rrs_upgrade_history.py stalls indefinitely when it reaches OE-Core
commit 3c00ad5d3b ("build-appliance-image: Update to master head
revisions", 2026-02-27).

OE-Core 5596ea156d ("bitbake.conf: Switch BB_SIGNATURE_HANDLER to
OEEquivHash by default") changed the default signature handler, and
BB_HASHSERVE ??= "auto" was only added in the following commit,
4a388406ac ("bitbake.conf: Set BB_HASHSERVE alongside
BB_SIGNATURE_HANDLER"). 3c00ad5d3b is the only commit in between that
touches a recipe, so RRS parses it. Parsing it fails in
meta/lib/oe/sstatesig.py with:

  ERROR: OEEquivHash requires BB_HASHSERVE to be set

The error is raised in the BitBake server during tinfoil setup, and
the BitBake of that period (bc8be83aef) doesn't return it to the
client, so upgrade_history_internal.py never exits. run_internal()
ignores non-zero exits and would move on, but it has no timeout, so
the whole run stalls until it is killed. On layers.moto-timo.net it
sat idle for ~7.5 hours.

The layer index parse configuration (conf/local.conf) doesn't need
hash equivalence at all. Since 4a388406ac, OE-Core master also starts
a local hashserv for every layer index / RRS parse.

Proposed fix: set BB_SIGNATURE_HANDLER = "OEBasicHash" in
layerindex-web's conf/local.conf. This fixes the bad revision and
avoids the per-parse hashserv on current master.

Possible follow-up: add a per-commit timeout to run_internal() so any
future hang becomes a logged failure instead of stalling the run.