doc: Requires.private is used for header inclusion

Document that "pkgconf --cflags" inherits paths for including headers
from dependencies listed in Requires.private.

https://github.com/pkgconf/pkgconf/issues/300
https://github.com/pkgconf/pkgconf/issues/352

.gitignore

@@ -1,13 +1,19 @@
+Makefile
+Makefile.in
+.dirstamp
+stamp-h*
 *.h.in~
 *.o
 *.og
 *.op
+*.lo
 *.gcno
 *.gcda
 *.gcov
 core
 .gdb_history
 
+.libs
 .deps
 
 *.exe
@@ -16,8 +22,8 @@ core
 *.orig
 *.patch
 *.rej
-/tests/run.sh
 
+# autoconf stuff
 /aclocal.m4
 /autom4te.cache/
 /buildsys.mk
@@ -26,8 +32,47 @@ core
 /config.log
 /config.status
 /configure
+/compile
+/config.guess
+/config.sub
+/depcomp
+/install-sh
+/missing
+
+# programs
+/bomtool
 /pkgconf
 /pkgconf-gcov
 /pkgconf-profile
 
-Makefile
+# libtool
+/libtool
+/ltmain.sh
+/libpkgconf.la
+/m4/libtool.m4
+/m4/lt~obsolete.m4
+/m4/ltoptions.m4
+/m4/ltsugar.m4
+/m4/ltversion.m4
+
+# pkgconfig file
+/libpkgconf.pc
+
+# autoheader
+/libpkgconf/config.h
+/libpkgconf/config.h.in
+
+# tests
+/Kyuafile
+/tests/Kyuafile
+/tests/basic
+/tests/builtins
+/tests/conflicts
+/tests/framework
+/tests/parser
+/tests/provides
+/tests/regress
+/tests/requires
+/tests/sysroot
+/tests/test_env.sh
+/tests/version

Makefile.am

@@ -159,7 +159,7 @@ libpkgconf_la_SOURCES  =	\
 		libpkgconf/path.c		\
 		libpkgconf/personality.c	\
 		libpkgconf/parser.c
-libpkgconf_la_LDFLAGS = -no-undefined -version-info 4:0:0 -export-symbols-regex '^pkgconf_'
+libpkgconf_la_LDFLAGS = -no-undefined -version-info 5:0:0 -export-symbols-regex '^pkgconf_'
 
 dist_man_MANS    = 		\
 	man/pkgconf.1		\

Makefile.lite

@@ -39,7 +39,7 @@ all: pkgconf-lite
 libpkgconf/config.h:
 	@echo '#define PACKAGE_NAME "pkgconf-lite"' >> $@
 	@echo '#define PACKAGE_BUGREPORT "https://git.dereferenced.org/pkgconf/pkgconf/issues"' >> $@
-	@echo '#define PACKAGE_VERSION "2.1.0"' >> $@
+	@echo '#define PACKAGE_VERSION "2.2.0"' >> $@
 	@echo '#define PACKAGE PACKAGE_NAME " " PACKAGE_VERSION' >> $@
 	@echo '#define HAVE_STRLCPY' >> $@
 	@echo '#define HAVE_STRLCAT' >> $@

NEWS

@@ -1,6 +1,40 @@
 Changes from previous version of pkgconf
 ========================================
 
+Changes from 2.1.1 to 2.2.0:
+----------------------------
+
+* libpkgconf SOVERSION is now 5.
+
+* Significant solver rework to flatten both requires and requires.private
+  dependencies in a single pass.  Improves performance slightly and ensures
+  proper dependency order.
+  Patches by Kai Pastor.
+
+* Improve `--digraph` output to reflect more of the solver's state in the
+  rendered dependency graph.
+  Patches by Kai Pastor.
+
+* Do not reference the graph root by name when presenting error messages about
+  directly requested dependency nodes.
+  Patch by Kai Pastor.
+
+Changes from 2.1.0 to 2.1.1:
+----------------------------
+
+* Documentation fixes from Sam James and Stefan Weil.
+
+* Fix --modversion with constraints.
+  Patch by Kai Pastor.
+
+* Reintroduce an optimization to the dependency graph walker which avoids
+  revisiting already visited nodes.
+  Patch by Yi Chou with some modifications.
+
+* Add a regression test to check that the dependency flattener is working
+  as expected.
+  Patch by Kai Pastor.
+
 Changes from 2.0.3 to 2.1.0:
 ----------------------------
 
@@ -9,7 +43,7 @@ Changes from 2.0.3 to 2.1.0:
   Patches by Kai Pastor.
 
 * Fix warnings with GCC 14 -Walloc-size.
-  Patch by Sam Jones.
+  Patch by Sam James.
 
 * Add --solution to the pkgconf CLI to dump the solver state.
 

README.md

@@ -50,7 +50,7 @@ As previously mentioned, pkgconf makes optimizations to the linker flags in both
 case of static and shared linking in order to avoid overlinking binaries and also
 simplifies the `CFLAGS` and `LIBS` output of the pkgconf tool for improved readability.
 
-This functionality depends on the pkg-config module properly declaring it's dependency
+This functionality depends on the pkg-config module properly declaring its dependency
 tree instead of using `Libs` and `Cflags` fields to directly link against other modules
 which have pkg-config metadata files installed.
 
