Added support to verify reverse dependencies in a transaction.

See https://plus.google.com/106812073015308749022/posts/ZXMHimd8iKd

NEWS

@@ -1,5 +1,10 @@
 xbps-0.25 (???):
 
+ * Added support to validate reverse dependencies when updating packages.
+   Such example would be updating pkg X to 2.0 when an installed package
+   depends on pkg X < 2.0; abort transaction when such condition is
+   detected; this also works with virtual packages.
+
  * Dropped requirement of confuse when using the libxbps API.
 
  * Dropped support for external libfetch and proplib; the included copies

bin/xbps-install/transaction.c

@@ -51,10 +51,9 @@ show_missing_deps(xbps_array_t a)
 	unsigned int i;
 	const char *str;
 
-	fprintf(stderr, "Unable to locate some required packages:\n");
 	for (i = 0; i < xbps_array_count(a); i++) {
 		xbps_array_get_cstring_nocopy(a, i, &str);
-		fprintf(stderr, " %s\n", str);
+		fprintf(stderr, "%s\n", str);
 	}
 }
 
@@ -64,10 +63,9 @@ show_conflicts(xbps_array_t a)
 	unsigned int i;
 	const char *str;
 
-	fprintf(stderr, "Conflicting packages were found:\n");
 	for (i = 0; i < xbps_array_count(a); i++) {
 		xbps_array_get_cstring_nocopy(a, i, &str);
-		fprintf(stderr, " %s\n", str);
+		fprintf(stderr, "%s\n", str);
 	}
 }
 
@@ -272,11 +270,13 @@ exec_transaction(struct xbps_handle *xhp, int maxcols, bool yes, bool drun)
 			    xbps_dictionary_get(xhp->transd, "missing_deps");
 			/* missing packages */
 			show_missing_deps(mdeps);
+			fprintf(stderr, "Transaction aborted due to missing/conflicting packages.\n");
 			goto out;
 		} else if (rv == EAGAIN) {
 			/* conflicts */
 			cflicts = xbps_dictionary_get(xhp->transd, "conflicts");
 			show_conflicts(cflicts);
+			fprintf(stderr, "Transaction aborted due to missing/conflicting packages.\n");
 			goto out;
 		}
 		xbps_dbg_printf(xhp, "Empty transaction dictionary: %s\n",
@@ -324,6 +324,5 @@ out:
 		xbps_object_iterator_release(trans->iter);
 	if (trans)
 		free(trans);
-
 	return rv;
 }

include/xbps_api_impl.h

@@ -176,6 +176,12 @@ xbps_dictionary_t HIDDEN xbps_find_pkg_in_dict(xbps_dictionary_t, const char *);
 xbps_dictionary_t HIDDEN xbps_find_virtualpkg_in_dict(struct xbps_handle *,
 					xbps_dictionary_t,
 					const char *);
+/**
+ * @private
+ * From lib/transaction_revdeps.c
+ */
+void HIDDEN xbps_transaction_revdeps(struct xbps_handle *);
+
 /**
  * @private
  * From lib/transaction_sortdeps.c

lib/Makefile

@@ -38,6 +38,7 @@ OBJS += package_remove.o package_find_obsoletes.o package_state.o
 OBJS += package_unpack.o package_register.o package_script.o
 OBJS += transaction_commit.o transaction_package_replace.o
 OBJS += transaction_dictionary.o transaction_sortdeps.o transaction_ops.o
+OBJS += transaction_revdeps.o
 OBJS += download.o initend.o pkgdb.o package_conflicts.o
 OBJS += plist.o plist_find.o plist_match.o archive.o
 OBJS += plist_remove.o plist_fetch.o util.o util_hash.o 

