Merge pull request #267384 from tweag/fileset.fileFilter-path2

`fileset.fileFilter`: Restrict second argument to paths
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Robert Hensing 2023-11-16 00:34:04 +01:00 committed by GitHub
commit 060c4ad377
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4 changed files with 52 additions and 31 deletions

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@ -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:

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@ -366,7 +366,7 @@ in {
type :: String,
...
} -> Bool)
-> FileSet
-> Path
-> FileSet
Example:
@ -397,14 +397,24 @@ in {
Other attributes may be added in the future.
*/
predicate:
# The file set to filter based on the predicate function
fileset:
# The path whose files to filter
path:
if ! isFunction predicate then
throw ''
lib.fileset.fileFilter: First argument is of type ${typeOf predicate}, but it should be a function instead.''
else if ! isPath path then
if path._type or "" == "fileset" then
throw ''
lib.fileset.fileFilter: Second argument is a file set, but it should be a path instead.
If you need to filter files in a file set, use `intersection fileset (fileFilter pred ./.)` instead.''
else
throw ''
lib.fileset.fileFilter: Second argument is of type ${typeOf path}, but it should be a path instead.''
else if ! pathExists path then
throw ''
lib.fileset.fileFilter: Second argument (${toString path}) is a path that does not exist.''
else
_fileFilter predicate
(_coerce "lib.fileset.fileFilter: Second argument" fileset);
_fileFilter predicate path;
/*
The file set containing all files that are in both of two given file sets.

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@ -786,9 +786,9 @@ rec {
_differenceTree (path + "/${name}") lhsValue (rhs.${name} or null)
) (_directoryEntries path lhs);
# Filters all files in a file set based on a predicate
# Type: ({ name, type, ... } -> Bool) -> FileSet -> FileSet
_fileFilter = predicate: fileset:
# Filters all files in a path based on a predicate
# Type: ({ name, type, ... } -> Bool) -> Path -> FileSet
_fileFilter = predicate: root:
let
# Check the predicate for a single file
# Type: String -> String -> filesetTree
@ -807,19 +807,22 @@ rec {
# Check the predicate for all files in a directory
# Type: Path -> filesetTree
fromDir = path: tree:
mapAttrs (name: subtree:
if isAttrs subtree || subtree == "directory" then
fromDir (path + "/${name}") subtree
else if subtree == null then
null
fromDir = path:
mapAttrs (name: type:
if type == "directory" then
fromDir (path + "/${name}")
else
fromFile name subtree
) (_directoryEntries path tree);
fromFile name type
) (readDir path);
rootType = pathType root;
in
if fileset._internalIsEmptyWithoutBase then
_emptyWithoutBase
if rootType == "directory" then
_create root (fromDir root)
else
_create fileset._internalBase
(fromDir fileset._internalBase fileset._internalTree);
# Single files are turned into a directory containing that file or nothing.
_create (dirOf root) {
${baseNameOf root} =
fromFile (baseNameOf root) rootType;
};
}

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@ -813,14 +813,15 @@ checkFileset 'difference ./. ./b'
# The first argument needs to be a function
expectFailure 'fileFilter null (abort "this is not needed")' 'lib.fileset.fileFilter: First argument is of type null, but it should be a function instead.'
# The second argument can be a file set or an existing path
expectFailure 'fileFilter (file: abort "this is not needed") null' 'lib.fileset.fileFilter: Second argument is of type null, but it should be a file set or a path instead.'
# The second argument needs to be an existing path
expectFailure 'fileFilter (file: abort "this is not needed") _emptyWithoutBase' 'lib.fileset.fileFilter: Second argument is a file set, but it should be a path instead.
\s*If you need to filter files in a file set, use `intersection fileset \(fileFilter pred \./\.\)` instead.'
expectFailure 'fileFilter (file: abort "this is not needed") null' 'lib.fileset.fileFilter: Second argument is of type null, but it should be a path instead.'
expectFailure 'fileFilter (file: abort "this is not needed") ./a' 'lib.fileset.fileFilter: Second argument \('"$work"'/a\) is a path that does not exist.'
# The predicate is not called when there's no files
tree=()
checkFileset 'fileFilter (file: abort "this is not needed") ./.'
checkFileset 'fileFilter (file: abort "this is not needed") _emptyWithoutBase'
# The predicate must be able to handle extra attributes
touch a
@ -882,14 +883,6 @@ checkFileset 'union ./c/a (fileFilter (file: assert file.name != "a"; true) ./.)
# but here we need to use ./c
checkFileset 'union (fileFilter (file: assert file.name != "a"; true) ./.) ./c'
# Also lazy, the filter isn't called on a filtered out path
tree=(
[a]=1
[b]=0
[c]=0
)
checkFileset 'fileFilter (file: assert file.name != "c"; file.name == "a") (difference ./. ./c)'
# Make sure single files are filtered correctly
tree=(
[a]=1