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| author | Silvan Mosberger <contact@infinisil.com> | 2023-11-14 07:42:59 +0100 |
|---|---|---|
| committer | Silvan Mosberger <silvan.mosberger@tweag.io> | 2023-11-15 01:20:36 +0100 |
| commit | 1c3eb9eff1b864bf49c3661558b495235fc3b3b4 (patch) | |
| tree | 8d72c4ef51a603588ec1c9dab6fde4a323369872 /lib/fileset/README.md | |
| parent | terraform-providers.baiducloud: 1.19.19 -> 1.19.20 (diff) | |
| download | nixpkgs-1c3eb9eff1b864bf49c3661558b495235fc3b3b4.tar.gz | |
lib.fileset.fileFilter: Restrict second argument to paths
While this change is backwards-incompatible, I think it's okay because:
- The `fileFilter` function is not yet in a stable NixOS release, it was only merged about [a month ago](https://github.com/NixOS/nixpkgs/pull/257356).
- All public uses of the function on GitHub only pass a path
- Any `fileFilter pred fileset` can also be expressed as `intersection fileset (fileFilter pred path)` without loss of functionality.
- This is furthermore pointed out in the new error message when a file set is passed
Diffstat (limited to 'lib/fileset/README.md')
| -rw-r--r-- | lib/fileset/README.md | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/lib/fileset/README.md b/lib/fileset/README.md index 91f892a1be95..14b6877a9065 100644 --- a/lib/fileset/README.md +++ b/lib/fileset/README.md @@ -238,6 +238,21 @@ Arguments: And it would be unclear how the library should behave if the one file wouldn't be added to the store: `toSource { root = ./file.nix; fileset = <empty>; }` has no reasonable result because returing an empty store path wouldn't match the file type, and there's no way to have an empty file store path, whatever that would mean. +### `fileFilter` takes a path + +The `fileFilter` function takes a path, and not a file set, as its second argument. + +- (-) Makes it harder to compose functions, since the file set type, the return value, can't be passed to the function itself like `fileFilter predicate fileset` + - (+) It's still possible to use `intersection` to filter on file sets: `intersection fileset (fileFilter predicate ./.)` + - (-) This does need an extra `./.` argument that's not obvious + - (+) This could always be `/.` or the project directory, `intersection` will make it lazy +- (+) In the future this will allow `fileFilter` to support a predicate property like `subpath` and/or `components` in a reproducible way. + This wouldn't be possible if it took a file set, because file sets don't have a predictable absolute path. + - (-) What about the base path? + - (+) That can change depending on which files are included, so if it's used for `fileFilter` + it would change the `subpath`/`components` value depending on which files are included. +- (+) If necessary, this restriction can be relaxed later, the opposite wouldn't be possible + ## To update in the future Here's a list of places in the library that need to be updated in the future: |