Jeff King <peff@xxxxxxxx> writes:
> The actual prep_childenv() code looks like it would always do
> last-one-wins, so we should treat FOO as unset in that final case. But
> that only kicks in on non-Windows.
>
> On Windows we feed cmd->env straight to mingw_spawnvpe(). That ends up
> in make_environment_block(), which looks like it does something similar.
>
> It's too bad the prep code is not shared, since then we could probably
> just ask _it_ which deltas it applied.
Yeah, but that function does a lot more than computing delta.
It's primary point, which comes from ae25394b ("run-command: prepare
child environment before forking", 2017-04-19), is to create a full
copy of the environment, not just a series of putenv/unsetenv that
describes what gets changed, and that is done to avoid any
allocation after fork before exec in the child process.
I guess prep_childenv() could take an extra and optional string-list
to report what "deltas" it applied to the tracing machinery. I am
not sure if that is worth it, though.