@@ -116,7 +116,7 @@ flags like so:
 
 
 pkgconf is compiled using [Meson](https://mesonbuild.com) on Windows. In theory, you could also use
-Meson to build on UNIX, but this is not recommended at this time as it pkgconf is typically built
+Meson to build on UNIX, but this is not recommended at this time as pkgconf is typically built
 much earlier than Meson.
 
     $ meson setup build -Dtests=disabled

cli/main.c

@@ -254,39 +254,71 @@ apply_provides(pkgconf_client_t *client, pkgconf_pkg_t *world, void *unused, int
 
 #ifndef PKGCONF_LITE
 static void
-print_digraph_node(pkgconf_client_t *client, pkgconf_pkg_t *pkg, void *unused)
+print_digraph_node(pkgconf_client_t *client, pkgconf_pkg_t *pkg, void *data)
 {
 	pkgconf_node_t *node;
 	(void) client;
-	(void) unused;
+	pkgconf_pkg_t **last_seen = data;
 
-	printf("\"%s\" [fontname=Sans fontsize=8]\n", pkg->id);
+	if(pkg->flags & PKGCONF_PKG_PROPF_VIRTUAL)
+		return;
+
+	if (pkg->flags & PKGCONF_PKG_PROPF_VISITED_PRIVATE)
+		printf("\"%s\" [fontname=Sans fontsize=8 fontcolor=gray color=gray]\n", pkg->id);
+	else
+		printf("\"%s\" [fontname=Sans fontsize=8]\n", pkg->id);
+
+	if (last_seen != NULL)
+	{
+		if (*last_seen != NULL)
+			printf("\"%s\" -> \"%s\" [fontname=Sans fontsize=8 color=red]\n", (*last_seen)->id, pkg->id);
+
+		*last_seen = pkg;
+	}
 
 	PKGCONF_FOREACH_LIST_ENTRY(pkg->required.head, node)
 	{
 		pkgconf_dependency_t *dep = node->data;
+		const char *dep_id = (dep->match != NULL) ? dep->match->id : dep->package;
 
-		printf("\"%s\" -> \"%s\" [fontname=Sans fontsize=8]\n", pkg->id, dep->package);
+		if ((dep->flags & PKGCONF_PKG_DEPF_PRIVATE) == 0)
+			printf("\"%s\" -> \"%s\" [fontname=Sans fontsize=8]\n", pkg->id, dep_id);
+		else
+			printf("\"%s\" -> \"%s\" [fontname=Sans fontsize=8 color=gray]\n", pkg->id, dep_id);
 	}
 
 	PKGCONF_FOREACH_LIST_ENTRY(pkg->requires_private.head, node)
 	{
 		pkgconf_dependency_t *dep = node->data;
+		const char *dep_id = (dep->match != NULL) ? dep->match->id : dep->package;
 
-		printf("\"%s\" -> \"%s\" [fontname=Sans fontsize=8 color=gray]\n", pkg->id, dep->package);
+		printf("\"%s\" -> \"%s\" [fontname=Sans fontsize=8 color=gray]\n", pkg->id, dep_id);
 	}
 }
 
 static bool
-apply_digraph(pkgconf_client_t *client, pkgconf_pkg_t *world, void *unused, int maxdepth)
+apply_digraph(pkgconf_client_t *client, pkgconf_pkg_t *world, void *data, int maxdepth)
 {
 	int eflag;
+	pkgconf_list_t *list = data;
+	pkgconf_pkg_t *last_seen = NULL;
+	pkgconf_node_t *iter;
 
 	printf("digraph deptree {\n");
 	printf("edge [color=blue len=7.5 fontname=Sans fontsize=8]\n");
 	printf("node [fontname=Sans fontsize=8]\n");
+	printf("\"user:request\" [fontname=Sans fontsize=8]\n");
 
-	eflag = pkgconf_pkg_traverse(client, world, print_digraph_node, unused, maxdepth, 0);
+	PKGCONF_FOREACH_LIST_ENTRY(list->head, iter)
+	{
+		pkgconf_queue_t *pkgq = iter->data;
+		pkgconf_pkg_t *pkg = pkgconf_pkg_find(client, pkgq->package);
+		printf("\"user:request\" -> \"%s\" [fontname=Sans fontsize=8]\n", pkg == NULL ? pkgq->package : pkg->id);
+		if (pkg != NULL)
+			pkgconf_pkg_unref(client, pkg);
+	}
+
+	eflag = pkgconf_pkg_traverse(client, world, print_digraph_node, &last_seen, maxdepth, 0);
 
 	if (eflag != PKGCONF_PKG_ERRF_OK)
 		return false;
@@ -333,7 +365,12 @@ apply_modversion(pkgconf_client_t *client, pkgconf_pkg_t *world, void *data, int
 			pkgconf_dependency_t *dep = world_iter->data;
 			pkgconf_pkg_t *pkg = dep->match;
 
-			if (strcmp(pkg->why, queue_node->package))
+			const size_t name_len = strlen(pkg->why);
+			if (name_len > strlen(queue_node->package) ||
+			    strncmp(pkg->why, queue_node->package, name_len) ||
+			    (queue_node->package[name_len] != 0 &&
+			     !isspace(queue_node->package[name_len]) &&
+			     !PKGCONF_IS_OPERATOR_CHAR(queue_node->package[name_len])))
 				continue;
 
 			if (pkg->version != NULL) {
@@ -1400,6 +1437,15 @@ cleanup3:
 			pkgconf_queue_push(&pkgq, package);
 			pkg_optind++;
 		}
+		else if (argv[pkg_optind + 2] == NULL)
+		{
+			char packagebuf[PKGCONF_BUFSIZE];
+
+			snprintf(packagebuf, sizeof packagebuf, "%s %s", package, argv[pkg_optind + 1]);
+			pkg_optind += 2;
+
+			pkgconf_queue_push(&pkgq, packagebuf);
+		}
 		else
 		{
 			char packagebuf[PKGCONF_BUFSIZE];
@@ -1468,7 +1514,7 @@ cleanup3:
 	if ((want_flags & PKG_DIGRAPH) == PKG_DIGRAPH)
 	{
 		want_flags &= ~(PKG_CFLAGS|PKG_LIBS);
-		apply_digraph(&pkg_client, &world, NULL, 2);
+		apply_digraph(&pkg_client, &world, &pkgq, 2);
 	}
 
 	if ((want_flags & PKG_SOLUTION) == PKG_SOLUTION)
@@ -1530,20 +1576,8 @@ cleanup3:
 			printf(" ");
 
 		if (!(want_flags & PKG_STATIC))
-		{
 			pkgconf_client_set_flags(&pkg_client, pkg_client.flags & ~PKGCONF_PKG_PKGF_SEARCH_PRIVATE);
 
-			/* redo the solution for the library set: free the solution itself, and any cached graph nodes */
-			pkgconf_solution_free(&pkg_client, &world);
-			pkgconf_cache_free(&pkg_client);
-
-			if (!pkgconf_queue_solve(&pkg_client, &pkgq, &world, maximum_traverse_depth))
-			{
-				ret = EXIT_FAILURE;
-				goto out;
-			}
-		}
-
 		apply_libs(&pkg_client, &world, NULL, 2);
 	}
 

configure.ac

@@ -12,7 +12,7 @@ dnl implied.  In no event shall the authors be liable for any damages arising
 dnl from the use of this software.
 
 AC_PREREQ([2.71])
-AC_INIT([pkgconf],[2.1.0],[https://github.com/pkgconf/pkgconf/issues/new])
+AC_INIT([pkgconf],[2.2.0],[https://github.com/pkgconf/pkgconf/issues/new])
 AC_CONFIG_SRCDIR([cli/main.c])
 AC_CONFIG_MACRO_DIR([m4])
 AX_CHECK_COMPILE_FLAG([-Wall], [CFLAGS="$CFLAGS -Wall"])

doc/libpkgconf-dependency.rst

@@ -51,7 +51,7 @@ The `dependency` module provides support for building `dependency lists` (the ba
 
 .. c:function:: void pkgconf_dependency_free(pkgconf_list_t *list)
 
-   Release a dependency list and it's child dependency nodes.
+   Release a dependency list and its child dependency nodes.
 
    :param pkgconf_list_t* list: The dependency list to release.
    :return: nothing

libpkgconf/dependency.c

@@ -262,7 +262,7 @@ pkgconf_dependency_unref(pkgconf_client_t *client, pkgconf_dependency_t *dep)
  *
  * .. c:function:: void pkgconf_dependency_free(pkgconf_list_t *list)
  *
- *    Release a dependency list and it's child dependency nodes.
+ *    Release a dependency list and its child dependency nodes.
  *
  *    :param pkgconf_list_t* list: The dependency list to release.
  *    :return: nothing

libpkgconf/libpkgconf.h

@@ -81,8 +81,8 @@ typedef struct pkgconf_queue_ pkgconf_queue_t;
 #define PKGCONF_FOREACH_LIST_ENTRY_REVERSE(tail, value) \
 	for ((value) = (tail); (value) != NULL; (value) = (value)->prev)
 
-#define LIBPKGCONF_VERSION	20003
-#define LIBPKGCONF_VERSION_STR	"2.0.3"
+#define LIBPKGCONF_VERSION	20200
+#define LIBPKGCONF_VERSION_STR	"2.2.0"
 
 struct pkgconf_queue_ {
 	pkgconf_node_t iter;
@@ -137,6 +137,8 @@ struct pkgconf_path_ {
 #define PKGCONF_PKG_PROPF_CACHED		0x02
 #define PKGCONF_PKG_PROPF_UNINSTALLED		0x08
 #define PKGCONF_PKG_PROPF_VIRTUAL		0x10
+#define PKGCONF_PKG_PROPF_ANCESTOR		0x20
+#define PKGCONF_PKG_PROPF_VISITED_PRIVATE	0x40
 
 struct pkgconf_pkg_ {
 	int refcount;
@@ -278,7 +280,6 @@ PKGCONF_API void pkgconf_cross_personality_deinit(pkgconf_cross_personality_t *p
 #define PKGCONF_PKG_PKGF_DONT_MERGE_SPECIAL_FRAGMENTS	0x4000
 #define PKGCONF_PKG_PKGF_FDO_SYSROOT_RULES		0x8000
 #define PKGCONF_PKG_PKGF_PKGCONF1_SYSROOT_RULES         0x10000
-#define PKGCONF_PKG_PKGF_ANCESTOR                       0x20000
 
 #define PKGCONF_PKG_DEPF_INTERNAL		0x1
 #define PKGCONF_PKG_DEPF_PRIVATE		0x2

libpkgconf/pkg.c

@@ -775,15 +775,13 @@ pkgconf_pkg_find(pkgconf_client_t *client, const char *name)
 	{
 		if ((f = fopen(name, "r")) != NULL)
 		{
-			pkgconf_pkg_t *pkg;
-
 			PKGCONF_TRACE(client, "%s is a file", name);
 
 			pkg = pkgconf_pkg_new_from_file(client, name, f, 0);
 			if (pkg != NULL)
 			{
 				pkgconf_path_add(pkg->pc_filedir, &client->dir_list, true);
-				return pkg;
+				goto out;
 			}
 		}
 	}
@@ -1456,7 +1454,11 @@ pkgconf_pkg_report_graph_error(pkgconf_client_t *client, pkgconf_pkg_t *parent,
 			client->already_sent_notice = true;
 		}
 
-		pkgconf_error(client, "Package '%s', required by '%s', not found\n", node->package, parent->id);
+		if (parent->flags & PKGCONF_PKG_PROPF_VIRTUAL)
+			pkgconf_error(client, "Package '%s' not found\n", node->package);
+		else
+			pkgconf_error(client, "Package '%s', required by '%s', not found\n", node->package, parent->id);
+
 		pkgconf_audit_log(client, "%s NOT-FOUND\n", node->package);
 	}
 	else if (eflags & PKGCONF_PKG_ERRF_PACKAGE_VER_MISMATCH)
@@ -1487,7 +1489,7 @@ pkgconf_pkg_walk_list(pkgconf_client_t *client,
 	unsigned int eflags = PKGCONF_PKG_ERRF_OK;
 	pkgconf_node_t *node, *next;
 
-	parent->flags |= PKGCONF_PKG_PKGF_ANCESTOR;
+	parent->flags |= PKGCONF_PKG_PROPF_ANCESTOR;
 
 	PKGCONF_FOREACH_LIST_ENTRY_SAFE(deplist->head, next, node)
 	{
@@ -1509,10 +1511,8 @@ pkgconf_pkg_walk_list(pkgconf_client_t *client,
 		if (pkgdep == NULL)
 			continue;
 
-		if((pkgdep->flags & PKGCONF_PKG_PKGF_ANCESTOR) != 0)
+		if((pkgdep->flags & PKGCONF_PKG_PROPF_ANCESTOR) != 0)
 		{
-			pkgdep->identifier = ++client->identifier;
-
 			/* In this case we have a circular reference.
 			 * We break that by deleteing the circular node from the
 			 * the list, so that we dont create a situation where
@@ -1540,14 +1540,12 @@ pkgconf_pkg_walk_list(pkgconf_client_t *client,
 
 		pkgconf_audit_log_dependency(client, pkgdep, depnode);
 
-		pkgdep->identifier = ++client->identifier;
-		pkgdep->serial = client->serial;
 		eflags |= pkgconf_pkg_traverse_main(client, pkgdep, func, data, depth - 1, skip_flags);
 next:
 		pkgconf_pkg_unref(client, pkgdep);
 	}
 
-	parent->flags &= ~PKGCONF_PKG_PKGF_ANCESTOR;
+	parent->flags &= ~PKGCONF_PKG_PROPF_ANCESTOR;
 
 	return eflags;
 }
@@ -1628,6 +1626,16 @@ pkgconf_pkg_traverse_main(pkgconf_client_t *client,
 	if (maxdepth == 0)
 		return eflags;
 
+	/* Short-circuit if we have already visited this node.
+	 */
+	if (root->serial == client->serial)
+		return eflags;
+
+	root->serial = client->serial;
+
+	if (root->identifier == 0)
+		root->identifier = ++client->identifier;
+
 	PKGCONF_TRACE(client, "%s: level %d, serial %"PRIu64, root->id, maxdepth, client->serial);
 
 	if ((root->flags & PKGCONF_PKG_PROPF_VIRTUAL) != PKGCONF_PKG_PROPF_VIRTUAL || (client->flags & PKGCONF_PKG_PKGF_SKIP_ROOT_VIRTUAL) != PKGCONF_PKG_PKGF_SKIP_ROOT_VIRTUAL)
@@ -1636,21 +1644,23 @@ pkgconf_pkg_traverse_main(pkgconf_client_t *client,
 			func(client, root, data);
 	}
 
-	if (!(client->flags & PKGCONF_PKG_PKGF_SKIP_CONFLICTS))
+	if (!(client->flags & PKGCONF_PKG_PKGF_SKIP_CONFLICTS) && root->conflicts.head != NULL)
 	{
+		PKGCONF_TRACE(client, "%s: walking 'Conflicts' list", root->id);
+
 		eflags = pkgconf_pkg_walk_conflicts_list(client, root, &root->conflicts);
 		if (eflags != PKGCONF_PKG_ERRF_OK)
 			return eflags;
 	}
 
