controller.capnp declared `struct Data $C.mapname("xce_data_t")` (an
OPCode_get query-result tagged union) at file scope, which shadows
Cap'n Proto's builtin Data blob type for every later `: Data` field in
the same file. This silently miscompiled 7 fields across 6 structs as
a struct-pointer type instead of a raw byte blob: UpgradeConfigRequest
.sha256/.bytes, ReplConfigReply.sha256/.bytes, ReplConfigPushRequest
.sha256/.bytes, ReplEnvelope.payload, SnapshotTransfer's chunk
payload, WalCatchupEntry.payload/.batchPayloads, and CtrlHelloRequest
.key. Production C code had already routed around it for years via
hand-rolled raw capn_ptr manipulation (see request.c's own comments);
nothing before now needed the generated codec/accessors to actually
work for these fields.
Renamed the local struct to XceData (capnp-level name only; the
$C.mapname("xce_data_t") C typedef is unchanged) and explicitly
repointed getdata/pushmsg at XceData by name, since those two fields
correctly want the local tagged union. Updated every derived
generated-identifier reference across 19 hand-written files spanning
controller, lib, scheduler, and the Go apiserver/xcecli CGo bindings.
Fixed 5 call sites in lib/request.c that had been typed against the
old workaround alias but now legitimately receive the correct
capn_data type (a pure type-name swap -- Data_ptr/XceData_ptr and
capn_data share the identical {capn_ptr p} layout).
Verified via full rebuild+test: lib (1/1), controller (3/3, incl. the
job-array push regression tests), scheduler (15/15), Go apiserver +
xcecli (all packages green), and a direct pycapnp round-trip proving
UpgradeConfigRequest.sha256/.bytes now encode/decode correctly.
Bug: bug-1461 (.wolf/buglog.json). Unblocks admin-config-tool task 3.3.
Rongsong Shen
e53c086ec5