edoc, syntax_tools: Don't fail on invalid UTF-8

As a temporary measure to ease the transition to default UTF-8
encoding, automatically fall back to the Latin-1 encoding (without any
warnings; the Erlang Compiler will emit a proper warning).

The intention is to remove this workaround in OTP 18 or 19.

1 files changed, 12 insertions, 1 deletions

diff --git a/lib/syntax_tools/src/erl_comment_scan.erl b/lib/syntax_tools/src/erl_comment_scan.erl
index dae7530ce7..03429d4d42 100644
--- a/lib/syntax_tools/src/erl_comment_scan.erl
+++ b/lib/syntax_tools/src/erl_comment_scan.erl
@@ -72,13 +72,24 @@ file(Name) ->
 	{ok, V} ->
 	    case V of
 		{ok, B} ->
-                    Enc = case epp:read_encoding(Name) of
+                    Encoding = epp:read_encoding_from_binary(B),
+                    Enc = case Encoding of
                               none -> epp:default_encoding();
                               Enc0 -> Enc0
                           end,
                     case catch unicode:characters_to_list(B, Enc) of
                         String when is_list(String) ->
                             string(String);
+                        R when Encoding =:= none ->
+                            case
+                              catch unicode:characters_to_list(B, latin1)
+                            of
+                                String when is_list(String) ->
+                                    string(String);
+                                _ ->
+                                    error_read_file(Name1),
+                                    exit(R)
+                            end;
                         R ->
                             error_read_file(Name1),
                             exit(R)