Propagate custom cfg directives to rustdoc and doctests

[gkoz]

Fixes #1980

[rust-highfive]

r? @wycats

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[gkoz]

r? @alexcrichton

[alexcrichton]

You'll want to do a hash lookup here to ensure that you're doing the right thing in a cross-compilation scenario. Right now this ignores the Kind which is an important distinction for target/host compiles.

The Kind to use in the key should be present in unit.kind right before the work is created, and that should do the trick!

[gkoz]

Thanks, I wasn't sure whether the kind mattered here.

[alexcrichton]

Awesome, thanks @gkoz!

[gkoz]

Updated for both comments.

[gkoz]

@alexcrichton looks like you don't have `Rolling builds" enabled in appveyor project settings. Because of this it doesn't stop building stale commits promptly and takes longer to get to the current ones.

[alexcrichton]

This'll actually want to drop the lock ASAP instead of holding it over the entire call to rustdoc

[gkoz]

Heh, right 😳

[gkoz]

Would you put it like this then? It's a lot on one line and not very obvious that the lock will get released.

        if let Some(output) = build_state.outputs.lock().unwrap().get(&key) {
            for cfg in output.cfgs.iter() {
                rustdoc.arg("--cfg").arg(cfg);
            }
        }

[gkoz]

But the alternative is putting everything into an explicit block, not very nice looking either. Or explicit drop perhaps.

[gkoz]

Or

        if let Ok(outputs) = build_state.outputs.lock() {
            if let Some(output) = outputs.get(&key) {
                for cfg in output.cfgs.iter() {
                    rustdoc.arg("--cfg").arg(cfg);
                }
            }
        }
        /*
        else {
            return_an_error?
        }
        */

[alexcrichton]

Whoa, I had no idea that option existed! I've turned it on now

[gkoz]

I went with the more concise version giving the lock up after iterating over cfgs. At least I believe its lifetime will now be limited to the if let block.

[alexcrichton]

@bors: r+ 807da6b

Thanks!

[bors]

⌛ Testing commit 807da6b with merge 1dc1865...

[bors]

☀️ Test successful - cargo-linux-32, cargo-linux-64, cargo-mac-32, cargo-mac-64, cargo-win-gnu-32, cargo-win-gnu-64, cargo-win-msvc-32, cargo-win-msvc-64