refactor: env_config supports resolve case insensitive env.

src/cargo/core/compiler/fingerprint/dep_info.rs

@@ -4,7 +4,6 @@
 //! [the documentation]: crate::core::compiler::fingerprint#dep-info-files
 
 use std::collections::HashMap;
-use std::ffi::OsString;
 use std::fmt;
 use std::io;
 use std::io::Read;
@@ -19,6 +18,7 @@ use cargo_util::paths;
 use cargo_util::ProcessBuilder;
 use cargo_util::Sha256;
 
+use crate::util::context::EnvConfigResolved;
 use crate::CargoResult;
 use crate::CARGO_ENV;
 
@@ -294,7 +294,7 @@ pub fn translate_dep_info(
     target_root: &Path,
     rustc_cmd: &ProcessBuilder,
     allow_package: bool,
-    env_config: &Arc<HashMap<String, OsString>>,
+    env_config: &Arc<EnvConfigResolved>,
 ) -> CargoResult<()> {
     let depinfo = parse_rustc_dep_info(rustc_dep_info)?;
 
@@ -334,7 +334,9 @@ pub fn translate_dep_info(
     //
     // For cargo#13280, We trace env vars that are defined in the `[env]` config table.
     on_disk_info.env.retain(|(key, _)| {
-        env_config.contains_key(key) || !rustc_cmd.get_envs().contains_key(key) || key == CARGO_ENV
+        env_config.env.contains_key(key)
+            || !rustc_cmd.get_envs().contains_key(key)
+            || key == CARGO_ENV
     });
 
     let serialize_path = |file| {

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

@@ -362,10 +362,8 @@
 mod dep_info;
 mod dirty_reason;
 
-use std::cell::OnceCell;
 use std::collections::hash_map::{Entry, HashMap};
 use std::env;
-use std::ffi::OsString;
 use std::fs;
 use std::fs::File;
 use std::hash::{self, Hash, Hasher};
@@ -382,10 +380,12 @@ use serde::de;
 use serde::ser;
 use serde::{Deserialize, Serialize};
 use tracing::{debug, info};
+use unicase::Ascii as UncasedAscii;
 
 use crate::core::compiler::unit_graph::UnitDep;
 use crate::core::Package;
 use crate::util;
+use crate::util::context::EnvConfigResolved;
 use crate::util::errors::CargoResult;
 use crate::util::interning::InternedString;
 use crate::util::{internal, path_args, StableHasher};
@@ -799,25 +799,19 @@ impl LocalFingerprint {
     /// Read the environment variable of the given env `key`, and creates a new
     /// [`LocalFingerprint::RerunIfEnvChanged`] for it.
     #[allow(clippy::disallowed_methods)]
-    fn from_env<K: AsRef<str>>(
-        key: K,
-        env_config: &Arc<HashMap<String, OsString>>,
-        env_config_insensitive: &Arc<OnceCell<HashMap<String, OsString>>>,
-    ) -> LocalFingerprint {
+    fn from_env<K: AsRef<str>>(key: K, env_config: &Arc<EnvConfigResolved>) -> LocalFingerprint {
         let key = key.as_ref();
         let var = key.to_owned();
-        let val = if let Some(val) = match env_config.get(key) {
+        let val = if let Some(val) = match env_config.env.get(key) {
             Some(value) => value.to_str().map(|s| s.to_owned()),
             None => {
                 if cfg!(windows) {
-                    env_config_insensitive
-                        .get_or_init(|| {
-                            env_config
-                                .iter()
-                                .map(|(k, v)| (k.to_uppercase().clone(), v.clone()))
-                                .collect()
+                    env_config
+                        .case_insensitive_env
+                        .as_ref()
+                        .and_then(|case_insensitive_env| {
+                            case_insensitive_env.get(&UncasedAscii::new(key.to_owned()))
                         })
-                        .get(&key.to_uppercase())
                         .and_then(|s| s.to_str().map(|s| s.to_owned()))
                 } else {
                     None
@@ -872,7 +866,7 @@ impl LocalFingerprint {
                             )
                         })?)
                     } else {
-                        if let Some(value) = gctx.env_config()?.get(key) {
+                        if let Some(value) = gctx.env_config()?.env.get(key) {
                             value.to_str()
                         } else {
                             gctx.get_env(key).ok()
@@ -1795,7 +1789,7 @@ fn local_fingerprints_deps(
     deps: &BuildDeps,
     target_root: &Path,
     pkg_root: &Path,
-    env_config: &Arc<HashMap<String, OsString>>,
+    env_config: &Arc<EnvConfigResolved>,
 ) -> Vec<LocalFingerprint> {
     debug!("new local fingerprints deps {:?}", pkg_root);
     let mut local = Vec::new();
@@ -1816,11 +1810,10 @@ fn local_fingerprints_deps(
             .collect();
         local.push(LocalFingerprint::RerunIfChanged { output, paths });
     }
-    let env_config_insensitive = Arc::new(OnceCell::new());
     local.extend(
         deps.rerun_if_env_changed
             .iter()
-            .map(|s| LocalFingerprint::from_env(s, env_config, &env_config_insensitive)),
+            .map(|s| LocalFingerprint::from_env(s, env_config)),
     );
 
