1 files changed, 21 insertions, 6 deletions

diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index 1fa8a63d17..8e8efd18d5 100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -1146,14 +1146,18 @@ python sstate_eventhandler() {
 
 SSTATE_PRUNE_OBSOLETEWORKDIR ?= "1"
 
-# Event handler which removes manifests and stamps file for
-# recipes which are no longer reachable in a build where they
-# once were.
+#
+# Event handler which removes manifests and stamps file for recipes which are no
+# longer 'reachable' in a build where they once were. 'Reachable' refers to
+# whether a recipe is parsed so recipes in a layer which was removed would no
+# longer be reachable. Switching between systemd and sysvinit where recipes
+# became skipped would be another example.
+#
 # Also optionally removes the workdir of those tasks/recipes
 #
-addhandler sstate_eventhandler2
-sstate_eventhandler2[eventmask] = "bb.event.ReachableStamps"
-python sstate_eventhandler2() {
+addhandler sstate_eventhandler_reachablestamps
+sstate_eventhandler_reachablestamps[eventmask] = "bb.event.ReachableStamps"
+python sstate_eventhandler_reachablestamps() {
     import glob
     d = e.data
     stamps = e.stamps.values()
@@ -1224,6 +1228,17 @@ python sstate_eventhandler2() {
         os.remove(preservestampfile)
 }
 
+
+#
+# Bitbake can generate an event showing which setscene tasks are 'stale',
+# i.e. which ones will be rerun. These are ones where a stamp file is present but
+# it is stable (e.g. taskhash doesn't match). With that list we can go through
+# the manifests for matching tasks and "uninstall" those manifests now. We do
+# this now rather than mid build since the distribution of files between sstate
+# objects may have changed, new tasks may run first and if those new tasks overlap
+# with the stale tasks, we'd see overlapping files messages and failures. Thankfully
+# removing these files is fast.
+#
 addhandler sstate_eventhandler_stalesstate
 sstate_eventhandler_stalesstate[eventmask] = "bb.event.StaleSetSceneTasks"
 python sstate_eventhandler_stalesstate() {