-	PKGCONF_TRACE(client, "%s: walking requires list", root->id);
+	PKGCONF_TRACE(client, "%s: walking 'Requires' list", root->id);
 	eflags = pkgconf_pkg_walk_list(client, root, &root->required, func, data, maxdepth, skip_flags);
 	if (eflags != PKGCONF_PKG_ERRF_OK)
 		return eflags;
 
 	if (client->flags & PKGCONF_PKG_PKGF_SEARCH_PRIVATE)
 	{
-		PKGCONF_TRACE(client, "%s: walking requires.private list", root->id);
+		PKGCONF_TRACE(client, "%s: walking 'Requires.private' list", root->id);
 
 		/* XXX: ugly */
 		client->flags |= PKGCONF_PKG_PKGF_ITER_PKG_IS_PRIVATE;
@@ -1675,6 +1685,9 @@ pkgconf_pkg_traverse(pkgconf_client_t *client,
 	if (root->flags & PKGCONF_PKG_PROPF_VIRTUAL)
 		client->serial++;
 
+	if ((client->flags & PKGCONF_PKG_PKGF_SEARCH_PRIVATE) == 0)
+		skip_flags |= PKGCONF_PKG_DEPF_PRIVATE;
+
 	return pkgconf_pkg_traverse_main(client, root, func, data, maxdepth, skip_flags);
 }
 

libpkgconf/queue.c

@@ -103,134 +103,133 @@ pkgconf_queue_free(pkgconf_list_t *list)
 }
 
 static void
-pkgconf_queue_collect_dependents(pkgconf_client_t *client, pkgconf_pkg_t *pkg, void *data)
+pkgconf_queue_mark_public(pkgconf_client_t *client, pkgconf_pkg_t *pkg, void *data)
 {
+	if (pkg->flags & PKGCONF_PKG_PROPF_VISITED_PRIVATE)
+	{
+		pkgconf_list_t *list = data;
+		pkgconf_node_t *node;
+
+		PKGCONF_FOREACH_LIST_ENTRY(list->head, node)
+		{
+			pkgconf_dependency_t *dep = node->data;
+			if (dep->match == pkg)
+				dep->flags &= ~PKGCONF_PKG_DEPF_PRIVATE;
+		}
+
+		pkg->flags &= ~PKGCONF_PKG_PROPF_VISITED_PRIVATE;
+
+		PKGCONF_TRACE(client, "%s: updated, public", pkg->id);
+	}
+}
+
+static unsigned int
+pkgconf_queue_collect_dependencies_main(pkgconf_client_t *client,
+	pkgconf_pkg_t *root,
+	void *data,
+	int maxdepth);
+
+static inline unsigned int
+pkgconf_queue_collect_dependencies_walk(pkgconf_client_t *client,
+	pkgconf_list_t *deplist,
+	void *data,
+	int depth)
+{
+	unsigned int eflags = PKGCONF_PKG_ERRF_OK;
 	pkgconf_node_t *node;
 	pkgconf_pkg_t *world = data;
 
-	if (pkg == world)
-		return;
-
-	PKGCONF_FOREACH_LIST_ENTRY(pkg->required.head, node)
-	{
-		pkgconf_dependency_t *parent_dep = node->data;
-		pkgconf_dependency_t *flattened_dep;
-
-		flattened_dep = pkgconf_dependency_copy(client, parent_dep);
-
-		if ((client->flags & PKGCONF_PKG_PKGF_ITER_PKG_IS_PRIVATE) != PKGCONF_PKG_PKGF_ITER_PKG_IS_PRIVATE)
-			pkgconf_node_insert(&flattened_dep->iter, flattened_dep, &world->required);
-		else
-			pkgconf_node_insert(&flattened_dep->iter, flattened_dep, &world->requires_private);
-	}
-
-	if (client->flags & PKGCONF_PKG_PKGF_SEARCH_PRIVATE)
-	{
-		PKGCONF_FOREACH_LIST_ENTRY(pkg->requires_private.head, node)
-		{
-			pkgconf_dependency_t *parent_dep = node->data;
-			pkgconf_dependency_t *flattened_dep;
-
-			flattened_dep = pkgconf_dependency_copy(client, parent_dep);
-
-			pkgconf_node_insert(&flattened_dep->iter, flattened_dep, &world->requires_private);
-		}
-	}
-}
-
-static int
-dep_sort_cmp(const void *a, const void *b)
-{
-	const pkgconf_dependency_t *depA = *(void **) a;
-	const pkgconf_dependency_t *depB = *(void **) b;
-
-	return depB->match->identifier - depA->match->identifier;
-}
-
-static inline void
-flatten_dependency_set(pkgconf_client_t *client, pkgconf_list_t *list)
-{
-	pkgconf_node_t *node, *next;
-	pkgconf_dependency_t **deps = NULL;
-	size_t dep_count = 0, i;
-
-	PKGCONF_FOREACH_LIST_ENTRY_SAFE(list->head, next, node)
+	PKGCONF_FOREACH_LIST_ENTRY_REVERSE(deplist->tail, node)
 	{
 		pkgconf_dependency_t *dep = node->data;
-		pkgconf_pkg_t *pkg = pkgconf_pkg_verify_dependency(client, dep, NULL);
+		pkgconf_dependency_t *flattened_dep;
+		pkgconf_pkg_t *pkg = dep->match;
 
