Add detect while using environment variable

Author: LuuuXXX

src/cargo/core/compiler/mod.rs

@@ -190,27 +190,29 @@ fn compile<'gctx>(
     } else {
         let force = exec.force_rebuild(unit) || force_rebuild;
         let mut job = fingerprint::prepare_target(build_runner, unit, force)?;
-        job.before(if job.freshness().is_dirty() {
-            let work = if unit.mode.is_doc() || unit.mode.is_doc_scrape() {
-                rustdoc(build_runner, unit)?
+        job.before(
+            if job.freshness().is_dirty() || env_config_modified(bcx.gctx)? {
+                let work = if unit.mode.is_doc() || unit.mode.is_doc_scrape() {
+                    rustdoc(build_runner, unit)?
+                } else {
+                    rustc(build_runner, unit, exec)?
+                };
+                work.then(link_targets(build_runner, unit, false)?)
             } else {
-                rustc(build_runner, unit, exec)?
-            };
-            work.then(link_targets(build_runner, unit, false)?)
-        } else {
-            // We always replay the output cache,
-            // since it might contain future-incompat-report messages
-            let work = replay_output_cache(
-                unit.pkg.package_id(),
-                PathBuf::from(unit.pkg.manifest_path()),
-                &unit.target,
-                build_runner.files().message_cache_path(unit),
-                build_runner.bcx.build_config.message_format,
-                unit.show_warnings(bcx.gctx),
-            );
-            // Need to link targets on both the dirty and fresh.
-            work.then(link_targets(build_runner, unit, true)?)
-        });
+                // We always replay the output cache,
+                // since it might contain future-incompat-report messages
+                let work = replay_output_cache(
+                    unit.pkg.package_id(),
+                    PathBuf::from(unit.pkg.manifest_path()),
+                    &unit.target,
+                    build_runner.files().message_cache_path(unit),
+                    build_runner.bcx.build_config.message_format,
+                    unit.show_warnings(bcx.gctx),
+                );
+                // Need to link targets on both the dirty and fresh.
+                work.then(link_targets(build_runner, unit, true)?)
+            },
+        );
 
         job
     };
@@ -1926,6 +1928,21 @@ fn should_include_scrape_units(bcx: &BuildContext<'_, '_>, unit: &Unit) -> bool
     unit.mode.is_doc() && bcx.scrape_units.len() > 0 && bcx.ws.unit_needs_doc_scrape(unit)
 }
 
+/// Detects if environment variables from config `[env]` is newly modified.
+fn env_config_modified(gctx: &crate::GlobalContext) -> CargoResult<bool> {
+    for (key, value) in gctx.env_config()?.iter() {
+        if !gctx.env().any(|(k, _)| k == key) {
+            continue;
+        }
+
+        if !value.is_force() && gctx.env().find(|(k, _)| k == key).is_some() {
+            return Ok(true);
+        }
+    }
+
+    Ok(false)
+}
+
 /// Gets the file path of function call information output from `rustdoc`.
 fn scrape_output_path(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> CargoResult<PathBuf> {
     assert!(unit.mode.is_doc() || unit.mode.is_doc_scrape());