Fix els_parser crash due to erlfmt returning {skip, _}

Erlfmt will skip parsing if it finds pragma @noformat in the text.
In order to trick erlfmt to parse the file we @noformat with @doformat

apps/els_lsp/src/els_parser.erl

@@ -35,18 +35,32 @@ parse(Text) ->
     case erlfmt:read_nodes_string("nofile", String) of
         {ok, Forms, _ErrorInfo} ->
             {ok, lists:flatten(parse_forms(Forms))};
+        {skip, _} ->
+            ?LOG_INFO("Erlfmt skipped parsing, try to fix it."),
+            parse(fix_erlfmt(Text));
         {error, _ErrorInfo} ->
             {ok, []}
     end.
 
+-spec fix_erlfmt(binary()) -> binary().
+fix_erlfmt(Text) ->
+    %% erlfmt will skip if it finds pragma @noformat, so we remove it
+    binary:replace(Text, <<"@noformat">>, <<"@doformat">>).
+
 -spec parse_file(file:name_all()) -> {ok, [tree()]} | {error, term()}.
 parse_file(FileName) ->
     forms_to_ast(erlfmt:read_nodes(FileName)).
 
 -spec parse_text(binary()) -> {ok, [tree()]} | {error, term()}.
 parse_text(Text) ->
     String = els_utils:to_list(Text),
-    forms_to_ast(erlfmt:read_nodes_string("nofile", String)).
+    case erlfmt:read_nodes_string("nofile", String) of
+        {skip, _} ->
+            ?LOG_INFO("Erlfmt skipped parsing, try to fix it."),
+            parse_text(fix_erlfmt(Text));
+        Result ->
+            forms_to_ast(Result)
+    end.
 
 -spec forms_to_ast(tuple()) -> {ok, [tree()]} | {error, term()}.
 forms_to_ast({ok, Forms, _ErrorInfo}) ->

apps/els_lsp/test/els_parser_SUITE.erl

@@ -34,7 +34,8 @@
     var_in_application/1,
     unicode_clause_pattern/1,
     latin1_source_code/1,
-    record_comment/1
+    record_comment/1,
+    pragma_noformat/1
 ]).
 
 %%==============================================================================
@@ -472,6 +473,15 @@ record_comment(_Config) ->
     ),
     ok.
 
+%% Issue #1482
+%% Erlfmt returns {skip, _} if the text contains pragma @noformat.
+%% This would cause els_parser to crash.
+-spec pragma_noformat(config()) -> ok.
+pragma_noformat(_Config) ->
+    Text = <<"%% @noformat\nfoo">>,
+    ?assertMatch({ok, _}, els_parser:parse(Text)),
+    ?assertMatch({ok, _}, els_parser:parse_text(Text)).
+
 %%==============================================================================
 %% Helper functions
 %%==============================================================================