Possible regression in DRC: with_density influences join operation

akrinke

The following DRC script changes its behavior in hierarchical layouts after version 0.29.7:

report("drc")

deep

Activ = source.polygons("1/0")
Cont = source.polygons("6/0")

# commenting the following line produces the expected result
Activ.with_density(0.0 .. 0.35, tile_size(20.0.um))

Cont.output("Cont")
Activ.output("Activ")
Cont.join(Activ).output("Cont.join(Activ)")

In 0.29.7, the two hierarchical layers are properly joined. In later versions (I've checked 0.29.9 and 0.29.11), the join is missing shapes in lower hierarchy levels. Disabling the density check produces the correct/expected result! Interestingly, even Activ.dup.with_density(...) changes the behavior of the join operation!

I have compiled all versions from source on Arch Linux. Can anyone reproduce this issue? If required, I can also create a simple example layout.

Matthias

Hi Andreas,

sorry for the late reply.

I can reproduce the issue on the attached layout.

Interestingly, if I write the "join" output to a layer, everything is fine:

deep

Activ = source.polygons("1/0")
Cont = source.polygons("6/0")

Activ.with_density(0.0 .. 0.35, tile_size(20.0.um))

Cont.output("Cont")
Activ.output("Activ")
Cont.join(Activ).output(100, 0)

I have created a ticket for this case: https://github.com/KLayout/klayout/issues/1993

Thanks for reporting that issue.

Matthias

akrinke

Hi Matthias,

thank you for checking and creating the issue! It is interesting that the output to a layer is not affected. So maybe it's the RDB output?

I thought about doing a git bisect but was afraid of the compile times
Next time, I will try to provide a test layout right away.

Andreas

Matthias

No worries. I have found the root cause which was a dangling reference that the GC did not clean up (or not quickly enough).

I fixed that and will release it in 0.29.12 soon.

Matthias

akrinke

Thank you very much!

Andreas