The code of `lib.closePropagation` was internally using a
recursion on the dependencies and returns all the derivation directly or
indirectly referenced by buildInputs.
`lib.closeProgation` is implemented in pure nix and uses an unique
function for list which is quadratic and does "true" equality, which
needs deep set comparison.
Instead, we use the `builtins.genericClosure` which is implemented as a
builtin and uses a more efficient sorting feature.
Note that `genericClosure` needs a `key` to discriminate the values, we
used the `outPath` which is unique and orderable.
On benchmarks, it performs up to 15x time faster on a benchmark related
to haskellPackages.ghcWithPackages.
The previous hash was too short and caused evaluation-time errors like:
invalid SRI hash 'sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA='
Additionally, since the fact that this is broken implies that nobody
could have been using it, "SRI" is a bit of a vague and obscure term,
`fakeSriHash` would be somewhat of a mouthful, and the relevant fetcher
parameters are just called `hash`, rename it to `fakeHash`.
Fake hashes can be used as placeholders for all the places, where
Nix expression requires a hash, but we don't yet have one.
This should be more convenient than following:
- echo|sha256sum, copy into clipboard, go to editor, paste into previously
edited place
- search nixpkgs for a random package, copy it's hash to cliboard, go to
editor, paste into previously edited place
Nix can add support for these fake hashes. In that case printed error should contain
only 1 hash, so no more problem "which of two hashes from error should I use?"
Idea by irc:Synthetica
Among other things, this will allow *2nix tools to output plain data
while still being composable with the traditional
callPackage/.override interfaces.
This does break the API of being able to import any lib file and get
its libs, however I'm not sure people did this.
I made this while exploring being able to swap out docFn with a stub
in #2305, to avoid functor performance problems. I don't know if that
is going to move forward (or if it is a problem or not,) but after
doing all this work figured I'd put it up anyway :)
Two notable advantages to this approach:
1. when a lib inherits another lib's functions, it doesn't
automatically get put in to the scope of lib
2. when a lib implements a new obscure functions, it doesn't
automatically get put in to the scope of lib
Using the test script (later in this commit) I got the following diff
on the API:
+ diff master fixed-lib
11764a11765,11766
> .types.defaultFunctor
> .types.defaultTypeMerge
11774a11777,11778
> .types.isOptionType
> .types.isType
11781a11786
> .types.mkOptionType
11788a11794
> .types.setType
11795a11802
> .types.types
This means that this commit _adds_ to the API, however I can't find a
way to fix these last remaining discrepancies. At least none are
_removed_.
Test script (run with nix-repl in the PATH):
#!/bin/sh
set -eux
repl() {
suff=${1:-}
echo "(import ./lib)$suff" \
| nix-repl 2>&1
}
attrs_to_check() {
repl "${1:-}" \
| tr ';' $'\n' \
| grep "\.\.\." \
| cut -d' ' -f2 \
| sed -e "s/^/${1:-}./" \
| sort
}
summ() {
repl "${1:-}" \
| tr ' ' $'\n' \
| sort \
| uniq
}
deep_summ() {
suff="${1:-}"
depth="${2:-4}"
depth=$((depth - 1))
summ "$suff"
for attr in $(attrs_to_check "$suff" | grep -v "types.types"); do
if [ $depth -eq 0 ]; then
summ "$attr" | sed -e "s/^/$attr./"
else
deep_summ "$attr" "$depth" | sed -e "s/^/$attr./"
fi
done
}
(
cd nixpkgs
#git add .
#git commit -m "Auto-commit, sorry" || true
git checkout fixed-lib
deep_summ > ../fixed-lib
git checkout master
deep_summ > ../master
)
if diff master fixed-lib; then
echo "SHALLOW MATCH!"
fi
(
cd nixpkgs
git checkout fixed-lib
repl .types
)
* lib: introduce imap0, imap1
For historical reasons, imap starts counting at 1 and it's not
consistent with the rest of the lib.
So for now we split imap into imap0 that starts counting at zero and
imap1 that starts counting at 1. And imap is marked as deprecated.
See c71e2d4235 (commitcomment-21873221)
* replace uses of lib.imap
* lib: move imap to deprecated.nix
Nix style seems to have settled on not using spaces between bound
variable names and the lambda : so I also tried to make those somewhat
more consistent throughout.
It's unused, and also a bad idea: because it recursively recomputes
every function argument and there is no sharing, you can get an
exponential (?) blowup in evaluation time. For example, evaluating
‘linuxPackages.kernel’ takes 0.09s and ~13 MiB, but evaluating
‘linuxPackages.kernel.deepOverride {}’ takes 3.6s and ~305 MiB.
