This patch makes two changes.
(1) It memoizes the computation of dependsOnOld.
(2) It replaces rewrittenDerivations with a similar memoized table rewriteMemo.
This prevents the entire tree of run-time dependencies from being traversed and instead only traverses the graph of run-time dependencies.
In the case of deep dependency changes (such as changing one's bash version for an entire NixOS system) this can lead to an exponential speedup in processing time
because shared dependencies are no longer traversed multiple times.
This patch isn't quite derivation-per-derivation equivalent to the original computation.
There are two immaterial differences.
(1) The previous version would always call upon sed to replace oldDependency with newDependency even when the store object being updated doesn't directly depend on
oldDependency.
The new version only replaceds oldDependency with newDependency when the store object being updated actually directly depends on oldDependency (which means there is
actually a hash to replace).
(2) The previous version would list the old store object as a source input of the new store object, *except* for the root derivation being updated. Because the
root derivation being updated has its actual derivation avaiable the previous verions would make the updated root derivation depend on the old derivation as a
derivation input instead of a source input.
The new version always lists the old store object as a source input, including the root derivation.
We still need this because some clang-based packages depend on
it. (The sysroot filtering was originally done by clang-wrapper's
ld-wrapper, but we merged the ld-wrappers in
a4f9b9c8b5ec9ef106671ffdf93e0059835d0ec1.)
http://hydra.nixos.org/build/13906922
Fixes a regression on OS X introduced by f83af95.
Don't use --tmpdir for mktemp, because that flag doesn't exist on OS X.
However, using -t is deprecated in GNU coreutils, so as suggested by
@ip1981 we're now using parameter expansion on ${TMPDIR:-/tmp} to
provide /tmp as a fallback if TMPDIR is not set and use it instead.
Also use this approach for nix-prefetch-cvs now in order to stay
consistent.
Reported-by: Vladimir Kirillov <proger@wilab.org.ua>
Tested-by: Igor Pashev <pashev.igor@gmail.com>
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Instead of relying on $$ to not collide with an existing path.
Quoting the Bash manual about $$:
> Expands to the process ID of the shell. In a () subshell, it expands
> to the process ID of the current shell, not the subshell.
So, this is different from $BASHPID:
> Expands to the process ID of the current bash process. This differs
> from $$ under certain circumstances, such as subshells that do not
> require bash to be re-initialized.
But even $BASHPID is prone to race conditions if the process IDs wrap
around, so to be on the safe side, we're using mktemp here.
Closes#3784.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
For now, we don't NATIVE_SYSTEM_HEADER_DIR because it breaks the
build. However, it points to Glibc in the Nix store (not /usr/include)
so it's kind of okay.
