Add force-mirror FEATURE.

pym/portage/package/ebuild/fetch.py

Index: pym/portage/package/ebuild/fetch.py
diff --git a/pym/portage/package/ebuild/fetch.py b/pym/portage/package/ebuild/fetch.py
index c33375ca6afca6fb70f482dc5cea8b550f527449..6e4c728ec27b48872b53d158a7d356566ab973fc 100644
--- a/pym/portage/package/ebuild/fetch.py
+++ b/pym/portage/package/ebuild/fetch.py
@@ -245,8 +245,8 @@ def fetch(myuris, mysettings, listonly=0, fetchonly=0,
 	userpriv = secpass >= 2 and "userpriv" in features
 
 	# 'nomirror' is bad/negative logic. You Restrict mirroring, not no-mirroring.
-	if "mirror" in restrict or \
-	   "nomirror" in restrict:
+	restrict_mirror = "mirror" in restrict or "nomirror" in restrict
+	if restrict_mirror:
 		if ("mirror" in features) and ("lmirror" not in features):
 			# lmirror should allow you to bypass mirror restrictions.
 			# XXX: This is not a good thing, and is temporary at best.
@@ -344,8 +344,7 @@ def fetch(myuris, mysettings, listonly=0, fetchonly=0,
 	if "local" in custommirrors:
 		mymirrors += custommirrors["local"]
 
-	if "nomirror" in restrict or \
-	   "mirror" in restrict:
+	if restrict_mirror:
 		# We don't add any mirrors.
 		pass
 	else:
@@ -374,6 +373,7 @@ def fetch(myuris, mysettings, listonly=0, fetchonly=0,
 			del mymirrors[x]
 
 	restrict_fetch = "fetch" in restrict
+	force_mirror = "force-mirror" in features and not restrict_mirror
 	custom_local_mirrors = custommirrors.get("local", [])
 	if restrict_fetch:
 		# With fetch restriction, a normal uri may only be fetched from
@@ -430,7 +430,7 @@ def fetch(myuris, mysettings, listonly=0, fetchonly=0,
 				writemsg(_("Invalid mirror definition in SRC_URI:\n"), noiselevel=-1)
 				writemsg("  %s\n" % (myuri), noiselevel=-1)
 		else:
-			if restrict_fetch:
+			if restrict_fetch or force_mirror:
 				# Only fetch from specific mirrors is allowed.
 				continue
 			if "primaryuri" in restrict: