fix(env): cargo:rerun-if-env-changed doesn't work with env configuration

src/cargo/core/compiler/build_context/target_info.rs

@@ -21,6 +21,8 @@ use cargo_util::{paths, ProcessBuilder};
 use serde::{Deserialize, Serialize};
 use std::cell::RefCell;
 use std::collections::hash_map::{Entry, HashMap};
+use std::collections::BTreeMap;
+use std::ffi::OsString;
 use std::path::{Path, PathBuf};
 use std::str::{self, FromStr};
 
@@ -588,6 +590,10 @@ impl TargetInfo {
             .iter()
             .any(|sup| sup.as_str() == split.as_str())
     }
+
+    pub fn get_target_envs(&self) -> &BTreeMap<String, Option<OsString>> {
+        return self.crate_type_process.get_envs();
+    }
 }
 
 /// Takes rustc output (using specialized command line args), and calculates the file prefix and

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

@@ -357,7 +357,9 @@ mod dirty_reason;
 
 use std::collections::hash_map::{Entry, HashMap};
 
+use std::collections::BTreeMap;
 use std::env;
+use std::ffi::OsString;
 use std::hash::{self, Hash, Hasher};
 use std::io;
 use std::path::{Path, PathBuf};
@@ -768,14 +770,35 @@ pub enum StaleItem {
 impl LocalFingerprint {
     /// Read the environment variable of the given env `key`, and creates a new
     /// [`LocalFingerprint::RerunIfEnvChanged`] for it.
-    ///
-    // TODO: This is allowed at this moment. Should figure out if it makes
-    // sense if permitting to read env from the config system.
     #[allow(clippy::disallowed_methods)]
-    fn from_env<K: AsRef<str>>(key: K) -> LocalFingerprint {
-        let key = key.as_ref();
+    fn from_env<K: AsRef<str>>(
+        key: K,
+        envs: &BTreeMap<String, Option<OsString>>,
+    ) -> LocalFingerprint {
+        fn get_envs_case_insensitive(
+            key: &str,
+            envs: &BTreeMap<String, Option<OsString>>,
+        ) -> Option<OsString> {
+            let upper_case_key: String = key.to_uppercase();
+            for (k, v) in envs {
+                if k.to_uppercase().eq(&upper_case_key) {
+                    return v.to_owned();
+                }
+            }
+            None
+        }
+
+        let key: &str = key.as_ref();
         let var = key.to_owned();
-        let val = env::var(key).ok();
+
+        let val: Option<String> = if cfg!(windows) {
+            get_envs_case_insensitive(key, envs)
+        } else {
+            envs.get(key).and_then(|v| v.to_owned())
+        }
+        .or(env::var_os(key))
+        .and_then(|os_str| os_str.into_string().ok());
+
         LocalFingerprint::RerunIfEnvChanged { var, val }
     }
 
@@ -1608,6 +1631,12 @@ fn build_script_local_fingerprints(
     bool,
 ) {
     assert!(unit.mode.is_run_custom_build());
+    let envs = build_runner
+        .bcx
+        .target_data
+        .info(unit.kind)
+        .get_target_envs()
+        .clone();
     // First up, if this build script is entirely overridden, then we just
     // return the hash of what we overrode it with. This is the easy case!
     if let Some(fingerprint) = build_script_override_fingerprint(build_runner, unit) {
@@ -1660,7 +1689,12 @@ fn build_script_local_fingerprints(
             // Ok so now we're in "new mode" where we can have files listed as
             // dependencies as well as env vars listed as dependencies. Process
             // them all here.
-            Ok(Some(local_fingerprints_deps(deps, &target_dir, &pkg_root)))
+            Ok(Some(local_fingerprints_deps(
+                deps,
+                &target_dir,
+                &pkg_root,
+                &envs,
+            )))
         };
 
