From 233205c4646e4d1e62ef4da15bf143008945060c Mon Sep 17 00:00:00 2001
From: Mateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>
Date: Thu, 3 Nov 2022 14:49:24 +0900
Subject: [PATCH] rustBuildCrate: properly handle cargo env pragmas with spaces
There are two problems: first that we end up splitting on spaces in the
loop. Even when that is fixed, we still would split on spaces in the
`export` inside the loop. We need to guard against both.
Fixes #199298
Confirmed that it fixes the case mentioned in the ticket:
```console
[nix-develop]$ $(nix-build -I nixpkgs=/home/shana/programming/nixpkgs Cargo.nix -A rootCrate.build --no-out-link)/bin/nix-rustc-env-escape-repro
Expecting three words, got: first second third
```
I think this is going to cause a rebuild of every Rust package even if
they were unaffected, not much we can do here.
---
.../rust/build-rust-crate/configure-crate.nix | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/pkgs/build-support/rust/build-rust-crate/configure-crate.nix b/pkgs/build-support/rust/build-rust-crate/configure-crate.nix
index 5129777c9d51..473a91f9ce07 100644
--- a/pkgs/build-support/rust/build-rust-crate/configure-crate.nix
+++ b/pkgs/build-support/rust/build-rust-crate/configure-crate.nix
@@ -189,9 +189,21 @@ in ''
EXTRA_LINK=$(sed -n "s/^cargo:rustc-link-lib=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ')
EXTRA_LINK_SEARCH=$(sed -n "s/^cargo:rustc-link-search=\(.*\)/\1/p" target/build/${crateName}.opt | tr '\n' ' ' | sort -u)
+ # We want to read part of every line that has cargo:rustc-env= prefix and
+ # export it as environment variables. This turns out tricky if the lines
+ # have spaces: we can't wrap the command in double quotes as that captures
+ # all the lines in single output. We can't use while read loop because
+ # exporting from inside of it doesn't make it to the outside scope. We
+ # can't use xargs as export is a built-in and does not work from it. As a
+ # last resort then, we change the IFS so that the for loop does not split
+ # on spaces and reset it after we are done. See ticket #199298.
+ #
+ _OLDIFS="$IFS"
+ IFS=$'\n'
for env in $(sed -n "s/^cargo:rustc-env=\(.*\)/\1/p" target/build/${crateName}.opt); do
- export $env
+ export "$env"
done
+ IFS="$_OLDIFS"
CRATENAME=$(echo ${crateName} | sed -e "s/\(.*\)-sys$/\U\1/" -e "s/-/_/g")
grep -P "^cargo:(?!(rustc-|warning=|rerun-if-changed=|rerun-if-env-changed))" target/build/${crateName}.opt \