lib/package_conflicts.c

@@ -75,7 +75,7 @@ xbps_pkg_find_conflicts(struct xbps_handle *xhp,
 			xbps_dbg_printf(xhp, "found conflicting installed "
 			    "pkg %s with pkg in transaction %s\n", pkgver,
 			    repopkgver);
-			buf = xbps_xasprintf("%s conflicts with "
+			buf = xbps_xasprintf("CONFLICT: %s with "
 			    "installed pkg %s", repopkgver, pkgver);
 			xbps_array_add_cstring(trans_cflicts, buf);
 			free(buf);
@@ -97,7 +97,7 @@ xbps_pkg_find_conflicts(struct xbps_handle *xhp,
 			free(pkgname);
 			xbps_dbg_printf(xhp, "found conflicting pkgs in "
 			    "transaction %s <-> %s\n", pkgver, repopkgver);
-			buf = xbps_xasprintf("%s conflicts with "
+			buf = xbps_xasprintf("CONFLICT: %s with "
 			   "%s in transaction", repopkgver, pkgver);
 			xbps_array_add_cstring(trans_cflicts, buf);
 			free(buf);

lib/repo_pkgdeps.c

@@ -135,9 +135,12 @@ out:
 		xbps_object_iterator_release(iter);
 	if (update_pkgdep)
 		xbps_array_remove(mdeps, idx);
-	if (add_pkgdep && !xbps_add_obj_to_array(mdeps, reqpkg_str)) {
+	if (add_pkgdep) {
-		xbps_object_release(reqpkg_str);
+		char *str;
-		return errno;
+
+		str = xbps_xasprintf("MISSING: %s", reqpkg_str);
+		xbps_array_add_cstring(mdeps, str);
+		free(str);
 	}
 
 	return rv;

lib/transaction_dictionary.c

@@ -244,17 +244,18 @@ xbps_transaction_prepare(struct xbps_handle *xhp)
 		return ENXIO;
 
 	/*
-	 * If there are missing deps bail out.
+	 * If there are missing deps or revdeps bail out.
 	 */
+	xbps_transaction_revdeps(xhp);
 	mdeps = xbps_dictionary_get(xhp->transd, "missing_deps");
-	if (xbps_array_count(mdeps) > 0)
+	if (xbps_array_count(mdeps))
 		return ENODEV;
 
 	/*
 	 * If there are package conflicts bail out.
 	 */
 	conflicts = xbps_dictionary_get(xhp->transd, "conflicts");
-	if (xbps_array_count(conflicts) > 0)
+	if (xbps_array_count(conflicts))
 		return EAGAIN;
 
