H17: the .n read-modify-write hard-coded a DINT parent. On an INT or SINT host
(both legal in Logix, and reads of Flags.3 there already worked) the DINT
decode of a 2-byte buffer threw OutOfBounds, the generic catch evicted the BIT
tag's (non-existent) runtime and reported BadCommunicationError + Degraded.
The parent width now comes from the parent read's size (1 SINT / 2 INT /
4 DINT / 8 LINT; unknown keeps the DINT assumption). Narrow hosts use unsigned
arithmetic so a set top bit encodes without overflow; a bit past the host's
width is BadOutOfRange and a non-integer width BadTypeMismatch, both refused
before anything is written, warned once, no health write. A transport failure
in the RMW now evicts the parent runtime it actually used. Native end-to-end:
an INT host is written as ONE INT (type 0xC3, 2 bytes).
Refs #737
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty
cb16ebc75e