misc/146947: [ports] bsd.ports.mk incorrectly using pkg-deinstall for both deinstall and post-deinstall operations

[Garrett Cooper]

>Number:         146947
>Category:       misc
>Synopsis:       [ports] bsd.ports.mk incorrectly using pkg-deinstall for both deinstall and post-deinstall operations
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue May 25 06:50:01 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Garrett Cooper
>Release:        9-CURRENT
>Organization:
Cisco Systems, Inc.
>Environment:
FreeBSD bayonetta.local 9.0-CURRENT FreeBSD 9.0-CURRENT #0 r206173M: Mon Apr 26 22:45:06 PDT 2010     root at bayonetta.local:/usr/obj/usr/src/sys/BAYONETTA.ata  amd64
>Description:
pkg-deinstall as specified by the ports infrastructure is being incorrectly used as both the deinstall and post-deinstall script instead of just being the deinstall script.

Example:

$ sudo make deinstall
===>  Deinstalling for devel/py-ctypes
===>   Deinstalling py26-ctypes-1.0.2
cd: can't cd to /usr/local/lib/python%%PYVER%%/
pkg_delete: deinstall script returned error status
cd: can't cd to /usr/local/lib/python%%PYVER%%/
pkg_delete: post-deinstall script returned error status
$ cat pkg-deinstall
#!/bin/sh

PYVER='%%PYVER%%'

set -e

cd "$PKG_PREFIX/lib/python${PYVER}/"

find -s -X . -name '*.py[co]' | xargs rm -f
find -s -X . -type d | xargs rmdir -p

The error was unintentional, but the outcome was interesting nonetheless.

The actual problem appears to be pkg_install though (note the Note: clause):

     -k dscript
             Set dscript to be the de-install procedure for the package.  This
             can be any executable program (or shell script).  It will be
             invoked automatically when the package is later (if ever) de-
             installed.  It will be passed the package's name as the first
             argument.

             Note: if the -K option is not given, this script will serve as
             both the de-install and the post-deinstall script for the pack-
             age, differentiating between the functionality by passing the
             keywords DEINSTALL and POST-DEINSTALL respectively, along with
             the package's name.

This behavior doesn't make sense; the deinstall script should be executed once and only once as executing these scripts twice only serves to cause confusion in the overall execution flow.

I believe that the code causing this is appears to be in delete/perform.c (in particular the second conditional block):

    /*
     * Test whether to use the old method of passing tokens to deinstallation
     * scripts, and set appropriate variables..
     */

    if (fexists(POST_DEINSTALL_FNAME)) {
        new_m = 1;
        post_script = POST_DEINSTALL_FNAME;
        pre_arg = post_arg = "";
    } else if (fexists(DEINSTALL_FNAME)) {
        post_script = DEINSTALL_FNAME;
        pre_arg = "DEINSTALL";
        post_arg = "POST-DEINSTALL";
    } else {
        post_script = pre_arg = post_arg = NULL;
    }

Whether or not this behavior should be deprecated is one thing, but I find it to be incredibly confusing.
>How-To-Repeat:
1. Create a package with pkg_create -k foo, like the following script:

cat > foo <<EOF
#!/bin/sh
echo "my name is \${0##*/}"; false
EOF

2. Add the package.
3. Delete the package.

The output from package delete will be:

"my name is POST-INSTALL"
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: