Merge pull request #260265 from tweag/fileset.fileFilter

`lib.fileset.fileFilter`: init
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Robert Hensing 2023-10-24 11:29:57 +02:00 committed by GitHub
commit 185acbce7d
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3 changed files with 144 additions and 0 deletions

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@ -6,6 +6,7 @@ let
_coerceMany
_toSourceFilter
_unionMany
_fileFilter
_printFileset
_intersection
;
@ -41,6 +42,7 @@ let
;
inherit (lib.trivial)
isFunction
pipe
;
@ -278,6 +280,55 @@ If a directory does not recursively contain any file, it is omitted from the sto
_unionMany
];
/*
Filter a file set to only contain files matching some predicate.
Type:
fileFilter ::
({
name :: String,
type :: String,
...
} -> Bool)
-> FileSet
-> FileSet
Example:
# Include all regular `default.nix` files in the current directory
fileFilter (file: file.name == "default.nix") ./.
# Include all non-Nix files from the current directory
fileFilter (file: ! hasSuffix ".nix" file.name) ./.
# Include all files that start with a "." in the current directory
fileFilter (file: hasPrefix "." file.name) ./.
# Include all regular files (not symlinks or others) in the current directory
fileFilter (file: file.type == "regular")
*/
fileFilter =
/*
The predicate function to call on all files contained in given file set.
A file is included in the resulting file set if this function returns true for it.
This function is called with an attribute set containing these attributes:
- `name` (String): The name of the file
- `type` (String, one of `"regular"`, `"symlink"` or `"unknown"`): The type of the file.
This matches result of calling [`builtins.readFileType`](https://nixos.org/manual/nix/stable/language/builtins.html#builtins-readFileType) on the file's path.
Other attributes may be added in the future.
*/
predicate:
# The file set to filter based on the predicate function
fileset:
if ! isFunction predicate then
throw "lib.fileset.fileFilter: Expected the first argument to be a function, but it's a ${typeOf predicate} instead."
else
_fileFilter predicate
(_coerce "lib.fileset.fileFilter: second argument" fileset);
/*
The file set containing all files that are in both of two given file sets.
See also [Intersection (set theory)](https://en.wikipedia.org/wiki/Intersection_(set_theory)).

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@ -638,4 +638,30 @@ rec {
else
# In all other cases it's the rhs
rhs;
_fileFilter = predicate: fileset:
let
recurse = path: tree:
mapAttrs (name: subtree:
if isAttrs subtree || subtree == "directory" then
recurse (path + "/${name}") subtree
else if
predicate {
inherit name;
type = subtree;
# To ensure forwards compatibility with more arguments being added in the future,
# adding an attribute which can't be deconstructed :)
"lib.fileset.fileFilter: The predicate function passed as the first argument must be able to handle extra attributes for future compatibility. If you're using `{ name, file }:`, use `{ name, file, ... }:` instead." = null;
}
then
subtree
else
null
) (_directoryEntries path tree);
in
if fileset._internalIsEmptyWithoutBase then
_emptyWithoutBase
else
_create fileset._internalBase
(recurse fileset._internalBase fileset._internalTree);
}

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@ -678,6 +678,73 @@ tree=(
checkFileset 'intersection (unions [ ./a/b ./c/d ./c/e ]) (unions [ ./a ./c/d/f ./c/e ])'
## File filter
# 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
expectFailure 'toSource { root = ./.; fileset = fileFilter ({ name, type }: true) ./.; }' 'called with unexpected argument '\''"lib.fileset.fileFilter: The predicate function passed as the first argument must be able to handle extra attributes for future compatibility. If you'\''re using `\{ name, file \}:`, use `\{ name, file, ... \}:` instead."'\'
rm -rf -- *
# .name is the name, and it works correctly, even recursively
tree=(
[a]=1
[b]=0
[c/a]=1
[c/b]=0
[d/c/a]=1
[d/c/b]=0
)
checkFileset 'fileFilter (file: file.name == "a") ./.'
tree=(
[a]=0
[b]=1
[c/a]=0
[c/b]=1
[d/c/a]=0
[d/c/b]=1
)
checkFileset 'fileFilter (file: file.name != "a") ./.'
# `.type` is the file type
mkdir d
touch d/a
ln -s d/b d/b
mkfifo d/c
expectEqual \
'toSource { root = ./.; fileset = fileFilter (file: file.type == "regular") ./.; }' \
'toSource { root = ./.; fileset = ./d/a; }'
expectEqual \
'toSource { root = ./.; fileset = fileFilter (file: file.type == "symlink") ./.; }' \
'toSource { root = ./.; fileset = ./d/b; }'
expectEqual \
'toSource { root = ./.; fileset = fileFilter (file: file.type == "unknown") ./.; }' \
'toSource { root = ./.; fileset = ./d/c; }'
expectEqual \
'toSource { root = ./.; fileset = fileFilter (file: file.type != "regular") ./.; }' \
'toSource { root = ./.; fileset = union ./d/b ./d/c; }'
expectEqual \
'toSource { root = ./.; fileset = fileFilter (file: file.type != "symlink") ./.; }' \
'toSource { root = ./.; fileset = union ./d/a ./d/c; }'
expectEqual \
'toSource { root = ./.; fileset = fileFilter (file: file.type != "unknown") ./.; }' \
'toSource { root = ./.; fileset = union ./d/a ./d/b; }'
rm -rf -- *
# It's lazy
tree=(
[b]=1
[c/a]=1
)
# Note that union evaluates the first argument first if necessary, that's why we can use ./c/a here
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'
## Tracing
# The second trace argument is returned