Before this, there was a bug triggered under the following conditions:
1. An overlay snapshotter was being used, which caused the optimization
of preparing a new snapshot off of the base layers to be triggered
2. The base layers contained a directory that had contents
3. One subsequent layer deleted that directory w/out recreating it
4. A later layer recreated the directory
In this case, what happened was a whiteout device would be created as
part of 3 above but then in step 4 the whiteout device would be removed
and replaced with a plain directory. The problem is that such a
directory doesn't block out the files from step 2 and it doesn't know
about them because they are in a lowerdir (not the upperdir being
applied to).
The simplest fix, which this commit implements, is to just set the
directory created in step 4 as opaque, which enables the correct
behavior of blocking out files below it.
This was missed in test coverage before because tests for opaque
handling always combined 3+4 into one layer, whereas the bug requires
they be separate layers. A new integration test has been added to cover
this case.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
The merge diff tests were using some common LLB state objects across
multiple test cases, which each have their own buildkit client and ran
in parallel. The LLB client library does not appear to currently work
with such use cases where LLB states are shared, with errors about
concurrent map writes to marshal state constraints occasionally being
hit during test runs.
Until that issue is addressed (or it's made explicit that the LLB client
library is not expected to work in such a way), this works around the
problem by not sharing states and instead using common funcs that return
distinct state instances.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
This change enables inline cache to work as expected with MergeOp by
supporting a new type of result, DiffResult, which enables results to be
specified as a specific ordered set of layers inside an image.
Previously, results could only be specified with a singe layer index,
which meant that they had to start at the image's base layer and end at
that index. That meant that merge inputs couldn't be specified as they
are often a subset of the image layers that don't begin at the base.
Signed-off-by: Erik Sipsma <erik@sipsma.dev>
Erik Sipsma
Tonis Tiigi