lib: Use Nix's static scope checking, fix error message, optimize

Nix can perform static scope checking, but whenever code is inside
a `with` expression, the analysis breaks down, because it can't
know statically what's in the attribute set whose attributes were
brought into scope. In those cases, Nix has to assume that
everything works out.

Except it doesnt. Removing `with` from lib/ revealed an undefined
variable in an error message.

If that doesn't convince you that we're better off without `with`,
I can tell you that this PR results in a 3% evaluation performance
improvement because Nix can look up local variables by index.
This adds up with applications like the module system.

Furthermore, removing `with` makes the binding site of each
variable obvious, which helps with comprehension.
This commit is contained in:
Robert Hensing
2020-10-22 13:46:47 +02:00
parent 5aa2a98dfa
commit afa6c51f27
9 changed files with 238 additions and 82 deletions
+55 -5
View File
@@ -1,12 +1,62 @@
# Definitions related to run-time type checking. Used in particular
# to type-check NixOS configurations.
{ lib }:
with lib.lists;
with lib.attrsets;
with lib.options;
with lib.trivial;
with lib.strings;
let
inherit (lib)
elem
flip
functionArgs
isAttrs
isBool
isDerivation
isFloat
isFunction
isInt
isList
isString
isStorePath
setFunctionArgs
toDerivation
toList
;
inherit (lib.lists)
all
concatLists
count
elemAt
filter
foldl'
head
imap1
last
length
tail
unique
;
inherit (lib.attrsets)
attrNames
filterAttrs
hasAttr
mapAttrs
optionalAttrs
zipAttrsWith
;
inherit (lib.options)
getFiles
getValues
mergeDefaultOption
mergeEqualOption
mergeOneOption
showFiles
showOption
;
inherit (lib.strings)
concatMapStringsSep
concatStringsSep
escapeNixString
isCoercibleToString
;
inherit (lib.modules) mergeDefinitions;
outer_types =