internal/pkg: drop cached error on cancel

This avoids disabling the artifact when using the individual cancel method. Unfortunately this makes the method blocking.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/pkg.go

@@ -1120,7 +1120,7 @@ func (c *Cache) Done(id unique.Handle[ID]) <-chan struct{} {
 
 // Cancel cancels the ongoing cure of an [Artifact] referred to by the specified
 // identifier. Cancel returns whether the [context.CancelFunc] has been killed.
-// Cancel does not wait for the cure to complete.
+// Cancel returns after the cure is complete.
 func (c *Cache) Cancel(id unique.Handle[ID]) bool {
 	c.identMu.RLock()
 	pending, ok := c.identPending[id]
@@ -1129,6 +1129,13 @@ func (c *Cache) Cancel(id unique.Handle[ID]) bool {
 		return false
 	}
 	pending.cancel()
+	<-pending.done
+
+	c.abortMu.Lock()
+	c.identMu.Lock()
+	delete(c.identErr, id)
+	c.identMu.Unlock()
+	c.abortMu.Unlock()
 	return true
 }