Tcl Source Code

In Tcl built with <code>-DPURIFY</code> and <code>--enable-symbols</code>, the
following script results in a segmentation fault:

<code><verbatim>
variable res {}
namespace eval ns1 {
    namespace export *
    proc p1 {} {
        return success
    }
    interp alias {} [namespace current]::p2 {} [namespace current]::p1
}


namespace eval ns2 {
    namespace import [namespace parent]::ns1::p2
}

proc ondelete {oldname newname op} {
    variable res
    catch {
        $oldname
    } cres
    set res [string match {invalid command name*ns1::p1*} $cres]
}
trace add command  ns2::p2 delete ondelete
namespace delete ns1
</verbatim></code>

The issue is that the delete trace on the imported routine deletes the
namespace of the underlying routine, resulting in the deletion of both the
underlying routine and the alias, but then the imported command is called, and
its <code>ImportedCmdData</code> structure still holds a reference to the
now-deleted Alias structure.

This fix was committed to core-8-branch in [037c0ff27fd5d0a2] and also made its
way to trunk via merge of core-8-branch.  [3b0e92b198b86975] is unrelated and
shouldn't have been noted in this report.

@pooryorick: Noting that commit [3b0e92b198b86975] was on core-8-branch, is this bug now fixed on all branches?

This - indeed - looks OK now, but it's only applied to 8.6 yet. Will 8.7 and 9.0 follow soon? Then it can be closed.

Fixed again in [3b0e92b198b86975].

Re-opening, because this fix broke the build: [https://github.com/tcltk/tcl/actions/runs/852459210]

Fix applied to core-8-6-branch in [e45d054ba46ee5c2].

Fixed in [037c0ff27fd5d0a2] by modifying
<code>Tcl_DeleteCommandFromToken()</code> so that it deletes any imports of the
routine before deleting the routine itself.