Auto merge of #5389 - matklad:one-hard-cs-problem, r=alexcrichton

One hard cs problem

Closes #5313

r? @alexcrichton

Note that, due to the first commit, this still gives us all the benefits of #5249: if RUSTFLAGS is empty, we will run only a single rustc process, even if we can't cache it across different cargo invocations.

Author: bors

src/cargo/core/compiler/context/mod.rs

@@ -129,17 +129,8 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         let (host_info, target_info) = {
             let _p = profile::start("Context::probe_target_info");
             debug!("probe_target_info");
-            let host_target_same = match build_config.requested_target {
-                Some(ref s) if s != &build_config.host_triple() => false,
-                _ => true,
-            };
-
             let host_info = TargetInfo::new(config, &build_config, Kind::Host)?;
-            let target_info = if host_target_same {
-                host_info.clone()
-            } else {
-                TargetInfo::new(config, &build_config, Kind::Target)?
-            };
+            let target_info = TargetInfo::new(config, &build_config, Kind::Target)?;
             (host_info, target_info)
         };
 

src/cargo/core/package.rs

@@ -46,7 +46,7 @@ struct SerializedPackage<'a> {
     categories: &'a [String],
     keywords: &'a [String],
     readme: Option<&'a str>,
-    repository: Option<&'a str>
+    repository: Option<&'a str>,
 }
 
 impl ser::Serialize for Package {

src/cargo/core/resolver/mod.rs

@@ -68,7 +68,7 @@ use self::types::{RcVecIter, RegistryQueryer};
 
 pub use self::encode::{EncodableDependency, EncodablePackageId, EncodableResolve};
 pub use self::encode::{Metadata, WorkspaceResolve};
-pub use self::resolve::{Resolve, Deps, DepsNotReplaced};
+pub use self::resolve::{Deps, DepsNotReplaced, Resolve};
 pub use self::types::Method;
 
 mod context;

src/cargo/sources/registry/index.rs

@@ -150,7 +150,8 @@ impl<'cfg> RegistryIndex<'cfg> {
             links,
         } = serde_json::from_str(line)?;
         let pkgid = PackageId::new(&name, &vers, &self.source_id)?;
-        let deps = deps.into_iter().map(|dep| dep.into_dep(&self.source_id))
+        let deps = deps.into_iter()
+            .map(|dep| dep.into_dep(&self.source_id))
             .collect::<CargoResult<Vec<_>>>()?;
         let summary = Summary::new(pkgid, deps, features, links)?;
         let summary = summary.set_checksum(cksum.clone());

src/cargo/util/rustc.rs

@@ -154,19 +154,6 @@ impl Cache {
     }
 
     fn cached_output(&mut self, cmd: &ProcessBuilder) -> CargoResult<(String, String)> {
-        let calculate = || {
-            let output = cmd.exec_with_output()?;
-            let stdout = String::from_utf8(output.stdout)
-                .map_err(|_| internal("rustc didn't return utf8 output"))?;
-            let stderr = String::from_utf8(output.stderr)
-                .map_err(|_| internal("rustc didn't return utf8 output"))?;
-            Ok((stdout, stderr))
-        };
-        if self.cache_location.is_none() {
-            info!("rustc info uncached");
-            return calculate();
-        }
-
         let key = process_fingerprint(cmd);
         match self.data.outputs.entry(key) {
             Entry::Occupied(entry) => {
@@ -175,7 +162,12 @@ impl Cache {
             }
             Entry::Vacant(entry) => {
                 info!("rustc info cache miss");
-                let output = calculate()?;
+                let output = cmd.exec_with_output()?;
+                let stdout = String::from_utf8(output.stdout)
+                    .map_err(|_| internal("rustc didn't return utf8 output"))?;
+                let stderr = String::from_utf8(output.stderr)
+                    .map_err(|_| internal("rustc didn't return utf8 output"))?;
+                let output = (stdout, stderr);
                 entry.insert(output.clone());
                 self.dirty = true;
                 Ok(output)

tests/testsuite/cfg.rs

@@ -445,3 +445,48 @@ fn any_ok() {
         .build();
     assert_that(p.cargo("build").arg("-v"), execs().with_status(0));
 }
+
+// https://github.com/rust-lang/cargo/issues/5313
+#[test]
+#[cfg(all(target_arch = "x86_64", target_os = "linux"))]
+fn cfg_looks_at_rustflags_for_target() {
+    let p = project("foo")
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "a"
+            version = "0.0.1"
+            authors = []
+
+            [target.'cfg(with_b)'.dependencies]
+            b = { path = 'b' }
+        "#,
+        )
+        .file(
+            "src/main.rs",
+            r#"
+            #[cfg(with_b)]
+            extern crate b;
+
+            fn main() { b::foo(); }
+        "#,
+        )
+        .file(
+            "b/Cargo.toml",
+            r#"
+            [package]
+            name = "b"
+            version = "0.0.1"
+            authors = []
+        "#,
+        )
+        .file("b/src/lib.rs", "pub fn foo() {}")
+        .build();
+
+    assert_that(
+        p.cargo("build --target x86_64-unknown-linux-gnu")
+            .env("RUSTFLAGS", "--cfg with_b"),
+        execs().with_status(0),
+    );
+}

tests/testsuite/rustc_info_cache.rs

@@ -20,7 +20,6 @@ fn rustc_info_cache() {
 
     let miss = "[..] rustc info cache miss[..]";
     let hit = "[..]rustc info cache hit[..]";
-    let uncached = "[..]rustc info uncached[..]";
     let update = "[..]updated rustc info cache[..]";
 
     assert_that(
@@ -50,7 +49,6 @@ fn rustc_info_cache() {
         execs()
             .with_status(0)
             .with_stderr_contains("[..]rustc info cache disabled[..]")
-            .with_stderr_contains(uncached)
             .with_stderr_does_not_contain(update),
     );