It turns out that cargo implicitly depends on rustc at runtime: even
`cargo help` will fail if rustc is not in the PATH.
This means that we need to wrap the cargo binary to add rustc to PATH.
However, I have opted into doing something slightly unusual: instead of
tying down a specific cargo to use a specific rustc (i.e., wrap cargo so
that "${rustc}/bin" is prefixed into PATH), instead I'm adding the rustc
used to build cargo as a fallback rust compiler (i.e., wrap cargo so
that "${rustc}/bin" is suffixed into PATH). This means that cargo will
prefer to use a rust compiler that is in the default path, but fallback
into the one used to build cargo only if there wasn't any rust compiler
in the default path.
The reason I'm doing this is that otherwise it could cause unexpected
effects. For example, if you had a build environment with the
rustcMaster and cargo derivations, you would expect cargo to use
rustcMaster to compile your project (since rustcMaster would be the only
compiler available in $PATH), but this wouldn't happen if we tied down
cargo to use the rustc that was used to compile it (because the default
cargo derivation gets compiled with the stable rust compiler).
That said, I have slightly modified makeRustPlatform so that a rust
platform will always use the rust compiler that was used to build cargo,
because this prevents mistakenly depending on two different versions of
the rust compiler (stable and unstable) in the same rust platform,
something which is usually undesirable.
Fixes #11053
The fetch-cargo-deps script is written in bash syntax, but it
erroneously ran under the /bin/sh interpreter.
This wasn't noticed because /bin/sh is actually bash in NixOS, but on
some other systems this is not true.
While debugging an issue with running NixOps tests, I found out that the
output from debClosureGenerator is not deterministic.
The reason behind this is the way how Provides and Replaces fields are
handled. I haven't yet found out what's the exact issue, but so far
packages "Provides" are more or less picked at random.
So, running the NixOps Hetzner tests we get either mawk, original-awk or
gawk altering on every invocation.
While for the test it isn't poisionous whether wi have mawk or gawk,
having original-awk certainly is, because live-build only works with
mawk or gawk.
The best solution would obviously be to make debClosureGenerator
deterministic, but in the case of "Provides: awk", we can safely pick
mawk by default, because the latter has a "Priority: required" in its
package description.
This also has the advantage that we can safely cherry-pick this to
release-15.09 because it's very unlikely that we'll break the
debClosureGenerator by adding a dependency to commonDebPackages.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
This should avoid accidential expansion of variables, i.e. in
"export PATH=/some/path:$PATH"
$PATH would have been expanded in the environment builder!
