tree 1af6dd75b6b07a594a37c7422539755c8200b39b
parent 4a4564510445ba1dd9831cea3acddc2b29f85f03
author Gavin Li <git@thegavinli.com> 1761791503 +0000
committer Michael Stapelberg <stapelberg@google.com> 1762250218 -0800

internal/encoding/tag: use proto3 defaults if proto3

proto3 legacy struct field tags are improperly parsed as proto2,
resulting in fd.L1.EditionFeatures.IsFieldPresence set to true when it
should have been false. This causes coderFieldInfo.isPointer to be true
for said fields. When the encode process (particularly
MessageInfo.sizePointerSlow) sees isPointer=true for the field, it
attempts to interpret the field as a pointer, which results in a "fatal
error: checkptr: misaligned pointer conversion" runtime error if the
field address happens to not be pointer-aligned. This only happens if
building with -race/-asan/-msan as they enable checkptr.

To avoid this issue, parse from proto3 edition defaults if the proto3
key is found in the struct field tag.

Change-Id: Id81ab38fe7efd437d0748a485653d27b1acc3afb
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/716360
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Reviewed-by: Nicolas Hillegeer <aktau@google.com>
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