The manifest resolver loaded OrcaFilamentLibrary once per vendor it
resolved through, so a run that mixes vendors parsed the library tree
again for each of them. The library is now cached like any other vendor
tree, keyed on its root and substitution rule, and doubles as the base
every vendor under that root loads against. A vendor bundle only reads
from its base while loading, so sharing the instance is safe.
The cache key carries the substitution rule as its enum, and the lookup
lambdas take a const bundle since they only read.
Hanif Koh
d5cf1502c4