeLookup of
no_abstract_code ->
% There isn't much else we can do at this point
{module_not_found, function_not_found};
{raw_abstract_v1, AbstractCode} ->
find_function_source_in_abstract_code(F, A, AbstractCode)
end.
find_function_source_in_abstract_code(F, A, AbstractCode) ->
%% Extract the original source filename from the abstract code
[{attribute, _, file, {Source0, _}} | _] = [Attr || Attr = {attribute, _, file, _} <- AbstractCode],
Source = rebar_dir:make_relative_path(Source0, rebar_dir:get_cwd()),
%% Extract the line number for a given function def
Fn = [E || E <- AbstractCode,
safe_element(1, E) == function,
safe_element(3, E) == F,
safe_element(4, E) == A],
case Fn of
[{function, Anno, F, _, _}] -> {Source, erl_anno:line(Anno)};
%% do not crash if functions are exported, even though they
%% are not in the source.
%% parameterized modules add new/1 and instance/1 for example.
[] -> {Source, function_not_found}
end.