-		if (pkg == NULL)
+		if (*dep->package == '\0')
 			continue;
 
-		if (pkg->serial == client->serial)
-		{
-			pkgconf_node_delete(node, list);
-			pkgconf_dependency_unref(client, dep);
-			goto next;
-		}
-
-		if (dep->match == NULL)
+		if (pkg == NULL)
 		{
 			PKGCONF_TRACE(client, "WTF: unmatched dependency %p <%s>", dep, dep->package);
 			abort();
 		}
 
-		/* for virtuals, we need to check to see if there are dupes */
-		for (i = 0; i < dep_count; i++)
-		{
-			pkgconf_dependency_t *other_dep = deps[i];
-
-			PKGCONF_TRACE(client, "dedup %s = %s?", dep->package, other_dep->package);
-
-			if (!strcmp(dep->package, other_dep->package))
-			{
-				PKGCONF_TRACE(client, "skipping, "SIZE_FMT_SPECIFIER" deps", dep_count);
-				goto next;
-			}
-		}
-
-		pkg->serial = client->serial;
-
-		/* copy to the deps table */
-		dep_count++;
-		deps = pkgconf_reallocarray(deps, dep_count, sizeof (void *));
-		deps[dep_count - 1] = dep;
-
-		PKGCONF_TRACE(client, "added %s to dep table", dep->package);
-next:
-		pkgconf_pkg_unref(client, pkg);
-	}
-
-	if (deps == NULL)
-		return;
-
-	qsort(deps, dep_count, sizeof (void *), dep_sort_cmp);
-
-	/* zero the list and start readding */
-	pkgconf_list_zero(list);
-
-	for (i = 0; i < dep_count; i++)
-	{
-		pkgconf_dependency_t *dep = deps[i];
-
-		if (dep->match == NULL)
+		if (pkg->serial == client->serial)
 			continue;
 
-		memset(&dep->iter, '\0', sizeof (dep->iter));
-		pkgconf_node_insert(&dep->iter, dep, list);
+		if (client->flags & PKGCONF_PKG_PKGF_ITER_PKG_IS_PRIVATE)
+			pkg->flags |= PKGCONF_PKG_PROPF_VISITED_PRIVATE;
+		else
+			pkg->flags &= ~PKGCONF_PKG_PROPF_VISITED_PRIVATE;
 
-		PKGCONF_TRACE(client, "slot "SIZE_FMT_SPECIFIER": dep %s matched to %p<%s> id %"PRIu64, i, dep->package, dep->match, dep->match->id, dep->match->identifier);
+		eflags |= pkgconf_queue_collect_dependencies_main(client, pkg, data, depth - 1);
+
+		flattened_dep = pkgconf_dependency_copy(client, dep);
+		pkgconf_node_insert(&flattened_dep->iter, flattened_dep, &world->required);
 	}
 
-	free(deps);
+	return eflags;
+}
+
+static unsigned int
+pkgconf_queue_collect_dependencies_main(pkgconf_client_t *client,
+	pkgconf_pkg_t *root,
+	void *data,
+	int maxdepth)
+{
+	unsigned int eflags = PKGCONF_PKG_ERRF_OK;
+
+	if (maxdepth == 0)
+		return eflags;
+
+	/* Short-circuit if we have already visited this node.
+	 */
+	if (root->serial == client->serial)
+		return eflags;
+
+	root->serial = client->serial;
+
+	if (client->flags & PKGCONF_PKG_PKGF_SEARCH_PRIVATE)
+	{
+		PKGCONF_TRACE(client, "%s: collecting private dependencies, level %d", root->id, maxdepth);
+
+		/* XXX: ugly */
+		const unsigned int saved_flags = client->flags;
+		client->flags |= PKGCONF_PKG_PKGF_ITER_PKG_IS_PRIVATE;
+		eflags = pkgconf_queue_collect_dependencies_walk(client, &root->requires_private, data, maxdepth);
+		client->flags = saved_flags;
+		if (eflags != PKGCONF_PKG_ERRF_OK)
+			return eflags;
+	}
+
+	PKGCONF_TRACE(client, "%s: collecting public dependencies, level %d", root->id, maxdepth);
+
+	eflags = pkgconf_queue_collect_dependencies_walk(client, &root->required, data, maxdepth);
+	if (eflags != PKGCONF_PKG_ERRF_OK)
+		return eflags;
+
+	PKGCONF_TRACE(client, "%s: finished, %s", root->id, (root->flags & PKGCONF_PKG_PROPF_VISITED_PRIVATE) ? "private" : "public");
+
+	return eflags;
+}
+
+static inline unsigned int
+pkgconf_queue_collect_dependencies(pkgconf_client_t *client,
+	pkgconf_pkg_t *root,
+	void *data,
+	int maxdepth)
+{
+	++client->serial;
+	return pkgconf_queue_collect_dependencies_main(client, root, data, maxdepth);
 }
 
 static inline unsigned int
 pkgconf_queue_verify(pkgconf_client_t *client, pkgconf_pkg_t *world, pkgconf_list_t *list, int maxdepth)
 {
 	unsigned int result;
+	const unsigned int saved_flags = client->flags;
 	pkgconf_pkg_t initial_world = {
-		.id = "virtual:world",
+		.id = "user:request",
 		.realname = "virtual world package",
 		.flags = PKGCONF_PKG_PROPF_STATIC | PKGCONF_PKG_PROPF_VIRTUAL,
 	};
@@ -241,31 +240,39 @@ pkgconf_queue_verify(pkgconf_client_t *client, pkgconf_pkg_t *world, pkgconf_lis
 		return PKGCONF_PKG_ERRF_DEPGRAPH_BREAK;
 	}
 
