From dd0aea350cb529eafbccc7ee65e98a72cfa09839 Mon Sep 17 00:00:00 2001
From: Weihang Lo <me@weihanglo.tw>
Date: Tue, 31 Oct 2023 00:42:37 -0400
Subject: [PATCH] feat(trim-paths): set env `CARGO_TRIM_PATHS` for build
 scripts

---
 src/cargo/core/compiler/custom_build.rs |  4 ++
 src/cargo/core/profiles.rs              |  1 +
 tests/testsuite/profile_trim_paths.rs   | 66 +++++++++++++++++++++++++
 3 files changed, 71 insertions(+)

diff --git a/src/cargo/core/compiler/custom_build.rs b/src/cargo/core/compiler/custom_build.rs
index 022ad87613a..c921986a838 100644
--- a/src/cargo/core/compiler/custom_build.rs
+++ b/src/cargo/core/compiler/custom_build.rs
@@ -307,6 +307,10 @@ fn build_work(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Job> {
         cmd.env("CARGO_MANIFEST_LINKS", links);
     }
 
+    if let Some(trim_paths) = unit.profile.trim_paths.as_ref() {
+        cmd.env("CARGO_TRIM_PATHS", trim_paths.to_string());
+    }
+
     // Be sure to pass along all enabled features for this package, this is the
     // last piece of statically known information that we have.
     for feat in &unit.features {
diff --git a/src/cargo/core/profiles.rs b/src/cargo/core/profiles.rs
index 06a5f3b5784..95354a3f6ad 100644
--- a/src/cargo/core/profiles.rs
+++ b/src/cargo/core/profiles.rs
@@ -327,6 +327,7 @@ impl Profiles {
         result.root = for_unit_profile.root;
         result.debuginfo = for_unit_profile.debuginfo;
         result.opt_level = for_unit_profile.opt_level;
+        result.trim_paths = for_unit_profile.trim_paths.clone();
         result
     }
 
diff --git a/tests/testsuite/profile_trim_paths.rs b/tests/testsuite/profile_trim_paths.rs
index b0b8d9577a4..f264253c936 100644
--- a/tests/testsuite/profile_trim_paths.rs
+++ b/tests/testsuite/profile_trim_paths.rs
@@ -511,3 +511,69 @@ fn object_works() {
     assert!(memchr::memmem::find(&stdout, registry_src_bytes).is_none());
     assert!(memchr::memmem::find(&stdout, pkg_root).is_none());
 }
+
+// TODO: might want to move to test/testsuite/build_script.rs once stabilized.
+#[cargo_test(nightly, reason = "-Zremap-path-scope is unstable")]
+fn custom_build_env_var_trim_paths() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+           "#,
+        )
+        .file("src/lib.rs", "")
+        .file("build.rs", "")
+        .build();
+
+    let test_cases = [
+        ("[]", "none"),
+        ("\"all\"", "all"),
+        ("\"diagnostics\"", "diagnostics"),
+        ("\"macro\"", "macro"),
+        ("\"none\"", "none"),
+        ("\"object\"", "object"),
+        ("false", "none"),
+        ("true", "all"),
+        (
+            r#"["diagnostics", "macro", "object"]"#,
+            "diagnostics,macro,object",
+        ),
+    ];
+
+    for (opts, expected) in test_cases {
+        p.change_file(
+            "Cargo.toml",
+            &format!(
+                r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+
+                [profile.dev]
+                trim-paths = {opts}
+                "#
+            ),
+        );
+
+        p.change_file(
+            "build.rs",
+            &format!(
+                r#"
+                fn main() {{
+                    assert_eq!(
+                        std::env::var("CARGO_TRIM_PATHS").unwrap().as_str(),
+                        "{expected}",
+                    );
+                }}
+                "#
+            ),
+        );
+
+        p.cargo("build -Ztrim-paths")
+            .masquerade_as_nightly_cargo(&["-Ztrim-paths"])
+            .run();
+    }
+}