[Tcl-bugs] [ tcl-Bugs-231259 ] shadowing byte-compiled commands

[<no...@so...>]

Bugs item #231259, was updated on 2001-02-06 06:43
You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=110894&aid=231259&group_id=10894

Category: [namespace]
>Group: 8.4a3
Status: Open
Resolution: None
Priority: 3
Submitted By: miguel sofer (msofer)
Assigned to: miguel sofer (msofer)
>Summary: shadowing byte-compiled commands

Initial Comment:
According to the comments for the function TclResetShadowedCmdRefs in generic/tclNamesp.c the following should not happen:

   % #define a namespace proc that uses the global command 'set'
   % namespace eval mig {proc test {} {set ::g 0}}; mig::test
   0
  %  
  % #define a namespace proc 'set' that shadows the global command; 
  % #the previously compiled 'test' never notices!
  % namespace eval mig {proc set {a b} {::set a [incr b]}}; mig::test   0
  % #>>>>>>>>>>>
  % #? Shouldn't the namespace epoch have been bumped up by the 
  % #shadowing, ? so that all procs are recompiled?
  % #>>>>>>>>>>>
  %
  % #if I redefine, and hence force recompilation of 'test', it is ok.)   
  % namespace eval mig {proc test {} {set ::g 0}}; mig::test
   1
  

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Comment By: miguel sofer (msofer)
Date: 2001-05-10 13:50

Message:
Logged In: YES 
user_id=148712

Sorry about that "second example"; it is only an example of
how stupid one gets when doing things in haste ...

No bug in that situation if programmed correctly: the
redefinition of 'mySet' should have a body 
    {uplevel set $var [expr $val + 1]}
and then things work out as they should ...

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Comment By: miguel sofer (msofer)
Date: 2001-05-10 12:14

Message:
Logged In: YES 
user_id=148712

A different aspect of the same bug is shown by the example:

% namespace export set
    namespace eval mig {
        namespace import ::set
        rename set mySet

        proc test {a} {
            variable var
            mySet var $a
        }

        test 0
        set var0 $var

        rename mySet {}
        proc mySet {var val} {
            set $var [expr $val + 1]
        }

        test 0
        set var1 $var

        puts "$var0 $var1"
    }
% 0 0


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Comment By: miguel sofer (msofer)
Date: 2001-02-07 13:16

Message:
No, I'm not ... 

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Comment By: miguel sofer (msofer)
Date: 2001-02-07 12:25

Message:
I am submitting a patch to tclProc.c that fixes this. 

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Comment By: miguel sofer (msofer)
Date: 2001-02-07 10:35

Message:
It seems to be a deeper bug; some global commands (eg, set) are compiled directly to bytecode. Commands that shadow *them* are immune to the implementation of the 'reset on shadowing': it invalidates command *references* in the bytecode, but there is no command reference to 'set' in there!
Maybe shadowing should force recompilation of the proc, and not just a fresh resolution of command names? In that case, a small patch to TclProcCompileProc (generic/tclProc.c) would arrange it.

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Comment By: miguel sofer (msofer)
Date: 2001-02-06 08:06

Message:
Sorry for the title, it is way too specific and maybe misleading! A correct title would be 
* Incorrect command scoping *

I do not actually know if, in the example above, cmdRefEpoch was not updated, or if it was but the bytecompiler ignored it.

msofer

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http://sourceforge.net/tracker/?func=detail&atid=110894&aid=231259&group_id=10894