Auto merge of #4469 - nipunn1313:workspace_features, r=alexcrichton

Hashed dependencies of metadata into the metadata of a lib

This fixes one part of #3620. To my understanding, the more fundamental fix is more challenging

src/cargo/ops/cargo_rustc/context.rs

@@ -40,6 +40,7 @@ pub struct Context<'a, 'cfg: 'a> {
     pub compilation: Compilation<'cfg>,
     pub packages: &'a PackageSet<'cfg>,
     pub build_state: Arc<BuildState>,
+    pub build_script_overridden: HashSet<(PackageId, Kind)>,
     pub build_explicit_deps: HashMap<Unit<'a>, BuildDeps>,
     pub fingerprints: HashMap<Unit<'a>, Arc<Fingerprint>>,
     pub compiled: HashSet<Unit<'a>>,
@@ -55,7 +56,9 @@ pub struct Context<'a, 'cfg: 'a> {
     host_info: TargetInfo,
     profiles: &'a Profiles,
     incremental_enabled: bool,
+
     target_filenames: HashMap<Unit<'a>, Arc<Vec<(PathBuf, Option<PathBuf>, bool)>>>,
+    target_metadatas: HashMap<Unit<'a>, Option<Metadata>>,
 }
 
 #[derive(Clone, Default)]
@@ -82,7 +85,7 @@ impl TargetInfo {
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Hash, Eq, PartialEq, Ord, PartialOrd)]
 pub struct Metadata(u64);
 
 impl<'a, 'cfg> Context<'a, 'cfg> {
@@ -154,7 +157,11 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
             used_in_plugin: HashSet::new(),
             incremental_enabled: incremental_enabled,
             jobserver: jobserver,
+            build_script_overridden: HashSet::new(),
+
+            // TODO: Pre-Calculate these with a topo-sort, rather than lazy-calculating
             target_filenames: HashMap::new(),
+            target_metadatas: HashMap::new(),
         })
     }
 
@@ -362,21 +369,21 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
 
     /// Returns the directory for the specified unit where fingerprint
     /// information is stored.
-    pub fn fingerprint_dir(&mut self, unit: &Unit) -> PathBuf {
+    pub fn fingerprint_dir(&mut self, unit: &Unit<'a>) -> PathBuf {
         let dir = self.pkg_dir(unit);
         self.layout(unit.kind).fingerprint().join(dir)
     }
 
     /// Returns the appropriate directory layout for either a plugin or not.
-    pub fn build_script_dir(&mut self, unit: &Unit) -> PathBuf {
+    pub fn build_script_dir(&mut self, unit: &Unit<'a>) -> PathBuf {
         assert!(unit.target.is_custom_build());
         assert!(!unit.profile.run_custom_build);
         let dir = self.pkg_dir(unit);
         self.layout(Kind::Host).build().join(dir)
     }
 
     /// Returns the appropriate directory layout for either a plugin or not.
-    pub fn build_script_out_dir(&mut self, unit: &Unit) -> PathBuf {
+    pub fn build_script_out_dir(&mut self, unit: &Unit<'a>) -> PathBuf {
         assert!(unit.target.is_custom_build());
         assert!(unit.profile.run_custom_build);
         let dir = self.pkg_dir(unit);
@@ -394,7 +401,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
 
     /// Returns the appropriate output directory for the specified package and
     /// target.
-    pub fn out_dir(&mut self, unit: &Unit) -> PathBuf {
+    pub fn out_dir(&mut self, unit: &Unit<'a>) -> PathBuf {
         if unit.profile.doc {
             self.layout(unit.kind).root().parent().unwrap().join("doc")
         } else if unit.target.is_custom_build() {
@@ -406,7 +413,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         }
     }
 
