There's one more part to this implementation, eliding
a -U into a -i if/when a -debuginfo upgrade is attempted.

But caveat emptor (and very lightly testedn so far). The goal for a  
different
upgrade policy with -debugfo packages is described here
     https://bugzilla.redhat.com/process_bug.cgi

Note that the mechanism of using the number of packages
that have an identifier attached, and undertaking some associated
action (like erasing -debuginfo in this case) is far more general
than automating -debuginfo erasures.

73 de Jeff

>   RPM Package Manager, CVS Repository
>   http://rpm5.org/cvs/
>    
> ______________________________________________________________________ 
> ______
>
>   Server: rpm5.org                         Name:   Jeff Johnson
>   Root:   /v/rpm/cvs                       Email:  jbj@rpm5.org
>   Module: rpm                              Date:   30-May-2008  
> 21:10:12
>   Branch: HEAD                             Handle: 2008053019101200
>
>   Modified files:
>     rpm                     CHANGES
>     rpm/lib                 depends.c
>
>   Log:
>     - jbj: add automagic erasures of -debuginfo packages (#447708).
>
>   Summary:
>     Revision    Changes     Path
>     1.2382      +1  -0      rpm/CHANGES
>     1.401       +106 -3     rpm/lib/depends.c
>    
> ______________________________________________________________________ 
> ______
>
>   patch -p0 <<'@@ .'
>   Index: rpm/CHANGES
>    
> ====================================================================== 
> ======
>   $ cvs diff -u -r1.2381 -r1.2382 CHANGES
>   --- rpm/CHANGES	30 May 2008 19:05:18 -0000	1.2381
>   +++ rpm/CHANGES	30 May 2008 19:10:12 -0000	1.2382
>   @@ -1,5 +1,6 @@
>
>    5.1.0 -> 5.2a0:
>   +    - jbj: add automagic erasures of -debuginfo packages (#447708).
>        - jbj: enable -lgcrypt through ./devtool system.
>        - jbj: hdrfmt: achieve coverage over new header format  
> extensions.
>        - jbj: rpmrepo: add baseurl to the repo markup.
>   @@ .
>   patch -p0 <<'@@ .'
>   Index: rpm/lib/depends.c
>    
> ====================================================================== 
> ======
>   $ cvs diff -u -r1.400 -r1.401 depends.c
>   --- rpm/lib/depends.c	23 May 2008 16:30:45 -0000	1.400
>   +++ rpm/lib/depends.c	30 May 2008 19:10:12 -0000	1.401
>   @@ -180,6 +180,8 @@
>    /*@unchecked@*/
>    static rpmTag _upgrade_tag;
>    /*@unchecked@*/
>   +static rpmTag _debuginfo_tag;
>   +/*@unchecked@*/
>    static rpmTag _obsolete_tag;
>
>    /**
>   @@ -201,7 +203,7 @@
>        int xx;
>
>        if (_upgrade_tag == 0) {
>   -	const char *t = rpmExpand("%{?_upgrade_tag}", NULL);
>   +	const char * t = rpmExpand("%{?_upgrade_tag}", NULL);
>    /*@-mods@*/
>    	_upgrade_tag = (!strcmp(t, "name") ? RPMTAG_NAME :  
> RPMTAG_PROVIDENAME);
>    /*@=mods@*/
>   @@ -266,6 +268,105 @@
>    }
>
>    /**
>   + * Check string for a suffix.
>   + * @param fn		string
>   + * @param suffix	suffix
>   + * @return		1 if string ends with suffix
>   + */
>   +static inline int chkSuffix(const char * fn, const char * suffix)
>   +        /*@*/
>   +{
>   +    size_t flen = strlen(fn);
>   +    size_t slen = strlen(suffix);
>   +    return (flen > slen && !strcmp(fn + flen - slen, suffix));
>   +}
>   +
>   +/**
>   + * Add unreferenced debuginfo erasures to a transaction set.
>   + * @param ts		transaction set
>   + * @param p		transaction element
>   + * @param h		header
>   + * @param pkgKey	added package key (erasure uses RPMAL_NOKEY)
>   + * @return		0 on success
>   + */
>   +static int rpmtsEraseDebuginfo(rpmts ts, rpmte p, Header h,  
> alKey pkgKey)
>   +{
