[Tcl-bugs] [ tcl-Bugs-983509 ] Tcl_RegisterConfig ignores encoding failure

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Bugs item #983509, was opened at 2004-07-01 12:05
Message generated for change (Comment added) made by dgp
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Category: 52. Config Reporting
Group: development: 8.5a2
Status: Open
Resolution: None
Priority: 5
Submitted By: Don Porter (dgp)
Assigned to: Andreas Kupries (andreas_kupries)
Summary: Tcl_RegisterConfig ignores encoding failure

Initial Comment:

Tcl_RegisterConfig() receives a "valEncoding"
argument that specifies the encoding for
the string values in the "configuration" table
of values.  Those values are copied into
a dictionary, converting to UTF-encoding.

Problem arises when
Tcl_GetEncoding(NULL, valEncoding)
returns NULL -- essentially meaning the
appropriate *.enc file for that encoding could
not be found.

In that circumstance, T_RC ignores the
encoding failure, and goes ahead an
converts the config values according
to whatever Tcl thinks the system encoding
is at the moment.  

Since T_GE() failed, we know this cannot
be the right thing -- we are definitely converting
based on the wrong encoding -- and worse, we
can't even predict what wrong thing T_RC
will do instead.

When the "valEncoding" cannot be found,
no data should be copied over to the
dictionary, since it cannot be done correctly.
Whether [pkgconfig] should also not be defined,
or whether it should be defined with no data,
I'm not sure.





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>Comment By: Don Porter (dgp)
Date: 2004-07-16 17:35

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I don't know whether an 8.5-based
Tclkit is something that exists.

If it did, it could avoid this problem
by making sure the valEncoding
value is "utf-8".

If valEncoding were something like
"iso8859-1", though, then using that
encoding requires finding the iso8859-1.enc
file while requires mounting the VFS in
which that file is found, which requires
a [package require] of the tclvfs package, 
which requires creating an interp, which
includes a call to Tcl_RegisterConfig.

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Comment By: Andreas Kupries (andreas_kupries)
Date: 2004-07-16 17:22

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In other words, an 8.5-based Tclkit is currently always
using the wrong encoding for the embedded values ?

More pressure on us to understand and untangle the startup,
encoding, fs, etc, right ?


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Comment By: Don Porter (dgp)
Date: 2004-07-16 17:19

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If we take that approach, though,
I expect a Tclkit built on Tcl 8.5
to always panic at startup.

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Comment By: Andreas Kupries (andreas_kupries)
Date: 2004-07-16 15:25

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We could also 'panic'. This might actually best, because
something is so seriously wrong that we cannot fix the
situaiton, IMHO.

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