     // Note that `false` == "not overridden"
@@ -1695,6 +1729,7 @@ fn local_fingerprints_deps(
     deps: &BuildDeps,
     target_root: &Path,
     pkg_root: &Path,
+    envs: &BTreeMap<String, Option<OsString>>,
 ) -> Vec<LocalFingerprint> {
     debug!("new local fingerprints deps {:?}", pkg_root);
     let mut local = Vec::new();
@@ -1719,7 +1754,7 @@ fn local_fingerprints_deps(
     local.extend(
         deps.rerun_if_env_changed
             .iter()
-            .map(LocalFingerprint::from_env),
+            .map(|v| LocalFingerprint::from_env(v, &envs)),
     );
 
     local

tests/testsuite/build_script_env.rs

@@ -20,13 +20,13 @@ fn rerun_if_env_changes_config() {
         .file(
             "build.rs",
             r#"
-                fn main() {
-                    println!("cargo:rerun-if-env-changed=FOO");
-                    if let Ok(foo) = std::env::var("FOO") {
-                        assert!(&foo != "bad");
-                    }
-                }
-            "#,
+fn main() {
+    println!("cargo:rerun-if-env-changed=FOO");
+    if let Ok(foo) = std::env::var("FOO") {
+        assert!(&foo != "bad");
+    }
+}
+"#,
         )
         .build();
 
@@ -47,47 +47,38 @@ fn rerun_if_env_changes_config() {
     );
 
     p.cargo("check")
+        .with_status(101)
         .with_stderr_data(str![[r#"
-[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
-
+[COMPILING] foo v0.1.0 ([ROOT]/foo)
+[ERROR] failed to run custom build command for `foo v0.1.0 ([ROOT]/foo)`
+...
 "#]])
         .run();
-
-    p.cargo("clean").run();
-    p.cargo("check")
-        .with_status(101)
-        .with_stderr_data(
-            "\
-            [COMPILING] foo v0.1.0 ([ROOT]/foo)
-[ERROR] failed to run custom build command for `foo v0.1.0 ([..])`
-...",
-        )
-        .run();
 }
 
 #[cfg(windows)]
 #[cargo_test]
-fn rerun_if_env_changes_config_windows() {
+fn rerun_if_env_changes_config_in_windows() {
     let p = project()
         .file("Cargo.toml", &basic_manifest("foo", "0.1.0"))
         .file("src/main.rs", "fn main() {}")
         .file(
             ".cargo/config.toml",
             r#"
                 [env]
-                FOO = "good"
+                Foo = "good"
             "#,
         )
         .file(
             "build.rs",
             r#"
-                fn main() {
-                    println!("cargo:rerun-if-env-changed=Foo");
-                    if let Ok(foo) = std::env::var("Foo") {
-                        assert!(&foo != "bad");
-                    }
-                }
-            "#,
+fn main() {
+    println!("cargo:rerun-if-env-changed=foo");
+    if let Ok(foo) = std::env::var("FOo") {
+        assert!(&foo != "bad");
+    }
+}
+"#,
         )
         .build();
 
@@ -103,26 +94,17 @@ fn rerun_if_env_changes_config_windows() {
         ".cargo/config.toml",
         r#"
             [env]
-            FOO = "bad"
+            FoO = "bad"
         "#,
     );
 
-    p.cargo("check")
-        .with_stderr_data(str![[r#"
-[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
-
-"#]])
-        .run();
-
-    p.cargo("clean").run();
     p.cargo("check")
         .with_status(101)
-        .with_stderr_data(
-            "\
+        .with_stderr_data(str![[r#"
 [COMPILING] foo v0.1.0 ([ROOT]/foo)
-[ERROR] failed to run custom build command for `foo v0.1.0 ([..])`
-...",
-        )
+[ERROR] failed to run custom build command for `foo v0.1.0 ([ROOT]/foo)`
+...
+"#]])
         .run();
 }
 
@@ -158,6 +140,7 @@ fn rerun_if_env_changes_cargo_set_env_variable() {
 
     p.cargo("check")
         .with_stderr_data(str![[r#"
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
 [FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
 
 "#]])