>   +    HE_t he = memset(alloca(sizeof(*he)), 0, sizeof(*he));
>   +    const void *keyval = NULL;
>   +    size_t keylen = 0;
>   +    size_t nrefs = 0;
>   +    uint32_t debuginfoInstance = 0;
>   +    Header debuginfoHeader = NULL;
>   +    rpmdbMatchIterator mi;
>   +    Header oh;
>   +    int xx;
>   +
>   +    /* XXX SOURCEPKGID is not populated reliably, do not use  
> (yet). */
>   +    if (_debuginfo_tag == 0) {
>   +	const char * t = rpmExpand("%{?_debuginfo_tag}", NULL);
>   +/*@-mods@*/
>   +	_debuginfo_tag = (*t != '\0' && !strcmp(t, "pkgid")
>   +		? RPMTAG_SOURCEPKGID : RPMTAG_SOURCERPM);
>   +/*@=mods@*/
>   +	t = _free(t);
>   +    }
>   +
>   +    /* Grab the retrieval key. */
>   +    switch (_debuginfo_tag) {
>   +    default:		return 0;	/*@notreached@*/	break;
>   +    case RPMTAG_SOURCERPM:	keyval = rpmteSourcerpm(p);	break;
>   +    }
>   +
>   +    /* Count remaining members in build set, excluding - 
> debuginfo (if any). */
>   +    mi = rpmtsInitIterator(ts, _debuginfo_tag, keyval, keylen);
>   +    xx = rpmdbPruneIterator(mi, ts->removedPackages, ts- 
> >numRemovedPackages, 1);
>   +    while((oh = rpmdbNextIterator(mi)) != NULL) {
>   +	/* Skip identical packages. */
>   +	if (rpmHeadersIdentical(h, oh))
>   +	    continue;
>   +
>   +	he->tag = RPMTAG_NAME;
>   +	xx = headerGet(oh, he, 0);
>   +	if (!xx || he->p.str == NULL)
>   +	    continue;
>   +	/* Save the -debuginfo member. */
>   +	if (chkSuffix(he->p.str, "-debuginfo")) {
>   +	    debuginfoInstance = rpmdbGetIteratorOffset(mi);
>   +	    debuginfoHeader = headerLink(oh);
>   +	} else
>   +	    nrefs++;
>   +	he->p.str = _free(he->p.str);
>   +    }
>   +    mi = rpmdbFreeIterator(mi);
>   +
>   +    /* Remove -debuginfo package when last build member is  
> erased. */
>   +    if (nrefs == 0 && debuginfoInstance > 0 && debuginfoHeader ! 
> = NULL) {
>   +	int lastx = -1;
>   +	rpmte q;
>   +
>   +	/* Create an erasure element. */
>   +	lastx = -1;
>   +	xx = removePackage(ts, debuginfoHeader, debuginfoInstance,
>   +		&lastx, pkgKey);
>   +assert(lastx >= 0 && lastx < ts->orderCount);
>   +	q = ts->order[lastx];
>   +
>   +	/* Chain through upgrade flink. */
>   +	/* XXX avoid assertion failure when erasing. */
>   +	if (pkgKey != RPMAL_NOMATCH)
>   +	    xx = rpmteChain(p, q, oh, "Upgrades");
>   +
>   +/*@-nullptrarith@*/
>   +	rpmlog(RPMLOG_DEBUG, D_("   lastref erases %s\n"), rpmteNEVRA(q));
>   +/*@=nullptrarith@*/
>   +
>   +    }
>   +    debuginfoHeader = headerFree(debuginfoHeader);
>   +
>   +    return 0;
>   +}
>   +
>   +/**
>     * Add Obsoletes: erasures to a transaction set.
>     * @param ts		transaction set
>     * @param p		transaction element
>   @@ -587,6 +688,7 @@
>        /* Add upgrades to the transaction (if not disabled). */
>        if (!(depFlags & RPMDEPS_FLAG_NOUPGRADE)) {
>    	xx = rpmtsAddUpgrades(ts, p, hcolor, h);
>   +	xx = rpmtsEraseDebuginfo(ts, p, h, pkgKey);
>        }
>
>        /* Add Obsoletes: to the transaction (if not disabled). */
>   @@ -607,9 +709,10 @@
>    {
>        int oc = -1;
>        int rc = removePackage(ts, h, dboffset, &oc, RPMAL_NOMATCH);
>   -    if (rc == 0 && oc >= 0 && oc < ts->orderCount)
>   +    if (rc == 0 && oc >= 0 && oc < ts->orderCount) {
>   +	(void) rpmtsEraseDebuginfo(ts, ts->order[oc], h, RPMAL_NOMATCH);
>    	ts->teErase = ts->order[oc];
>   -    else
>   +    } else
>    	ts->teErase = NULL;
>        return rc;
>    }
>   @@ .
> ______________________________________________________________________
> RPM Package Manager                                    http://rpm5.org
> CVS Sources Repository                                rpm-cvs@rpm5.org