libdpkg: Register all pending triggers for deferred processing

Trigger processing on the deferred stage is just opportunistic, but
we enqueue all currently pending triggers that might have been
activated on a previous unpack run, only when being called as
«dpkg --configure pkgname…».

This is a mostly conformant workaround for frontends like apt that do
not correctly call «dpkg --configure -a» or «dpkg --triggers-only -a»
after their normal runs, and leave packages in triggers-pending and
triggers-awaited states.

Closes: #766758

1 files changed, 38 insertions, 0 deletions

diff --git a/src/trigproc.c b/src/trigproc.c
index 4d61d7054..ea91c7400 100644
--- a/src/trigproc.c
+++ b/src/trigproc.c
@@ -103,6 +103,44 @@ trigproc_enqueue_deferred(struct pkginfo *pend)
 	      pkg_name(pend, pnaw_always));
 }
 
+/**
+ * Populate the deferred trigger queue.
+ *
+ * When dpkg is called with a specific set of packages to act on, we might
+ * have packages pending trigger processing. But because there are frontends
+ * that do not perform a final «dpkg --configure --pending» call (i.e. apt),
+ * the system is left in a state with packages not fully installed.
+ *
+ * We have to populate the deferred trigger queue from the entire package
+ * database, so that we might try to do opportunistic trigger processing
+ * when going through the deferred trigger queue, because a fixed apt will
+ * not request the necessary processing anyway.
+ *
+ * XXX: This can be removed once apt is fixed in the next stable release.
+ */
+void
+trigproc_populate_deferred(void)
+{
+	struct pkgiterator *iter;
+	struct pkginfo *pkg;
+
+	iter = pkg_db_iter_new();
+	while ((pkg = pkg_db_iter_next_pkg(iter))) {
+		if (!pkg->trigpend_head)
+			continue;
+
+		if (pkg->status != PKG_STAT_TRIGGERSAWAITED &&
+		    pkg->status != PKG_STAT_TRIGGERSPENDING)
+			continue;
+
+		if (pkg->want != PKG_WANT_INSTALL)
+			continue;
+
+		trigproc_enqueue_deferred(pkg);
+	}
+	pkg_db_iter_free(iter);
+}
+
 void
 trigproc_run_deferred(void)
 {