Firebird 6.0.0 is eating underscores in character set when running external execute statements

[tonne1]

Requirements:
2 FB6 databases with character set ISO8859_1. Lets call them "caller" and "target".

1. In one of them (caller), create this SP:

create or alter procedure check_external (
    un varchar(100),
    pw varchar(100),
    dbc varchar(100) )
returns (
    cdate varchar(100) )
as
declare sql varchar(1000);
begin
  -- get creation date of external db
  sql = 'select mon$creation_date from mon$database';
  execute statement :sql as user :un password :pw on external :dbc into :cdate;
  suspend;
end;

2. Make sure the other database (target) is not connected.
3. Fill in placeholders to access target and query its creation date by running this from caller:

select * from check_external('<username>', '<password>', '<host/port:alias>');

result:

335544325 : bad parameters on attach or create database
335544509 : CHARACTER SET "SYSTEM"."ISO88591" is not defined
Data source : Firebird::<host/port:alias>; 
At procedure "PUBLIC"."CHECK_EXTERNAL" line: 15, col: 3 
[SQLState:42000, ISC error code:335544921]

Notice character set "ISO88591" in the error msg, it should be "ISO8859_1" of course.

BUT: If target is already connected from somewhere else, the statement runs fine.

[aafemt]

ISO88591 is default alias for ISO8859_1 so it is not because someone eat underscore, just another name resolution failure.

[tonne1]

From a user perspective, the bug renders ESOE unusable in databases with character sets which have underscores.

[mrotteveel]

ISO88591 is default alias for ISO8859_1 so it is not because someone eat underscore, just another name resolution failure.

It probably is because the underscore is eaten, which then surfaces a second bug, with the name resolution.

[asfernandes]

The actual bug is not with EXECUTE STATEMENT. This is just consequence of another bug.

This is not accepted anymore:

isql dbfdb -ch iso88591

Looks like character set alias query was removed from connection character set lookup.

Looks like regression of metadata cache.

EXECUTE STATEMENT sends the "name" of the current connection charset. This name is a name defined inside the intl implementation and in this case is ISO88591.