Fix crash with sigils inside ignore

For some reason the sigil_suffix token might be missing text property.

Fixes #363

Author: michalmuskala

src/erlfmt_scan.erl

@@ -235,7 +235,17 @@ drop_initial_white_space(Rest) ->
 
 -spec stringify_tokens([erl_scan:token()]) -> string().
 stringify_tokens(Tokens) ->
-    lists:flatmap(fun erl_scan:text/1, Tokens).
+    lists:flatmap(fun token_text/1, Tokens).
+
+-spec token_text(erl_scan:token()) -> string().
+token_text(Token) ->
+    case erl_scan:text(Token) of
+        %% sigil_suffix might miss the text field
+        undefined when is_record(Token, sigil_suffix, 3) ->
+            "";
+        Text ->
+            Text
+    end.
 
 -spec split_tokens([erl_scan:token()], [erl_scan:token()]) ->
     {[token()], [erl_scan:token()], [comment()], [token()]}.

test/erlfmt_SUITE.erl

@@ -100,6 +100,7 @@
     snapshot_range_reinjected/1,
     snapshot_tripple_string/1,
     snapshot_tripple_crash/1,
+    snapshot_sigil_crash/1,
     contains_pragma/1,
     insert_pragma/1,
     overlong_warning/1,
@@ -184,7 +185,8 @@ groups() ->
         ]},
         {otp_27_snapshot_tests, [parallel], [
             snapshot_tripple_string,
-            snapshot_tripple_crash
+            snapshot_tripple_crash,
+            snapshot_sigil_crash
         ]},
         {error_tests, [parallel], [
             error_ignore_begin_ignore,
@@ -1115,6 +1117,8 @@ snapshot_tripple_string(Config) -> snapshot_formatted("tripple_string.erl", Conf
 
 snapshot_tripple_crash(Config) -> snapshot_same("tripple_crash.erl", Config).
 
+snapshot_sigil_crash(Config) -> snapshot_same("sigil_crash.erl", Config).
+
 snapshot_same(Module, Config) ->
     Pragma = proplists:get_value(pragma, Config, ignore),
     snapshot_match(Module, Module, Config, [{pragma, Pragma}]).

test/erlfmt_SUITE_data/sigil_crash.erl

@@ -0,0 +1,10 @@
+-module(sigil).
+-export([f/0]).
+% erlfmt:ignore
+f() -> ~"foo", ~"foo"a.
+
+% erlfmt:ignore
+f() -> ~B"foo", ~B"foo"a.
+
+%erlfmt:ignore
+f() -> ~|foo|, ~|foo|a.