[Tcl-bugs] [ tcl-Bugs-3608360 ] Incompatible behaviour of "file exists"

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Bugs item #3608360, was opened at 2013-03-18 01:28
Message generated for change (Comment added) made by nijtmans
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Category: 16. Commands A-H
Group: current: 8.6.0
>Status: Pending
>Resolution: Invalid
Priority: 8
Private: No
Submitted By: Uwe Schmitz (schmitzu)
Assigned to: Jan Nijtmans (nijtmans)
Summary: Incompatible behaviour of "file exists"

Initial Comment:
There is an incompatibilty concerning "file exists"
in 8.6:

% puts $tcl_patchLevel
8.6.0
% glob *
x.tcl
% file exists *.tcl
1

Whereas in 8.5:
% puts $tcl_patchLevel
8.5.12
% glob *
x.tcl
% file exists *.tcl
0

platform: Win7_x64,
tcl-binaries: ActiveState.

This breaks backward compatibility.

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>Comment By: Jan Nijtmans (nijtmans)
Date: 2013-03-18 06:03

Message:
On UNIX (actually Cygwin):
$ tclsh8.5
% puts $tcl_patchLevel
8.5.13
% glob *.tcl
x.tcl
% file exists *.tcl
0

$ tclsh8.6
% puts $tcl_patchLevel
8.6.0
% glob *.tcl
x.tcl
% file exists *.tcl
0
% exit


Conclusion: the fact that using the '*' character this way
in [file exists] worked at all in win32 was an undocumented
feature and is non-portable. On UNIX, the '*' character can be
used in filenames like any other character, only it must be
escaped if the filename goes through a shell.

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Comment By: Jan Nijtmans (nijtmans)
Date: 2013-03-18 03:55

Message:
I will have a look. Thanks!

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Comment By: Donal K. Fellows (dkf)
Date: 2013-03-18 02:59

Message:
Definitely a problem in implementation of NativeAccess() in tclWinFile.c
(the generic layers over that do the right thing) but I really don't know
the relevant API. Is this related to 2893771?  (Committed on 2009-11-24 in
https://core.tcl.tk/tcl/info/02224b9ef68c so it fits with being an 8.6.*
issue.) We're feeding a filename into FindFirstFile which is the directory
entry enumerator, which in turn is the only thing that can do that sort of
thing with a glob patter AIUI. My knowledge of the deep ins-and-outs of
Win32 is too small for me to go further.

Assigning to someone who knows more about the relevant bits than me.
Perhaps just testing for glob metacharacters in the name would be enough? I
vaguely remember them as being always forbidden in filenames...

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