Tcl Source Code

What platform is this (though I doubt that would make a difference). I could not reproduce this in 9.0.0, 9.0.2, 9.0.3 and trunk (9.1) on Windows.

% info pat
9.0.3
% lseq 0 count 5
0 1 2 3 4
% lseq count 5
invalid bareword "count"
in expression "count";
should be "$count" or "{count}" or "count(...)" or ...
% lseq 0 count 5
0 1 2 3 4

Ok, found the difference. I have history turned off in my tclshrc. Re-enabling it reproduces the error.

It also means (I suspect) the error would not occur in a script (including the test suite!) since history is disabled in that situation.

In any case, I confirm that it's a real bug that needs investigating.

Thank you for this report!

Even without the unexpected interaction with the user's environment, the use of lseq key words in positions of numeric arguments, should be checked by the command, and provide a more meaningful error message.

And in fact, the error can be reproduced in a script as well. The argument just has to have a reference count > 1.

x.tcl:

set count count
puts [catch {lseq 0 $count 5} result],$result
puts [catch {lseq $count 5} result],$result
puts [catch {lseq 0 $count 5} result],$result

Running it,

c:\src\tcltk\wip\tcl\win>tclsh x.tcl
0,0 1 2 3 4
1,invalid bareword "count"
in expression "count";
should be "$count" or "{count}" or "count(...)" or ...
1,invalid bareword "count"
in expression "count";
should be "$count" or "{count}" or "count(...)" or ...

I think the optimization in function SequenceIdentifyArgument is broken

	if (TclHasInternalRep(argPtr, &tclExprCodeType)) {
	   goto doExpr;
	}

Basing a decision on the current internal representation type feels like it violates EIAS. Here for example, "count" is an invalid expression but still has bytecode representing it generated (which will raise an error). "count" passed as the third argument though is not to be treated as an integer but a keyword. The above fragment means that treatment of "count" depends on what the last type it was shimmered to which feels like a violation of EIAS.