Assert on matching channel size for duplicate channel IDs in TlmPacke…#5357
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Sammy-Dabbas wants to merge 1 commit into
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Assert on matching channel size for duplicate channel IDs in TlmPacke…#5357Sammy-Dabbas wants to merge 1 commit into
Sammy-Dabbas wants to merge 1 commit into
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…tizer TlmEntry.channelSize was overwritten each time a channel ID recurred across packets, so a channel declared with different sizes in two packets corrupted the earlier packet's buffer offsets and overflowed the fill buffer during TlmRecv/TlmGet copies. Stamp the size on the first sighting and assert equality on subsequent sightings, mirroring the duplicate-detection assert already used for the ignore list. Identical duplicates across packets are still allowed. Fixes nasa#5132.
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Change Description
TlmPacketizer's
setPacketListstores each channel's serialized size in a singleTlmEntry.channelSize. When the same channel ID appears in more than one packet, the loop overwrote that size with the last-seen value, so the earlier packet's buffer offsets (computed from the original size) no longer matched. The runtimememcpyinTlmRecv_handler/TlmGet_handlercould then read or write past the channel's slot and overflow the fill buffer.This stamps the size on the first sighting of a channel ID and
FW_ASSERTs that any later sighting has the same size, mirroring the duplicate detection assert already present in the ignore-list loop. Identical-definition duplicates across packets behave exactly as before; a conflicting definition trips a configuration-time assert before any buffer is used.Rationale
Fixes #5132. Per @LeStarch's clarification on the issue, a channel ID may repeat across packets as long as its definition is identical, so this allows matching duplicates and rejects only conflicting sizes.
Testing/Review Recommendations
Two unit tests added in
Svc/TlmPacketizer/test/ut:DuplicateChannelIdMatchingSizeTestconfirms an identical-size duplicate across two packets is accepted and both packets emit;DuplicateChannelIdConflictingSizeTestconfirms a conflicting size trips the assert viaASSERT_DEATH_IF_SUPPORTED. I could not build locally (no C++ toolchain), so please rely on CI for the compile and unit-test run.Future Work
None.
AI Usage (see policy)
No