[help] How to have a file target stay up to date when moving it to a new machine where the file path changes but the file doesn't

[kendonB]

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Description

I have a target of the form:

  tar_target(
    polygons_parquet_path,
    {
      output_path <- file.path(
        raw_data_directory,
        "output.parquet"
      )

      # code to make the parquet
      output_path
    },
    format = "file"
  ),

and when I upload my targets pipeline to a different machine, including this file, but change raw_data_directory, this one goes out of date (at least because the dependency raw_data_directory has changed).

But, when I change it to keep raw_data_directory the same in R and use the OS to create a symlink on the first machine, it still goes out of date. Should that work? Any advice on troubleshooting?

The tar_meta() calls are identical, other than the data field following remaking the target on the new machine.

Any troubleshooting tips?

[wlandau]

Sounds like you're keeping the output_path file path constant. Recent versions of targets use secretbase::siphash13(file = path) for hashing files. You could see if the difference happens at that level when you download and symlink a file.

[kendonB]

Tried to reproduce again and it seemed to work as expected. Was likely a mistake on my part earlier failing to upload the updated file target and just uploading the _targets folder.