[Scons-users] Bash + os.environ is an evil

[Gary Oberbrunner]

On Fri, Apr 4, 2014 at 9:45 AM, Paweł Tomulik <ptomulik at meil.pw.edu.pl>wrote:


> Not really a question, just want to share my today's experience.

>

> This code

>

> import os

> env = Environment(ENV = os.environ)

>

> can cause real headache. Especially if SCons is started under bash.

>

> It appears, that os.environ may contain bash functions, for example:

>

> {  'module' : "() { eval `/usr/bin/modulecmd bash \$*`\n}", ... }

>

> The effect is, that SCons executes these functions occasionally when

> executing its actions, especially when configuring with SConf.

>

> ...



Hi Paweł; that's the first I've ever heard of shell functions going into
the shell environment, but I can see it's possible.  They are just strings
of course, but some shells may treat them specially.

However, SCons should NEVER execute those!  It should treat all os.environ
pairs as simple key:value pairs.  Perhaps you mean that when you export
this environment to a subshell and the subshell tries to exec 'module',
_it_ executes the offending shell function?  That of course would be
possible (though amazingly annoying IMHO, unless someone was depending on
it).

-- 
Gary
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