[R-pkg-devel] "Undefined global functions or variables" locally but NOT on GitHub

[Duncan Murdoch]

On 2025-10-14 5:16 a.m., Chris Black wrote:
> 
> 
>> On Oct 14, 2025, at 1:38 AM, Georgi Boshnakov <georgi.boshnakov using manchester.ac.uk> wrote:
>>
>> So, you can't access them with the '::' operator, you need to use data().
> 
> You can, though!
> 
> ```
> % R --vanilla -q -e 'datasets::AirPassengers'
>> datasets::AirPassengers
>       Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
> 1949 112 118 132 129 121 135 148 148 136 119 104 118
> 1950 115 126 141 135 125 149 170 170 158 133 114 140
> 1951 145 150 178 163 172 178 199 199 184 162 146 166
> 1952 171 180 193 181 183 218 230 242 209 191 172 194
> 1953 196 196 236 235 229 243 264 272 237 211 180 201
> 1954 204 188 235 227 234 264 302 293 259 229 203 229
> 1955 242 233 267 269 270 315 364 347 312 274 237 278
> 1956 284 277 317 313 318 374 413 405 355 306 271 306
> 1957 315 301 356 348 355 422 465 467 404 347 305 336
> 1958 340 318 362 348 363 435 491 505 404 359 310 337
> 1959 360 342 406 396 420 472 548 559 463 407 362 405
> 1960 417 391 419 461 472 535 622 606 508 461 390 432
> ```
> 
> This is also explicit in R Internals 1.17 ([1], emphasis added): "Lazy-load databases are loaded into the exports for a package, but not into the namespace environment itself. Thus they are visible when the package is attached, ***and also via the :: operator.***”
> 
> [1] https://cran.r-project.org/doc/manuals/r-release/R-ints.html#Lazy-loading

That's true provided the data is lazy-loaded.  The default is "LazyData: 
false", but "LazyData: true" is a pretty common choice because 
usethis::use_data() puts that in DESCRIPTION.

Duncan Murdoch