C stack usage is too close to the limit when loading a LAScatalog

[Jean-Romain]

In the multithreading development branch there is one unit test that is failling for very weird reasons. If a LAScatalog from lidR is loaded it crashes the session with Erreur : C stack usage is too close to the limit. This typically comes from conccurent call to R's C API but here no call to R's C API is used.

library(lasR)

set_lasr_strategy(concurrent_files(2))

LASfile <- system.file("extdata", "Example.las", package="lasR")
las = lidR::readLAScatalog(LASfile)

f <- system.file("extdata", "bcts/", package="lasR")
f = list.files(f, full.names = TRUE, pattern = "\\.laz")
f = f[1:2]

read = reader(f)
bound = hulls()
pipeline = read+bound
pipeline
processor(pipeline, verbose = T)
# > Erreur : C stack usage  17652210908 is too close to the limit

Removing las = lidR::readLAScatalog(LASfile) it works.

After investigations, it fails because lidR::is.overlapping() is called internally. Using a modified version that does not call lidR::is.overlapping() it works. After more investigation and using a modified version without is.overlapping() it can still fail using

las = lidR::readLAScatalog(LASfile)
sfdf = las@data

But

las = lidR::readLAScatalog(LASfile)
las@data

does work !!

After even more investigations the error is called into the vector writer by polygon.IsValid(). Removing this line it works despite it has 0 relationship with a LAScatalog not even used.

lasR/src/LASR/Vector.cpp

Line 257 in b5d0898

if (!polygon.IsValid())

I was also able to reproduce loading testthat but it was inconsistent.