To clarify: we do content-based hashing, and when we say "shared bytes aren’t guaranteed to be in the exact same container image layer", what we mean is that
FROM some/image
RUN pip install torch==2.7.1
and
FROM another/image
RUN pip install torch==2.7.1
will produce images with very high overlap in contents, which will be shared by a content-based cache, but those images' final layers are disjoint from the perspective of a layerwise cache.
FROM some/image RUN pip install torch==2.7.1
and
FROM another/image RUN pip install torch==2.7.1
will produce images with very high overlap in contents, which will be shared by a content-based cache, but those images' final layers are disjoint from the perspective of a layerwise cache.