 	/*

lib/transaction_revdeps.c

@@ -0,0 +1,176 @@
+/*-
+ * Copyright (c) 2013 Juan Romero Pardines.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <errno.h>
+
+#include "xbps_api_impl.h"
+
+/*
+ * Verify reverse dependencies for packages in transaction.
+ * This will catch cases where a package update would break its reverse dependencies:
+ *
+ * 	- foo-1.0 is being updated to 2.0.
+ * 	- baz-1.1 depends on foo<2.0.
+ * 	- foo is updated to 2.0, hence baz-1.1 is currently broken.
+ *
+ * Abort transaction if such case is found.
+ */
+static bool
+check_virtual_pkgs(struct xbps_handle *xhp,
+		   xbps_dictionary_t trans_pkgd,
+		   xbps_dictionary_t rev_pkgd)
+{
+	xbps_array_t provides, rundeps, mdeps;
+	const char *pkgver, *revpkgver, *pkgpattern;
+	char *pkgname, *vpkgname, *vpkgver, *str;
+	unsigned int i, x;
+	bool matched = false;
+
+	provides = xbps_dictionary_get(trans_pkgd, "provides");
+	for (i = 0; i < xbps_array_count(provides); i++) {
+		char *tmp = NULL;
+
+		xbps_array_get_cstring(provides, i, &vpkgver);
+		if (strchr(vpkgver, '_') == NULL) {
+			tmp = xbps_xasprintf("%s_1", vpkgver);
+			vpkgver = strdup(tmp);
+		}
+		vpkgname = xbps_pkg_name(vpkgver);
+		assert(vpkgname);
+		rundeps = xbps_dictionary_get(rev_pkgd, "run_depends");
+		for (x = 0; x < xbps_array_count(rundeps); x++) {
+			xbps_array_get_cstring_nocopy(rundeps, x, &pkgpattern);
+			if (((pkgname = xbps_pkgpattern_name(pkgpattern)) == NULL) &&
+			    ((pkgname = xbps_pkg_name(pkgpattern)) == NULL))
+				continue;
+
+			if (strcmp(vpkgname, pkgname)) {
+				free(pkgname);
+				continue;
+			}
+			free(pkgname);
+			if (xbps_pkgpattern_match(vpkgver, pkgpattern))
+				continue;
+
+			mdeps = xbps_dictionary_get(xhp->transd, "missing_deps");
+			xbps_dictionary_get_cstring_nocopy(trans_pkgd, "pkgver", &pkgver);
+			xbps_dictionary_get_cstring_nocopy(rev_pkgd, "pkgver", &revpkgver);
+			str = xbps_xasprintf("CONFLICT: `%s' update "
+			    "breaks `%s', needs `%s' virtual pkg (got `%s`)",
+			    pkgver, revpkgver, pkgpattern, vpkgver);
+			xbps_array_add_cstring(mdeps, str);
+			free(str);
+			matched = true;
+		}
+		free(vpkgver);
+	}
+	return matched;
+}
+
+void HIDDEN
+xbps_transaction_revdeps(struct xbps_handle *xhp)
+{
+	xbps_array_t mdeps, unsorted, pkgrdeps, rundeps;
+	xbps_dictionary_t revpkgd;
+	xbps_object_t obj;
+	const char *pkgver, *revpkgver, *curpkgver, *tract;
+	char *pkgname, *str;
+	unsigned int i, x;
+
+	unsorted = xbps_dictionary_get(xhp->transd, "unsorted_deps");
+
+	for (i = 0; i < xbps_array_count(unsorted); i++) {
+		obj = xbps_array_get(unsorted, i);
+		/*
+		 * Only check packages in transaction being updated.
+		 */
+		xbps_dictionary_get_cstring_nocopy(obj, "transaction", &tract);
+		if (strcmp(tract, "update"))
+			continue;
+		/*
+		 * if pkg in transaction is not installed,
+		 * pass to next one.
+		 */
+		xbps_dictionary_get_cstring_nocopy(obj, "pkgver", &pkgver);
+		pkgname = xbps_pkg_name(pkgver);
+		assert(pkgname);
+		if (xbps_pkg_is_installed(xhp, pkgname) == 0) {
+			free(pkgname);
+			continue;
+		}
+		/*
+		 * If pkg is installed but does not have revdeps,
+		 * pass to next one.
+		 */
+		pkgrdeps = xbps_pkgdb_get_pkg_revdeps(xhp, pkgname);
+		if (!xbps_array_count(pkgrdeps)) {
+			free(pkgname);
+			continue;
+		}
+		free(pkgname);
+		/*
+		 * Time to validate revdeps for current pkg.
+		 */
+		for (x = 0; x < xbps_array_count(pkgrdeps); x++) {
+			xbps_array_get_cstring_nocopy(pkgrdeps, x, &curpkgver);
+			revpkgd = xbps_pkgdb_get_pkg(xhp, curpkgver);
+			/*
+			 * First try to match any supported virtual package.
+			 */
+			if (check_virtual_pkgs(xhp, obj, revpkgd))
+				continue;
+			/*
+			 * Try to match real dependencies.
+			 */
+			rundeps = xbps_dictionary_get(revpkgd, "run_depends");
+			if (xbps_match_pkgdep_in_array(rundeps, pkgver))
+				continue;
+			/*
+			 * Installed package conflicts with package
+			 * in transaction being updated, check
+			 * if a new version of this conflicting package
+			 * is in the transaction.
+			 */
+			pkgname = xbps_pkg_name(curpkgver);
+			if (xbps_find_pkg_in_array(unsorted, pkgname)) {
+				free(pkgname);
+				continue;
+			}
+			free(pkgname);
+			mdeps = xbps_dictionary_get(xhp->transd, "missing_deps");
+			xbps_dictionary_get_cstring_nocopy(revpkgd,
+			    "pkgver", &revpkgver);
+			str = xbps_xasprintf("CONFLICT: `%s' "
+			    "update breaks `%s', needs `%s'",
+			    pkgver, revpkgver, curpkgver);
+			xbps_array_add_cstring(mdeps, str);
+			free(str);
+		}
+
+	}
+}