-	/* collect all the dependencies */
-	result = pkgconf_pkg_traverse(client, &initial_world, pkgconf_queue_collect_dependents, world, maxdepth, 0);
+	PKGCONF_TRACE(client, "solving");
+	result = pkgconf_pkg_traverse(client, &initial_world, NULL, NULL, maxdepth, 0);
 	if (result != PKGCONF_PKG_ERRF_OK)
 	{
 		pkgconf_solution_free(client, &initial_world);
 		return result;
 	}
 
+	PKGCONF_TRACE(client, "flattening");
+	result = pkgconf_queue_collect_dependencies(client, &initial_world, world, maxdepth);
+	if (result != PKGCONF_PKG_ERRF_OK)
+	{
+		pkgconf_solution_free(client, &initial_world);
+		return result;
+	}
+
+	if (client->flags & PKGCONF_PKG_PKGF_SEARCH_PRIVATE)
+	{
+		PKGCONF_TRACE(client, "marking public deps");
+		client->flags &= ~PKGCONF_PKG_PKGF_SEARCH_PRIVATE;
+		client->flags |= PKGCONF_PKG_PKGF_SKIP_CONFLICTS;
+		result = pkgconf_pkg_traverse(client, &initial_world, pkgconf_queue_mark_public, &world->required, maxdepth, 0);
+		client->flags = saved_flags;
+		if (result != PKGCONF_PKG_ERRF_OK)
+		{
+			pkgconf_solution_free(client, &initial_world);
+			return result;
+		}
+	}
+
 	/* free the initial solution */
 	pkgconf_solution_free(client, &initial_world);
 
-	/* flatten the dependency set using serials.
-	 * we copy the dependencies to a vector, and then erase the list.
-	 * then we copy them back to the list.
-	 */
-	++client->serial;
-
-	PKGCONF_TRACE(client, "flattening requires deps");
-	flatten_dependency_set(client, &world->required);
-
-	++client->serial;
-
-	PKGCONF_TRACE(client, "flattening requires.private deps");
-	flatten_dependency_set(client, &world->requires_private);
-
 	return PKGCONF_PKG_ERRF_OK;
 }
 

man/pc.5

@@ -126,9 +126,10 @@ All dependencies must be satisfied or the pkg-config implementation must not use
 the package.
 (optional; dependency list)
 .It Requires.private
-Required dependencies that must be met for the package to be usable for static linking.
+Required dependencies that must be met for the package to be usable for header
+inclusion and static linking.
 All dependencies must be satisfied or the pkg-config implementation must not use
-the package for static linking.
+the package for header inclusion and static linking.
 (optional; dependency list)
 .It Conflicts
 Dependencies that must not be met for the package to be usable.

meson.build

@@ -1,5 +1,5 @@
 project('pkgconf', 'c',
-  version : '2.1.0',
+  version : '2.2.0',
   license : 'ISC',
   meson_version : '>=0.49',
   default_options : ['c_std=c99'],
@@ -96,8 +96,8 @@ libpkgconf = library('pkgconf',
   'libpkgconf/tuple.c',
   c_args: ['-DLIBPKGCONF_EXPORT', build_static],
   install : true,
-  version : '4.0.0',
-  soversion : '4',
+  version : '5.0.0',
+  soversion : '5',
 )
 
 # For other projects using libpkgconfig as a subproject

pkg.m4

@@ -46,8 +46,8 @@ m4_if(m4_version_compare(PKG_MACROS_VERSION, [$1]), -1,
     [m4_fatal([pkg.m4 version $1 or higher is required but ]PKG_MACROS_VERSION[ found])])
 ])dnl PKG_PREREQ
 
-dnl PKG_PROG_PKG_CONFIG([MIN-VERSION])
-dnl ----------------------------------
+dnl PKG_PROG_PKG_CONFIG([MIN-VERSION], [ACTION-IF-NOT-FOUND])
+dnl ---------------------------------------------------------
 dnl Since: 0.16
 dnl
 dnl Search for the pkg-config tool and set the PKG_CONFIG variable to
@@ -55,6 +55,12 @@ dnl first found in the path. Checks that the version of pkg-config found
 dnl is at least MIN-VERSION. If MIN-VERSION is not specified, 0.9.0 is
 dnl used since that's the first version where most current features of
 dnl pkg-config existed.
+dnl
+dnl If pkg-config is not found or older than specified, it will result
+dnl in an empty PKG_CONFIG variable. To avoid widespread issues with
+dnl scripts not checking it, ACTION-IF-NOT-FOUND defaults to aborting.
+dnl You can specify [PKG_CONFIG=false] as an action instead, which would
+dnl result in pkg-config tests failing, but no bogus error messages.
 AC_DEFUN([PKG_PROG_PKG_CONFIG],
 [m4_pattern_forbid([^_?PKG_[A-Z_]+$])
 m4_pattern_allow([^PKG_CONFIG(_(PATH|LIBDIR|SYSROOT_DIR|ALLOW_SYSTEM_(CFLAGS|LIBS)))?$])
@@ -75,6 +81,9 @@ if test -n "$PKG_CONFIG"; then
 		AC_MSG_RESULT([no])
 		PKG_CONFIG=""
 	fi
+fi
+if test -z "$PKG_CONFIG"; then
+	m4_default([$2], [AC_MSG_ERROR([pkg-config not found])])
 fi[]dnl
 ])dnl PKG_PROG_PKG_CONFIG
 