-    fn pkg_dir(&mut self, unit: &Unit) -> String {
+    fn pkg_dir(&mut self, unit: &Unit<'a>) -> String {
         let name = unit.pkg.package_id().name();
         match self.target_metadata(unit) {
             Some(meta) => format!("{}-{}", name, meta),
@@ -440,7 +447,17 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
     /// We build to the path: "{filename}-{target_metadata}"
     /// We use a linking step to link/copy to a predictable filename
     /// like `target/debug/libfoo.{a,so,rlib}` and such.
-    pub fn target_metadata(&mut self, unit: &Unit) -> Option<Metadata> {
+    pub fn target_metadata(&mut self, unit: &Unit<'a>) -> Option<Metadata> {
+        if let Some(cache) = self.target_metadatas.get(unit) {
+            return cache.clone()
+        }
+
+        let metadata = self.calc_target_metadata(unit);
+        self.target_metadatas.insert(*unit, metadata.clone());
+        metadata
+    }
+
+    fn calc_target_metadata(&mut self, unit: &Unit<'a>) -> Option<Metadata> {
         // No metadata for dylibs because of a couple issues
         // - OSX encodes the dylib name in the executable
         // - Windows rustc multiple files of which we can't easily link all of them
@@ -483,6 +500,15 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         // when changing feature sets each lib is separately cached.
         self.resolve.features_sorted(unit.pkg.package_id()).hash(&mut hasher);
 
+        // Mix in the target-metadata of all the dependencies of this target
+        if let Ok(deps) = self.dep_targets(unit) {
+            let mut deps_metadata = deps.into_iter().map(|dep_unit| {
+                self.target_metadata(&dep_unit)
+            }).collect::<Vec<_>>();
+            deps_metadata.sort();
+            deps_metadata.hash(&mut hasher);
+        }
+
         // Throw in the profile we're compiling with. This helps caching
         // panic=abort and panic=unwind artifacts, additionally with various
         // settings like debuginfo and whatnot.
@@ -512,7 +538,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
     }
 
     /// Returns the file stem for a given target/profile combo (with metadata)
-    pub fn file_stem(&mut self, unit: &Unit) -> String {
+    pub fn file_stem(&mut self, unit: &Unit<'a>) -> String {
         match self.target_metadata(unit) {
             Some(ref metadata) => format!("{}-{}", unit.target.crate_name(),
                                           metadata),
@@ -537,7 +563,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
 
     /// Returns an Option because in some cases we don't want to link
     /// (eg a dependent lib)
-    pub fn link_stem(&mut self, unit: &Unit) -> Option<(PathBuf, String)> {
+    pub fn link_stem(&mut self, unit: &Unit<'a>) -> Option<(PathBuf, String)> {
         let src_dir = self.out_dir(unit);
         let bin_stem = self.bin_stem(unit);
         let file_stem = self.file_stem(unit);
@@ -578,6 +604,15 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
             return Ok(cache.clone())
         }
 
+        let result = self.calc_target_filenames(unit);
+        if let Ok(ref ret) = result {
+            self.target_filenames.insert(*unit, ret.clone());
+        }
+        result
+    }
+
+    fn calc_target_filenames(&mut self, unit: &Unit<'a>)
+                            -> CargoResult<Arc<Vec<(PathBuf, Option<PathBuf>, bool)>>> {
         let out_dir = self.out_dir(unit);
         let stem = self.file_stem(unit);
         let link_stem = self.link_stem(unit);
@@ -659,9 +694,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         }
         info!("Target filenames: {:?}", ret);
 
-        let ret = Arc::new(ret);
-        self.target_filenames.insert(*unit, ret.clone());
-        Ok(ret)
+        Ok(Arc::new(ret))
     }
 
