This is guaranteed to be safe. The tree can be a simple string if the
fileset is the same as the root, but the `or` takes care of that. In the
`or` case, the tree is guaranteed to fail the isAttrs check, and so even
though the index is invalid, it won't matter.
The stringLength check is equivalent at this point, but having to
actualy create the thunk for calling stringLength is likely slower than
just letting Nix handle the equality check.
The source filter runs on every path underneath the base directory, but
only on the few paths above it.
Reorder the prefix checks so the dominant below-the-base case does a
single substring + comparison instead of two, with an explicit branch
for the path being the base itself (which the previous first check also covered).
_normaliseTreeFilter strictly walks the entire file set tree on every
toSource call. File entries (null or a file type string) are already
normalised, so dispatch on the subtree inside the mapAttrs closure
instead of making a recursive call that immediately returns its
argument. This also avoids allocating an unused `path + "/${name}"`
argument thunk for every file.
This function runs once per directory node per union during lazy tree evaluation.
This makes it one of the hottest paths in lib.fileset for large trees.
It was measuared at ~9% of _total evaluation_ time in a very large monorepo.
This change is a 2-in-1:
- Return singleton lists directly to avoid rebuilding subtrees
- Use foldl instead of findFirstIndex
This is a hot path so the indexing arithmetic adds up.
- concrete types start with uppercase: Int, String, Bool, Derivation,
etc.
- type variables start with lowercase: a, b, etc.
- list:
- use `[x]` for homogeneous lists instead of `List x` or `[ x ]`
- use `List` for heterogeneous lists (not that common in `lib`)
- attr:
- use `AttrSet` for a generic attribute set type
- use `{ key1 :: Type1; key2 :: Type2; ... }` for adding signatures
for known attribute names and types
- use `{ key1 = value1; key2 = value2; ... }` for adding attributes
with known literals
- end with an ellipsis (`...`) if the set can contain unknown
attributes
- use `{ [String] :: x }` if all the attributes has the same type `x`
- prefer `Any` over `a` if the latter is not reused
After final improvements to the official formatter implementation,
this commit now performs the first treewide reformat of Nix files using it.
This is part of the implementation of RFC 166.
Only "inactive" files are reformatted, meaning only files that
aren't being touched by any PR with activity in the past 2 months.
This is to avoid conflicts for PRs that might soon be merged.
Later we can do a full treewide reformat to get the rest,
which should not cause as many conflicts.
A CI check has already been running for some time to ensure that new and
already-formatted files are formatted, so the files being reformatted here
should also stay formatted.
This commit was automatically created and can be verified using
nix-build a08b3a4d19.tar.gz \
--argstr baseRev b32a094368
result/bin/apply-formatting $NIXPKGS_PATH
The only reason shallow clones are not the default in
`builtins.fetchGit` is that `revCount` can't be provided when cloning a
shallow repository. However, `revCount` isn't used or exposed by
`lib.fileset`. Hence, allowing cloning shallow repositories makes
`gitTracked` more general without any drawbacks.
Co-authored-by: Silvan Mosberger <github@infinisil.com>
- Make fromSource's missing file error message more consistent with others,
and add a test for it
- Indent some function arguments
- Fix an internal type
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
Just minor changes like:
- Always using "X is a Y, but it should be Z"
- "X is a path that does not exist" rather than "X does not exist"
- Always using multi-line strings for errors
- Always quoting string-like values and not quoting path-like values
- But do quote filesystem roots. Even though they're paths, they might
be very small, good to have quotes to know the start/end
- Capitalise the first word
- Distinguish root vs filesystem root more
This does decrease performance unfortunately
Benchmarking expression toSource { root = ./.; fileset = ./.; }
Mean CPU time 0.103747 (σ = 0.012415) for 10 runs is 97.32181384964636% (σ = 16.34179537413021%) of the old value 0.106602 (σ = 0.0125571)
Statistic .envs.elements (205920) is 105.5842% (+10891) of the old value 195029
Statistic .gc.totalBytes (20247696) is 101.7495% (+348160) of the old value 19899536
Statistic .nrThunks (134824) is 108.7878% (+10891) of the old value 123933
Statistic .symbols.number (996) is 100.1005% (+1) of the old value 995
Statistic .values.number (275238) is 104.1199% (+10891) of the old value 264347