     local

src/cargo/core/compiler/mod.rs

@@ -1983,7 +1983,7 @@ pub(crate) fn apply_env_config(
     gctx: &crate::GlobalContext,
     cmd: &mut ProcessBuilder,
 ) -> CargoResult<()> {
-    for (key, value) in gctx.env_config()?.iter() {
+    for (key, value) in gctx.env_config()?.env.iter() {
         // never override a value that has already been set by cargo
         if cmd.get_envs().contains_key(key) {
             continue;

src/cargo/util/context/mod.rs

@@ -91,6 +91,7 @@ use serde::Deserialize;
 use serde_untagged::UntaggedEnumVisitor;
 use time::OffsetDateTime;
 use toml_edit::Item;
+use unicase::Ascii as UncasedAscii;
 use url::Url;
 
 mod de;
@@ -227,7 +228,7 @@ pub struct GlobalContext {
     target_cfgs: LazyCell<Vec<(String, TargetCfgConfig)>>,
     doc_extern_map: LazyCell<RustdocExternMap>,
     progress_config: ProgressConfig,
-    env_config: LazyCell<Arc<HashMap<String, OsString>>>,
+    env_config: LazyCell<Arc<EnvConfigResolved>>,
     /// This should be false if:
     /// - this is an artifact of the rustc distribution process for "stable" or for "beta"
     /// - this is an `#[test]` that does not opt in with `enable_nightly_features`
@@ -1835,7 +1836,7 @@ impl GlobalContext {
 
     /// Get the env vars from the config `[env]` table which
     /// are `force = true` or don't exist in the env snapshot [`GlobalContext::get_env`].
-    pub fn env_config(&self) -> CargoResult<&Arc<HashMap<String, OsString>>> {
+    pub fn env_config(&self) -> CargoResult<&Arc<EnvConfigResolved>> {
         let env_config = self.env_config.try_borrow_with(|| {
             CargoResult::Ok(Arc::new({
                 let env_config = self.get::<EnvConfig>("env")?;
@@ -1862,7 +1863,7 @@ impl GlobalContext {
                         );
                     }
                 }
-                env_config
+                let env_config: HashMap<String, OsString> = env_config
                     .into_iter()
                     .filter_map(|(k, v)| {
                         if v.is_force() || self.get_env_os(&k).is_none() {
@@ -1871,7 +1872,23 @@ impl GlobalContext {
                             None
                         }
                     })
-                    .collect()
+                    .collect();
+                EnvConfigResolved {
+                    case_insensitive_env: {
+                        if cfg!(windows) {
+                            Some(
+                                env_config
+                                    .clone()
+                                    .into_iter()
+                                    .map(|(k, v)| (UncasedAscii::new(k), v))
+                                    .collect(),
+                            )
+                        } else {
+                            None
+                        }
+                    },
+                    env: env_config,
+                }
             }))
         })?;
 
@@ -2867,7 +2884,13 @@ impl EnvConfigValue {
     }
 }
 
-pub type EnvConfig = HashMap<String, EnvConfigValue>;
+type EnvConfig = HashMap<String, EnvConfigValue>;
+
+#[derive(Debug)]
+pub struct EnvConfigResolved {
+    pub case_insensitive_env: Option<HashMap<UncasedAscii<String>, OsString>>,
+    pub env: HashMap<String, OsString>,
+}
 
 fn parse_document(toml: &str, _file: &Path, _gctx: &GlobalContext) -> CargoResult<toml::Table> {
     // At the moment, no compatibility checks are needed.