Read default cfgs from rustc

crates/ra_project_model/src/cargo_workspace.rs

@@ -39,6 +39,7 @@ struct PackageData {
     is_member: bool,
     dependencies: Vec<PackageDependency>,
     edition: Edition,
+    features: Vec<String>,
 }
 
 #[derive(Debug, Clone)]
@@ -91,6 +92,9 @@ impl Package {
     pub fn edition(self, ws: &CargoWorkspace) -> Edition {
         ws.packages[self].edition
     }
+    pub fn features(self, ws: &CargoWorkspace) -> &[String] {
+        &ws.packages[self].features
+    }
     pub fn targets<'a>(self, ws: &'a CargoWorkspace) -> impl Iterator<Item = Target> + 'a {
         ws.packages[self].targets.iter().cloned()
     }
@@ -144,6 +148,7 @@ impl CargoWorkspace {
                 is_member,
                 edition: Edition::from_string(&meta_pkg.edition),
                 dependencies: Vec::new(),
+                features: Vec::new(),
             });
             let pkg_data = &mut packages[pkg];
             pkg_by_id.insert(meta_pkg.id.clone(), pkg);
@@ -164,6 +169,7 @@ impl CargoWorkspace {
                 let dep = PackageDependency { name: dep_node.name, pkg: pkg_by_id[&dep_node.pkg] };
                 packages[source].dependencies.push(dep);
             }
+            packages[source].features.extend(node.features);
         }
 
         Ok(CargoWorkspace { packages, targets, workspace_root: meta.workspace_root })

crates/ra_project_model/src/json_project.rs

@@ -19,6 +19,8 @@ pub struct Crate {
     pub(crate) root_module: PathBuf,
     pub(crate) edition: Edition,
     pub(crate) deps: Vec<Dep>,
+    #[serde(default)]
+    pub(crate) features: Vec<String>,
 }
 
 #[derive(Clone, Copy, Debug, Deserialize)]

crates/ra_project_model/src/lib.rs

@@ -9,6 +9,7 @@ use std::{
     fs::File,
     io::BufReader,
     path::{Path, PathBuf},
+    process::Command,
 };
 
 use ra_cfg::CfgOptions;
@@ -118,6 +119,7 @@ impl ProjectWorkspace {
 
     pub fn to_crate_graph(
         &self,
+        default_cfg_options: &CfgOptions,
         load: &mut dyn FnMut(&Path) -> Option<FileId>,
     ) -> (CrateGraph, FxHashMap<CrateId, String>) {
         let mut crate_graph = CrateGraph::default();
@@ -134,7 +136,9 @@ impl ProjectWorkspace {
                         };
                         // FIXME: cfg options
                         // Default to enable test for workspace crates.
-                        let cfg_options = CfgOptions::default().atom("test".into());
+                        let cfg_options = default_cfg_options
+                            .clone()
+                            .features(krate.features.iter().map(Into::into));
                         crates.insert(
                             crate_id,
                             crate_graph.add_crate_root(file_id, edition, cfg_options),
@@ -164,9 +168,8 @@ impl ProjectWorkspace {
                 let mut sysroot_crates = FxHashMap::default();
                 for krate in sysroot.crates() {
                     if let Some(file_id) = load(krate.root(&sysroot)) {
-                        // FIXME: cfg options
                         // Crates from sysroot have `cfg(test)` disabled
-                        let cfg_options = CfgOptions::default();
+                        let cfg_options = default_cfg_options.clone().remove_atom(&"test".into());
                         let crate_id =
                             crate_graph.add_crate_root(file_id, Edition::Edition2018, cfg_options);
                         sysroot_crates.insert(krate, crate_id);
@@ -197,9 +200,9 @@ impl ProjectWorkspace {
                         let root = tgt.root(&cargo);
                         if let Some(file_id) = load(root) {
                             let edition = pkg.edition(&cargo);
-                            // FIXME: cfg options
-                            // Default to enable test for workspace crates.
-                            let cfg_options = CfgOptions::default().atom("test".into());
+                            let cfg_options = default_cfg_options
+                                .clone()
+                                .features(pkg.features(&cargo).iter().map(Into::into));
                             let crate_id =
                                 crate_graph.add_crate_root(file_id, edition, cfg_options);
                             names.insert(crate_id, pkg.name(&cargo).to_string());
@@ -301,3 +304,32 @@ fn find_cargo_toml(path: &Path) -> Result<PathBuf> {
     }
     Err(format!("can't find Cargo.toml at {}", path.display()))?
 }
+
+pub fn get_rustc_cfg_options() -> CfgOptions {
+    let mut cfg_options = CfgOptions::default();
+
+    match (|| -> Result<_> {
+        // `cfg(test)` ans `cfg(debug_assertion)` is handled outside, so we suppress them here.
+        let output = Command::new("rustc").args(&["--print", "cfg", "-O"]).output()?;
+        if !output.status.success() {
+            Err("failed to get rustc cfgs")?;
+        }
+        Ok(String::from_utf8(output.stdout)?)
+    })() {
+        Ok(rustc_cfgs) => {
+            for line in rustc_cfgs.lines() {
+                match line.find('=') {
+                    None => cfg_options = cfg_options.atom(line.into()),
+                    Some(pos) => {
+                        let key = &line[..pos];
+                        let value = line[pos + 1..].trim_matches('"');
+                        cfg_options = cfg_options.key_value(key.into(), value.into());
+                    }
+                }
+            }
+        }
+        Err(e) => log::error!("failed to get rustc cfgs: {}", e),
+    }
+
+    cfg_options
+}