tests/basic.sh

@@ -231,7 +231,7 @@ libs_circular1_body()
 libs_circular_directpc_body()
 {
 	atf_check \
-		-o inline:"-lcircular-2 -lcircular-3 -lcircular-1\n" \
+		-o inline:"-lcircular-3 -lcircular-1 -lcircular-2\n" \
 		pkgconf --libs ${selfdir}/lib1/circular-3.pc
 }
 

tests/regress.sh

@@ -27,6 +27,9 @@ tests_init \
 	modversion_fullpath \
 	modversion_provides \
 	modversion_uninstalled \
+	modversion_one_word_expression \
+	modversion_two_word_expression \
+	modversion_three_word_expression \
 	pcpath \
 	virtual_variable \
 	fragment_collision \
@@ -301,3 +304,21 @@ modversion_uninstalled_body()
 	atf_check -o inline:"1.2.3\n" \
 		pkgconf --with-path="${selfdir}/lib1" --modversion omg
 }
+
+modversion_one_word_expression_body()
+{
+	atf_check -o inline:"1.2.3\n" \
+		pkgconf --with-path="${selfdir}/lib1" --modversion "foo > 1.0"
+}
+
+modversion_two_word_expression_body()
+{
+	atf_check -o inline:"1.2.3\n" \
+		pkgconf --with-path="${selfdir}/lib1" --modversion foo "> 1.0"
+}
+
+modversion_three_word_expression_body()
+{
+	atf_check -o inline:"1.2.3\n" \
+		pkgconf --with-path="${selfdir}/lib1" --modversion foo ">" 1.0
+}

tests/requires.sh

@@ -10,6 +10,10 @@ tests_init \
 	argv_parse2 \
 	static_cflags \
 	private_duplication \
+	private_duplication_digraph \
+	foo_bar \
+	bar_foo \
+	foo_metapackage_3 \
 	libs_static2 \
 	missing \
 	requires_internal \
@@ -37,7 +41,7 @@ libs_static_body()
 {
 	export PKG_CONFIG_PATH="${selfdir}/lib1"
 	atf_check \
-		-o inline:"-L/test/lib -lbaz -L/test/lib -lzee -L/test/lib -lfoo\n" \
+		-o inline:"-L/test/lib -lbaz -L/test/lib -lzee -lfoo\n" \
 		pkgconf --static --libs baz
 }
 
@@ -45,7 +49,7 @@ libs_static_pure_body()
 {
 	export PKG_CONFIG_PATH="${selfdir}/lib1"
 	atf_check \
-		-o inline:"-L/test/lib -lbaz -L/test/lib -lfoo\n" \
+		-o inline:"-L/test/lib -lbaz -lfoo\n" \
 		pkgconf --static --pure --libs baz
 }
 
@@ -69,10 +73,46 @@ private_duplication_body()
 {
 	export PKG_CONFIG_PATH="${selfdir}/lib1"
 	atf_check \
-		-o inline:"-lprivate -lbaz -lzee -lbar -lfoo -lfoo\n" \
+		-o inline:"-lprivate -lbaz -lzee -lbar -lfoo\n" \
 		pkgconf --static --libs-only-l private-libs-duplication
 }
 
+private_duplication_digraph_body()
+{
+	export PKG_CONFIG_PATH="${selfdir}/lib1"
+	atf_check \
+		-o 'match:"user:request" -> "private-libs-duplication"' \
+		-o 'match:"private-libs-duplication" -> "bar"' \
+		-o 'match:"private-libs-duplication" -> "baz"' \
+		-o 'match:"bar" -> "foo"' \
+		-o 'match:"baz" -> "foo"' \
+		pkgconf --static --libs-only-l private-libs-duplication --digraph
+}
+
+bar_foo_body()
+{
+	export PKG_CONFIG_PATH="${selfdir}/lib1"
+	atf_check \
+		-o inline:"-lbar -lfoo\n" \
+		pkgconf --static --libs-only-l bar foo
+}
+
+foo_bar_body()
+{
+	export PKG_CONFIG_PATH="${selfdir}/lib1"
+	atf_check \
+		-o inline:"-lbar -lfoo\n" \
+		pkgconf --static --libs-only-l foo bar
+}
+
+foo_metapackage_3_body()
+{
+	export PKG_CONFIG_PATH="${selfdir}/lib1"
+	atf_check \
+		-o inline:"-lbar -lfoo\n" \
+		pkgconf --static --libs-only-l foo metapackage-3
+}
+
 libs_static2_body()
 {
 	export PKG_CONFIG_PATH="${selfdir}/lib1"