[Bioc-devel] Resource temporarily unavailable error with rtracklayer

Hello,

a user of the CAGEr package reported an error that occurs when it calls 
the `export.bw` function of rtracklayer:

rsession: 1730343 1730344 doesn't intersect 1892288 1899678, chromId 6 
chromSize 5022195: Resource temporarily unavailable
Error in isSingleString(path) : UCSC library operation failed
In addition: Warning message:
In isSingleString(path) : Internal error ucsc/bbiWrite.c 414

This is triggered by a GRanges object that has 236595 lines and 13304 
seqlevels.  My attempts to bisect the object to find a defective line 
did not succeed; but it seems important that I keep most of the contents 
to trigger the error.  I therefore wonder if the problem is either the 
number of lines or the number of seqlevels.

Not being very familiar with the BigWig format and the internals of 
rtracklayer, I am a bit lost.

Can somebody suggest me a way to solve the problem ?

Have a nice day,

Charles

R version 4.0.2 (2020-06-22)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Debian GNU/Linux bullseye/sid

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0

locale:
  [1] LC_CTYPE=en_GB.UTF-8       LC_NUMERIC=C 
LC_TIME=en_GB.UTF-8
  [4] LC_COLLATE=en_GB.UTF-8     LC_MONETARY=en_GB.UTF-8 
LC_MESSAGES=en_GB.UTF-8
  [7] LC_PAPER=en_GB.UTF-8       LC_NAME=C                  LC_ADDRESS=C 

[10] LC_TELEPHONE=C             LC_MEASUREMENT=en_GB.UTF-8 
LC_IDENTIFICATION=C

attached base packages:
[1] parallel  stats4    stats     graphics  grDevices utils     datasets 
  methods
[9] base

other attached packages:
  [1] CAGEr_1.31.3                MultiAssayExperiment_1.15.2
  [3] SummarizedExperiment_1.19.5 DelayedArray_0.15.6
  [5] matrixStats_0.56.0          Matrix_1.2-18
  [7] Biobase_2.49.0              GenomicRanges_1.41.5
  [9] GenomeInfoDb_1.25.8         IRanges_2.23.10
[11] S4Vectors_0.27.12           BiocGenerics_0.35.4

loaded via a namespace (and not attached):
  [1] Rcpp_1.0.5               stringdist_0.9.5.5       lattice_0.20-41 

  [4] formula.tools_1.7.1      Rsamtools_2.5.3 
Biostrings_2.57.2
  [7] gtools_3.8.2             digest_0.6.25            R6_2.4.1 

[10] plyr_1.8.6               ggplot2_3.3.2            pillar_1.4.5 

[13] zlibbioc_1.35.0          rlang_0.4.7              rstudioapi_0.11 

[16] data.table_1.12.8        vegan_2.5-6              splines_4.0.2 

[19] BiocParallel_1.23.2      RCurl_1.98-1.2           munsell_0.5.0 

[22] compiler_4.0.2           rtracklayer_1.49.3       pkgconfig_2.0.3 

[25] mgcv_1.8-31              tidyselect_1.1.0         tibble_3.0.2 

[28] GenomeInfoDbData_1.2.3   XML_3.99-0.4             reshape_0.8.8 

[31] permute_0.9-5            crayon_1.3.4             dplyr_1.0.0 

[34] GenomicAlignments_1.25.3 MASS_7.3-51.6            bitops_1.0-6 

[37] grid_4.0.2               nlme_3.1-148             gtable_0.3.0 

[40] lifecycle_0.2.0          magrittr_1.5             scales_1.1.1 

[43] KernSmooth_2.23-17       stringi_1.4.6            som_0.3-5.1 

[46] XVector_0.29.3           ellipsis_0.3.1           generics_0.0.2 

[49] vctrs_0.3.1              tools_4.0.2              BSgenome_1.57.4 

[52] glue_1.4.1               purrr_0.3.4              colorspace_1.4-1 

[55] cluster_2.1.0            operator.tools_1.6.3     beanplot_1.2 

[58] memoise_1.1.0            VGAM_1.1-3