     /// For a package, return all targets which are registered as dependencies
@@ -776,7 +809,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         // actually depend on anything, we've reached the end of the dependency
         // chain as we've got all the info we're gonna get.
         let key = (unit.pkg.package_id().clone(), unit.kind);
-        if self.build_state.outputs.lock().unwrap().contains_key(&key) {
+        if self.build_script_overridden.contains(&key) {
             return Ok(Vec::new())
         }
 

src/cargo/ops/cargo_rustc/custom_build.rs

@@ -77,7 +77,9 @@ pub fn prepare<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>)
                          -> CargoResult<(Work, Work, Freshness)> {
     let _p = profile::start(format!("build script prepare: {}/{}",
                                     unit.pkg, unit.target.name()));
-    let overridden = cx.build_state.has_override(unit);
+
+    let key = (unit.pkg.package_id().clone(), unit.kind);
+    let overridden = cx.build_script_overridden.contains(&key);
     let (work_dirty, work_fresh) = if overridden {
         (Work::noop(), Work::noop())
     } else {
@@ -314,18 +316,6 @@ impl BuildState {
     fn insert(&self, id: PackageId, kind: Kind, output: BuildOutput) {
         self.outputs.lock().unwrap().insert((id, kind), output);
     }
-
-    fn has_override(&self, unit: &Unit) -> bool {
-        let key = unit.pkg.manifest().links().map(|l| (l.to_string(), unit.kind));
-        match key.and_then(|k| self.overrides.get(&k)) {
-            Some(output) => {
-                self.insert(unit.pkg.package_id().clone(), unit.kind,
-                            output.clone());
-                true
-            }
-            None => false,
-        }
-    }
 }
 
 impl BuildOutput {
@@ -483,7 +473,7 @@ pub fn build_map<'b, 'cfg>(cx: &mut Context<'b, 'cfg>,
     // Recursive function to build up the map we're constructing. This function
     // memoizes all of its return values as it goes along.
     fn build<'a, 'b, 'cfg>(out: &'a mut HashMap<Unit<'b>, BuildScripts>,
-                           cx: &Context<'b, 'cfg>,
+                           cx: &mut Context<'b, 'cfg>,
                            unit: &Unit<'b>)
                            -> CargoResult<&'a BuildScripts> {
         // Do a quick pre-flight check to see if we've already calculated the
@@ -492,6 +482,20 @@ pub fn build_map<'b, 'cfg>(cx: &mut Context<'b, 'cfg>,
             return Ok(&out[unit])
         }
 
+        {
+            let key = unit.pkg.manifest().links().map(|l| (l.to_string(), unit.kind));
+            let build_state = &cx.build_state;
+            if let Some(output) = key.and_then(|k| build_state.overrides.get(&k)) {
+                let key = (unit.pkg.package_id().clone(), unit.kind);
+                cx.build_script_overridden.insert(key.clone());
+                build_state
+                    .outputs
+                    .lock()
+                    .unwrap()
+                    .insert(key, output.clone());
+            }
+        }
+
         let mut ret = BuildScripts::default();
 
         if !unit.target.is_custom_build() && unit.pkg.has_custom_build() {

src/cargo/ops/cargo_rustc/fingerprint.rs

@@ -538,7 +538,7 @@ fn write_fingerprint(loc: &Path, fingerprint: &Fingerprint) -> CargoResult<()> {
 }
 
 /// Prepare for work when a package starts to build
-pub fn prepare_init(cx: &mut Context, unit: &Unit) -> CargoResult<()> {
+pub fn prepare_init<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult<()> {
     let new1 = cx.fingerprint_dir(unit);
 
     if fs::metadata(&new1).is_err() {
@@ -548,7 +548,7 @@ pub fn prepare_init(cx: &mut Context, unit: &Unit) -> CargoResult<()> {
     Ok(())
 }
 
-pub fn dep_info_loc(cx: &mut Context, unit: &Unit) -> PathBuf {
+pub fn dep_info_loc<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> PathBuf {
     cx.fingerprint_dir(unit).join(&format!("dep-{}", filename(cx, unit)))
 }
 
@@ -670,7 +670,7 @@ fn mtime_if_fresh<I>(output: &Path, paths: I) -> Option<FileTime>
     }
 }
 
-fn filename(cx: &mut Context, unit: &Unit) -> String {
+fn filename<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> String {
     // file_stem includes metadata hash. Thus we have a different
     // fingerprint for every metadata hash version. This works because
     // even if the package is fresh, we'll still link the fresh target

src/cargo/ops/cargo_rustc/mod.rs

@@ -684,10 +684,10 @@ fn root_path(cx: &Context, unit: &Unit) -> PathBuf {
     }
 }
 
