libalpm/add.c,trans.c : cleanup of requiredby handling.

This patch cleans up and fix the _alpm_trans_update_depends function
and ensure that all requiredby fields are filled in case of multiple satisfiers
(previously, the handling of mutliple satisfiers in that function was inconsistent).

This makes a special case handling of requiredby in commit_single_pkg() obsolete,
and so allows cleaning that code as well.

Also fixed upgrade056 pactest because :
1) the requiredby fields were wrong, and this wouldn't happen with the fixed _alpm_trans_update_depends().
2) this is a very unusual case anyway (and handling all corner cases combined to a broken database
  seems nearly impossible to achieve).

References :
http://www.archlinux.org/pipermail/pacman-dev/2007-July/008919.html
http://www.archlinux.org/pipermail/pacman-dev/2007-July/008920.html

Signed-off-by: Chantry Xavier <shiningxc@gmail.com>

4 files changed, 16 insertions, 98 deletions

diff --git a/lib/libalpm/add.c b/lib/libalpm/add.c
index 9ef83d91..398839a6 100644
--- a/lib/libalpm/add.c
+++ b/lib/libalpm/add.c
@@ -827,43 +827,6 @@ static int commit_single_pkg(pmpkg_t *newpkg, int pkg_current, int pkg_count,
 	 * looking for packages depending on the package to add */
 	_alpm_pkg_update_requiredby(newpkg);
 
-	/* special case: if our provides list has changed from oldpkg to newpkg AND
-	 * we get here, we need to make sure we find the actual provision that
-	 * still satisfies this case, and update its 'requiredby' field... ugh */
-	/* TODO this seems really messy and should be taken care of elsewhere */
-	alpm_list_t *provdiff, *prov;
-	provdiff = alpm_list_diff(alpm_pkg_get_provides(oldpkg),
-			alpm_pkg_get_provides(newpkg),
-			_alpm_str_cmp);
-	for(prov = provdiff; prov; prov = prov->next) {
-		const char *provname = prov->data;
-		_alpm_log(PM_LOG_DEBUG, "provision '%s' has been removed from package %s (%s => %s)",
-				provname, alpm_pkg_get_name(oldpkg),
-				alpm_pkg_get_version(oldpkg), alpm_pkg_get_version(newpkg));
-
-		alpm_list_t *p = _alpm_db_whatprovides(handle->db_local, provname);
-		if(p) {
-			/* we now have all the provisions in the local DB for this virtual
-			 * package... seeing as we can't really determine which is the 'correct'
-			 * provision, we'll use the FIRST for now.
-			 * TODO figure out a way to find a "correct" provision */
-			pmpkg_t *provpkg = p->data;
-			const char *pkgname = alpm_pkg_get_name(provpkg);
-			_alpm_log(PM_LOG_DEBUG, "updating '%s' due to provision change (%s)",
-					pkgname, provname);
-			_alpm_pkg_update_requiredby(provpkg);
-
-			if(_alpm_db_write(db, provpkg, INFRQ_DEPENDS)) {
-				_alpm_log(PM_LOG_ERROR, _("could not update provision '%s' from '%s'"),
-						provname, pkgname);
-				alpm_logaction("error: could not update provision '%s' from '%s'",
-						provname, pkgname);
-				RET_ERR(PM_ERR_DB_WRITE, -1);
-			}
-		}
-	}
-	alpm_list_free(provdiff);
-
 	/* make an install date (in UTC) */
 	time_t t = time(NULL);
 	strncpy(newpkg->installdate, asctime(gmtime(&t)), PKG_DATE_LEN);
diff --git a/lib/libalpm/package.c b/lib/libalpm/package.c
index e11d7476..135a3510 100644
--- a/lib/libalpm/package.c
+++ b/lib/libalpm/package.c
@@ -1109,6 +1109,9 @@ int _alpm_pkg_splitname(const char *target, char *name, char *version, int witha
 
 /* scan the local db to fill in requiredby field of package,
  * used when we want to install or add a package */
+
+/* A depends on B through n depends <=> A listed in B's requiredby n times
+ * n == 0 or 1 in almost all cases */
 void _alpm_pkg_update_requiredby(pmpkg_t *pkg)
 {
 	const alpm_list_t *i, *j;
diff --git a/lib/libalpm/trans.c b/lib/libalpm/trans.c
index ca8d6ce9..8c35fa36 100644
--- a/lib/libalpm/trans.c
+++ b/lib/libalpm/trans.c
@@ -428,6 +428,8 @@ int _alpm_trans_commit(pmtrans_t *trans, alpm_list_t **data)
 	return(0);
 }
 
+/* A depends on B through n depends <=> A listed in B's requiredby n times
+ * n == 0 or 1 in almost all cases */
 int _alpm_trans_update_depends(pmtrans_t *trans, pmpkg_t *pkg)
 {
 	alpm_list_t *i, *j;
@@ -436,7 +438,7 @@ int _alpm_trans_update_depends(pmtrans_t *trans, pmpkg_t *pkg)
 	pmdb_t *localdb;
 
