[Rd] Possible bug in package installation when R_ICU_LOCALE is set

[Korpela Mikko (MML)]

On a Windows computer (other platforms not tested), installing a
package from source may fail if the environment variable R_ICU_LOCALE
is set, depending on the package and the locale.

For example, after setting R_ICU_LOCALE to "fi_FI",

  install.packages("seriation", type = "source")

(package version 1.2-3) fails with the following error:

** preparing package for lazy loading
Error in set_criterion_method("dist", "AR_events", criterion_ar_events,  :
  could not find function "set_criterion_method"
Error : unable to load R code in package 'seriation'

Package "Epi" (version 2.24) fails similarly:

** preparing package for lazy loading
Error in eval(exprs[i], envir) : object 'Relevel.default' not found
Error : unable to load R code in package 'Epi'

Whether R_ICU_LOCALE is set before R is launched or during the session
doesn't matter: installation of these two example packages fails
either way. If R_ICU_LOCALE is unset, calling

  icuSetCollate(locale = "fi_FI")

is harmless. Browsing through the R manuals, I did not find warnings
against using R_ICU_LOCALE, or any indication why package installation
should fail with the variable being set. About the collation order of R
code files, "Writing R Extensions" says:

> The default is to collate according to the 'C' locale.

I interpret this (and the surrounding text) as a "promise" to package
developers that no matter what the end user does, the developer should
be able to rely on the collation order being 'C' unless the developer
defines another order.

> sessionInfo()
R version 3.4.3 Patched (2018-02-03 r74231)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

Matrix products: default

locale:
[1] LC_COLLATE=Finnish_Finland.1252  LC_CTYPE=Finnish_Finland.1252
[3] LC_MONETARY=Finnish_Finland.1252 LC_NUMERIC=C
[5] LC_TIME=Finnish_Finland.1252

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

loaded via a namespace (and not attached):
[1] compiler_3.4.3 tools_3.4.3

-- 
Mikko Korpela
Chief Expert, Valuations
National Land Survey of Finland
Opastinsilta 12 C, FI-00520 Helsinki, Finland
+358 50 462 6082
www.maanmittauslaitos.fi