Add cargo.extraEnv setting

Author: dpaoliello

crates/rust-analyzer/src/config.rs

@@ -83,6 +83,9 @@ config_data! {
         /// Use `RUSTC_WRAPPER=rust-analyzer` when running build scripts to
         /// avoid checking unnecessary things.
         cargo_buildScripts_useRustcWrapper: bool = "true",
+        /// Extra environment variables that will be set when running cargo, rustc
+        /// or other commands within the workspace. Useful for setting RUSTFLAGS.
+        cargo_extraEnv: FxHashMap<String, String> = "{}",
         /// List of features to activate.
         ///
         /// Set this to `"all"` to pass `--all-features` to cargo.
@@ -896,6 +899,10 @@ impl Config {
         }
     }
 
+    pub fn extra_env(&self) -> &FxHashMap<String, String> {
+        &self.data.cargo_extraEnv
+    }
+
     pub fn lru_capacity(&self) -> Option<usize> {
         self.data.lru_capacity
     }

crates/rust-analyzer/src/global_state.rs

@@ -3,7 +3,7 @@
 //!
 //! Each tick provides an immutable snapshot of the state as `WorldSnapshot`.
 
-use std::{sync::Arc, time::Instant};
+use std::{ffi::OsString, sync::Arc, time::Instant};
 
 use crossbeam_channel::{unbounded, Receiver, Sender};
 use flycheck::FlycheckHandle;
@@ -62,6 +62,7 @@ pub(crate) struct GlobalState {
     pub(crate) last_reported_status: Option<lsp_ext::ServerStatusParams>,
     pub(crate) source_root_config: SourceRootConfig,
     pub(crate) proc_macro_clients: Vec<Result<ProcMacroServer, String>>,
+    pub(crate) overwritten_env_vars: Vec<(String, Option<OsString>)>,
 
     pub(crate) flycheck: Vec<FlycheckHandle>,
     pub(crate) flycheck_sender: Sender<flycheck::Message>,
@@ -152,6 +153,7 @@ impl GlobalState {
             last_reported_status: None,
             source_root_config: SourceRootConfig::default(),
             proc_macro_clients: vec![],
+            overwritten_env_vars: Vec::new(),
 
             flycheck: Vec::new(),
             flycheck_sender,

crates/rust-analyzer/src/reload.rs

@@ -12,7 +12,7 @@
 //! correct. Instead, we try to provide a best-effort service. Even if the
 //! project is currently loading and we don't have a full project model, we
 //! still want to respond to various  requests.
-use std::{mem, sync::Arc};
+use std::{env, mem, sync::Arc};
 
 use flycheck::{FlycheckConfig, FlycheckHandle};
 use hir::db::DefDatabase;
@@ -59,11 +59,25 @@ impl GlobalState {
     pub(crate) fn update_configuration(&mut self, config: Config) {
         let _p = profile::span("GlobalState::update_configuration");
         let old_config = mem::replace(&mut self.config, Arc::new(config));
+        let env_changed = self.config.extra_env() != old_config.extra_env();
+        if env_changed {
+            for (old_key, old_value) in self.overwritten_env_vars.drain(..) {
+                if let Some(old_value) = old_value {
+                    env::set_var(old_key, old_value);
+                } else {
+                    env::remove_var(old_key);
+                }
+            }
+            for (new_key, new_value) in self.config.extra_env() {
+                self.overwritten_env_vars.push((new_key.clone(), std::env::var_os(new_key)));
+                std::env::set_var(new_key, new_value);
+            }
+        }
         if self.config.lru_capacity() != old_config.lru_capacity() {
             self.analysis_host.update_lru_capacity(self.config.lru_capacity());
         }
-        if self.config.linked_projects() != old_config.linked_projects() {
-            self.fetch_workspaces_queue.request_op("linked projects changed".to_string())
+        if env_changed || self.config.linked_projects() != old_config.linked_projects() {
+            self.fetch_workspaces_queue.request_op("env or linked projects changed".to_string())
         } else if self.config.flycheck() != old_config.flycheck() {
             self.reload_flycheck();
         }

docs/user/generated_config.adoc

@@ -46,6 +46,12 @@ cargo check --quiet --workspace --message-format=json --all-targets
 Use `RUSTC_WRAPPER=rust-analyzer` when running build scripts to
 avoid checking unnecessary things.
 --
+[[rust-analyzer.cargo.extraEnv]]rust-analyzer.cargo.extraEnv (default: `{}`)::
++
+--
+Extra environment variables that will be set when running cargo, rustc
+or other commands within the workspace. Useful for setting RUSTFLAGS.
+--
 [[rust-analyzer.cargo.features]]rust-analyzer.cargo.features (default: `[]`)::
 +
 --

editors/code/package.json

@@ -437,6 +437,11 @@
                     "default": true,
                     "type": "boolean"
                 },
+                "rust-analyzer.cargo.extraEnv": {
+                    "markdownDescription": "Extra environment variables that will be set when running cargo, rustc\nor other commands within the workspace. Useful for setting RUSTFLAGS.",
+                    "default": {},
+                    "type": "object"
+                },
                 "rust-analyzer.cargo.features": {
                     "markdownDescription": "List of features to activate.\n\nSet this to `\"all\"` to pass `--all-features` to cargo.",
                     "default": [],