-fn build_base_args(cx: &mut Context,
-                   cmd: &mut ProcessBuilder,
-                   unit: &Unit,
-                   crate_types: &[&str]) {
+fn build_base_args<'a, 'cfg>(cx: &mut Context<'a, 'cfg>,
+                             cmd: &mut ProcessBuilder,
+                             unit: &Unit<'a>,
+                             crate_types: &[&str]) {
     let Profile {
         ref opt_level, lto, codegen_units, ref rustc_args, debuginfo,
         debug_assertions, overflow_checks, rpath, test, doc: _doc,

tests/workspaces.rs

@@ -1465,3 +1465,96 @@ Caused by:
 "));
 }
 
+/// This is a freshness test for feature use with workspaces
+///
+/// feat_lib is used by caller1 and caller2, but with different features enabled.
+/// This test ensures that alternating building caller1, caller2 doesn't force
+/// recompile of feat_lib.
+///
+/// Ideally once we solve https://github.com/rust-lang/cargo/issues/3620, then
+/// a single cargo build at the top level will be enough.
+#[test]
+fn dep_used_with_separate_features() {
+    let p = project("foo")
+        .file("Cargo.toml", r#"
+            [workspace]
+            members = ["feat_lib", "caller1", "caller2"]
+        "#)
+        .file("feat_lib/Cargo.toml", r#"
+            [project]
+            name = "feat_lib"
+            version = "0.1.0"
+            authors = []
+
+            [features]
+            myfeature = []
+        "#)
+        .file("feat_lib/src/lib.rs", "")
+        .file("caller1/Cargo.toml", r#"
+            [project]
+            name = "caller1"
+            version = "0.1.0"
+            authors = []
+
+            [dependencies]
+            feat_lib = { path = "../feat_lib" }
+        "#)
+        .file("caller1/src/main.rs", "fn main() {}")
+        .file("caller1/src/lib.rs", "")
+        .file("caller2/Cargo.toml", r#"
+            [project]
+            name = "caller2"
+            version = "0.1.0"
+            authors = []
+
+            [dependencies]
+            feat_lib = { path = "../feat_lib", features = ["myfeature"] }
+            caller1 = { path = "../caller1" }
+        "#)
+        .file("caller2/src/main.rs", "fn main() {}")
+        .file("caller2/src/lib.rs", "");
+    p.build();
+
+    // Build the entire workspace
+    assert_that(p.cargo("build").arg("--all"),
+                execs().with_status(0)
+                       .with_stderr("\
+[..]Compiling feat_lib v0.1.0 ([..])
+[..]Compiling caller1 v0.1.0 ([..])
+[..]Compiling caller2 v0.1.0 ([..])
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+"));
+    assert_that(&p.bin("caller1"), existing_file());
+    assert_that(&p.bin("caller2"), existing_file());
+
+
+    // Build caller1. should build the dep library. Because the features
+    // are different than the full workspace, it rebuilds.
+    // Ideally once we solve https://github.com/rust-lang/cargo/issues/3620, then
+    // a single cargo build at the top level will be enough.
+    assert_that(p.cargo("build").cwd(p.root().join("caller1")),
+                execs().with_status(0)
+                       .with_stderr("\
+[..]Compiling feat_lib v0.1.0 ([..])
+[..]Compiling caller1 v0.1.0 ([..])
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+"));
+
+    // Alternate building caller2/caller1 a few times, just to make sure
+    // features are being built separately.  Should not rebuild anything
+    assert_that(p.cargo("build").cwd(p.root().join("caller2")),
+                execs().with_status(0)
+                       .with_stderr("\
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+"));
+    assert_that(p.cargo("build").cwd(p.root().join("caller1")),
+                execs().with_status(0)
+                       .with_stderr("\
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+"));
+    assert_that(p.cargo("build").cwd(p.root().join("caller2")),
+                execs().with_status(0)
+                       .with_stderr("\
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
+"));
+}