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doc/haskell: don't use lib.recursiveUpdate in overlays

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`lib.recursiveUpdate` indiscriminately recurses into all attribute sets,
also into derivations. This means that it is possible that evaluating a
derivation in the final haskell package set can cause something in
`prev.haskell` to be forced by `recursiveUpdate`, potentially causing an
evaluation error that should not happen.

It can be fixed using a well-crafted predicate for
`lib.recursiveUpdateUntil`, but most robust is just explicitly writing
out the desired merging manually.
This commit is contained in:
sternenseemann 2024-01-31 19:14:24 +01:00
parent 82ee069492
commit 571a07d774
1 changed files with 30 additions and 26 deletions
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56
doc/languages-frameworks/haskell.section.md
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@ -1229,10 +1229,12 @@ in
in in
{ {
haskell = lib.recursiveUpdate prev.haskell { haskell = prev.haskell // {
compiler.${ghcName} = prev.haskell.compiler.${ghcName}.override { compiler = prev.haskell.compiler // {
# Unfortunately, the GHC setting is named differently for historical reasons ${ghcName} = prev.haskell.compiler.${ghcName}.override {
enableProfiledLibs = enableProfiling; # Unfortunately, the GHC setting is named differently for historical reasons
enableProfiledLibs = enableProfiling;
};
}; };
}; };
}) })
@ -1244,31 +1246,33 @@ in
in in
{ {
haskell = lib.recursiveUpdate prev.haskell { haskell = prev.haskell // {
packages.${ghcName} = prev.haskell.packages.${ghcName}.override { packages = prev.haskell.packages // {
overrides = hfinal: hprev: { ${ghcName} = prev.haskell.packages.${ghcName}.override {
mkDerivation = args: hprev.mkDerivation (args // { overrides = hfinal: hprev: {
# Since we are forcing our ideas upon mkDerivation, this change will mkDerivation = args: hprev.mkDerivation (args // {
# affect every package in the package set. # Since we are forcing our ideas upon mkDerivation, this change will
enableLibraryProfiling = enableProfiling; # affect every package in the package set.
enableLibraryProfiling = enableProfiling;
# To actually use profiling on an executable, executable profiling # To actually use profiling on an executable, executable profiling
# needs to be enabled for the executable you want to profile. You # needs to be enabled for the executable you want to profile. You
# can either do this globally or… # can either do this globally or…
enableExecutableProfiling = enableProfiling; enableExecutableProfiling = enableProfiling;
}); });
# …only for the package that contains an executable you want to profile. # …only for the package that contains an executable you want to profile.
# That saves on unnecessary rebuilds for packages that you only depend # That saves on unnecessary rebuilds for packages that you only depend
# on for their library, but also contain executables (e.g. pandoc). # on for their library, but also contain executables (e.g. pandoc).
my-executable = haskellLib.enableExecutableProfiling hprev.my-executable; my-executable = haskellLib.enableExecutableProfiling hprev.my-executable;
# If you are disabling profiling to save on build time, but want to # If you are disabling profiling to save on build time, but want to
# retain the ability to substitute from the binary cache. Drop the # retain the ability to substitute from the binary cache. Drop the
# override for mkDerivation above and instead have an override like # override for mkDerivation above and instead have an override like
# this for the specific packages you are building locally and want # this for the specific packages you are building locally and want
# to make cheaper to build. # to make cheaper to build.
my-library = haskellLib.disableLibraryProfiling hprev.my-library; my-library = haskellLib.disableLibraryProfiling hprev.my-library;
};
}; };
}; };
}; };