scons messes up the environment and removes ${prefix}/bin from $PATH

[jeremyhu (Jeremy Huddleston Sequoia)]

scons messes up the environment in processes it spawns.

Most horrifically, it messes up $PATH, removing ${prefix}/bin. This can cause it to not find the correct tools when it does things like executing install-name-tool to workaround other horrific design decisions in the build system (specifically, not setting the dylib id at link time).

---

I verified that the environment was this in pre_destdir:

TMPDIR=/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/.tmp
NO_PROXY=*.local,169.254/16
USER=root
CCACHE_DIR=/opt/local/var/macports/build/.ccache
COLUMNS=164
PATH=/opt/local/bin:/opt/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin
PWD=/opt/local/var/macports
LANG=en_US.UTF-8
LINES=45
SHLVL=1
HOME=/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/.home
_=/usr/bin/env

But when scons executed install-name-tool, it picked it up from /usr/bin instead of /opt/local/bin, and this was the path in that process (I replaced /usr/bin/install-name-tool with a shell script to verify this):

PATH=/opt/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin
_=/usr/bin/env
PWD=/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/serf-1.3.4
PATHOSX=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin
SHLVL=2

This pretty much prevents the scons build system from being used with modern toolchains on older systems because older install-name-tool will fail like:

scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
Install file: "libserf-1.a" as "/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/destroot/opt/local/lib/libserf-1.a"
Install file: "libserf-1.1.3.4.dylib" as "/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/destroot/opt/local/lib/libserf-1.1.3.4.dylib"
install_name_tool -id /opt/local/lib/libserf-1.dylib /opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/destroot/opt/local/lib/libserf-1.1.3.4.dylib
install_name_tool: for architecture x86_64 object: /opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_www_serf1/serf1/work/destroot/opt/local/lib/libserf-1.1.3.4.dylib malformed object (unknown load command 7)

[jeremyhu (Jeremy Huddleston Sequoia)]

Some of this mess is the fault of serf1's Sconstruct file, but the PATH issue seems to be from scons itself and not serf-specific bits.

[larryv (Lawrence Velázquez)]

I’ve updated scons to 2.5.1. Is this still an issue?

[ryandesign (Ryan Carsten Schmidt)]

It is an intentional misfeature of scons that it does not inherit the environment of the calling process. It is up to the author of each SConscript or SConstruct file to import the environment variables that they want to import.

​https://scons.org/doc/latest/HTML/scons-user/ch07s03.html

For this any many other reasons, I recommend all projects move from scons to any other build system.