MergeProcess: add fallback setcpv call

It's important that this metadata access happens in the parent process,
since closing of file descriptors in the subprocess can prevent access
to open database connections such as that used by the sqlite metadata
cache module.

1 files changed, 19 insertions, 3 deletions

diff --git a/pym/portage/dbapi/_MergeProcess.py b/pym/portage/dbapi/_MergeProcess.py
index ea7c3e6d6..afb2e084d 100644
--- a/pym/portage/dbapi/_MergeProcess.py
+++ b/pym/portage/dbapi/_MergeProcess.py
@@ -30,6 +30,21 @@ class MergeProcess(SpawnProcess):
 		'_buf', '_elog_keys')
 
 	def _start(self):
+		# Portage should always call setcpv prior to this
+		# point, but here we have a fallback as a convenience
+		# for external API consumers. It's important that
+		# this metadata access happens in the parent process,
+		# since closing of file descriptors in the subprocess
+		# can prevent access to open database connections such
+		# as that used by the sqlite metadata cache module.
+		cpv = "%s/%s" % (self.mycat, self.mypkg)
+		settings = self.settings
+		if cpv != settings.mycpv or \
+			"IUSE" not in settings.configdict["pkg"]:
+			settings.reload()
+			settings.reset()
+			settings.setcpv(cpv, mydb=self.mydbapi)
+
 		self._handle_self_reinstall()
 		super(MergeProcess, self)._start()
 
@@ -116,9 +131,10 @@ class MergeProcess(SpawnProcess):
 			fcntl.fcntl(elog_reader_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
 		blockers = None
 		if self.blockers is not None:
-			# Query blockers in the main process, since metadata cache
-			# queries may not work for some databases from within a
-			# subprocess. For example, sqlite is known to misbehave.
+			# Query blockers in the main process, since closing
+			# of file descriptors in the subprocess can prevent
+			# access to open database connections such as that
+			# used by the sqlite metadata cache module.
 			blockers = self.blockers()
 		mylink = self.dblink(self.mycat, self.mypkg, settings=self.settings,
 			treetype=self.treetype, vartree=self.vartree,