 	ALPM_LOG_FUNC;
-		
+
 	/* Sanity checks */
 	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));
 	ASSERT(pkg != NULL, RET_ERR(PM_ERR_PKG_INVALID, -1));
@@ -453,40 +455,22 @@ int _alpm_trans_update_depends(pmtrans_t *trans, pmpkg_t *pkg)
 
 	localdb = alpm_option_get_localdb();
 	for(i = depends; i; i = i->next) {
+		if(!i->data) {
+			continue;
+		}
 		pmdepend_t* dep = alpm_splitdep(i->data);
 		if(dep == NULL) {
 			continue;
 		}
-	
-		if(trans->packages && trans->type == PM_TRANS_TYPE_REMOVE) {
-			if(_alpm_pkg_find(dep->name, handle->trans->packages)) {
-				continue;
-			}
-		}
-
-		pmpkg_t *deppkg = _alpm_db_get_pkgfromcache(localdb, dep->name);
-		if(!deppkg) {
-			int found_provides = 0;
-			/* look for a provides package */
-			alpm_list_t *provides = _alpm_db_whatprovides(localdb, dep->name);
-			for(j = provides; j; j = j->next) {
-				if(!j->data) {
-					continue;
-				}
-				pmpkg_t *provpkg = j->data;
-				deppkg = _alpm_db_get_pkgfromcache(localdb, alpm_pkg_get_name(provpkg));
-
-				if(!deppkg) {
-					continue;
-				}
-
-				found_provides = 1;
-
+		for(j = _alpm_db_get_pkgcache(localdb); j; j = j->next) {
+			pmpkg_t *deppkg = j->data;
+			if(deppkg && alpm_depcmp(deppkg, dep)) {
 				/* this is cheating... we call this function to populate the package */
 				alpm_list_t *rqdby = alpm_pkg_get_requiredby(deppkg);
 
 				_alpm_log(PM_LOG_DEBUG, "updating 'requiredby' field for package '%s'",
 				          alpm_pkg_get_name(deppkg));
+
 				if(trans->type == PM_TRANS_TYPE_REMOVE
 						|| trans->type == PM_TRANS_TYPE_REMOVEUPGRADE) {
 					void *data = NULL;
@@ -494,11 +478,8 @@ int _alpm_trans_update_depends(pmtrans_t *trans, pmpkg_t *pkg)
 					FREE(data);
 					deppkg->requiredby = rqdby;
 				} else {
-					/* sanity check to make sure package was not already in list */
-					if(!alpm_list_find_str(rqdby, pkgname)) {
-						rqdby = alpm_list_add(rqdby, strdup(pkgname));
-						deppkg->requiredby = rqdby;
-					}
+					rqdby = alpm_list_add(rqdby, strdup(pkgname));
+					deppkg->requiredby = rqdby;
 				}
 
 				if(_alpm_db_write(localdb, deppkg, INFRQ_DEPENDS)) {
@@ -506,36 +487,6 @@ int _alpm_trans_update_depends(pmtrans_t *trans, pmpkg_t *pkg)
 										alpm_pkg_get_name(deppkg), alpm_pkg_get_version(deppkg));
 				}
 			}
-			alpm_list_free(provides);
-
-			if(!found_provides) {
-				_alpm_log(PM_LOG_DEBUG, "could not find dependency '%s'", dep->name);
-				continue;
-			}
-		}
-
-		/* this is cheating... we call this function to populate the package */
-		alpm_list_t *rqdby = alpm_pkg_get_requiredby(deppkg);
-
-		_alpm_log(PM_LOG_DEBUG, "updating 'requiredby' field for package '%s'",
-		          alpm_pkg_get_name(deppkg));
-		if(trans->type == PM_TRANS_TYPE_REMOVE
-						|| trans->type == PM_TRANS_TYPE_REMOVEUPGRADE) {
-			void *data = NULL;
-			rqdby = alpm_list_remove(rqdby, pkgname, _alpm_str_cmp, &data);
-			FREE(data);
-			deppkg->requiredby = rqdby;
-		} else {
-			/* sanity check to make sure package was not already in list */
-			if(!alpm_list_find_str(rqdby, pkgname)) {
-				rqdby = alpm_list_add(rqdby, strdup(pkgname));
-				deppkg->requiredby = rqdby;
-			}
-		}
-
-		if(_alpm_db_write(localdb, deppkg, INFRQ_DEPENDS)) {
-			_alpm_log(PM_LOG_ERROR, _("could not update 'requiredby' database entry %s-%s"),
-					alpm_pkg_get_name(deppkg), alpm_pkg_get_version(deppkg));
 		}
 		free(dep);
 	}
diff --git a/pactest/tests/upgrade056.py b/pactest/tests/upgrade056.py
index 8419731c..b92c38ac 100644
--- a/pactest/tests/upgrade056.py
+++ b/pactest/tests/upgrade056.py
@@ -11,6 +11,7 @@ self.addpkg2db("local", lp2)
 
 lp3 = pmpkg("pkg3")
 lp3.provides = ["imaginary"]
+lp3.requiredby = [ "pkg1" ]
 self.addpkg2db("local", lp3)
 
 p = pmpkg("pkg2", "1.0-2")