[bazel] Improve runfiles handling (#10098)

we can't use runfiles directory on Windows due to path lengths, so swap
to manifest strategy. Parsing the manifest is a bit complex and the
format is changing in Bazel upstream, so pull in the official Rust
library (via a small hack to make it importable...) and cleanup all the
associated logic to work cleanly in both bazel and cargo without extra
confusion

.bazelignore

@@ -1,3 +1,4 @@
 # Without this, Bazel will consider BUILD.bazel files in
 # .git/sl/origbackups (which can be populated by Sapling SCM).
 .git
+codex-rs/target

.bazelrc

@@ -1,5 +1,7 @@
 common --repo_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1
 common --repo_env=BAZEL_NO_APPLE_CPP_TOOLCHAIN=1
+# Dummy xcode config so we don't need to build xcode_locator in repo rule.
+common --xcode_version_config=//:disable_xcode
 
 common --disk_cache=~/.cache/bazel-disk-cache
 common --repo_contents_cache=~/.cache/bazel-repo-contents-cache
@@ -9,6 +11,9 @@ startup --experimental_remote_repo_contents_cache
 
 common --experimental_platform_in_output_dir
 
+# Runfiles strategy rationale: codex-rs/utils/cargo-bin/README.md
+common --noenable_runfiles
+
 common --enable_platform_specific_config
 # TODO(zbarsky): We need to untangle these libc constraints to get linux remote builds working.
 common:linux --host_platform=//:local
@@ -44,4 +49,3 @@ common --jobs=30
 common:remote --extra_execution_platforms=//:rbe
 common:remote --remote_executor=grpcs://remote.buildbuddy.io
 common:remote --jobs=800
-

BUILD.bazel

@@ -1,3 +1,7 @@
+load("@apple_support//xcode:xcode_config.bzl", "xcode_config")
+
+xcode_config(name = "disable_xcode")
+
 # We mark the local platform as glibc-compatible so that rust can grab a toolchain for us.
 # TODO(zbarsky): Upstream a better libc constraint into rules_rust.
 # We only enable this on linux though for sanity, and because it breaks remote execution.

MODULE.bazel

@@ -27,6 +27,8 @@ register_toolchains(
     "@toolchains_llvm_bootstrapped//toolchain:all",
 )
 
+# Needed to disable xcode...
+bazel_dep(name = "apple_support", version = "2.1.0")
 bazel_dep(name = "rules_cc", version = "0.2.16")
 bazel_dep(name = "rules_platform", version = "0.1.0")
 bazel_dep(name = "rules_rust", version = "0.68.1")
@@ -90,6 +92,11 @@ crate.annotation(
 
 inject_repo(crate, "openssl")
 
+crate.annotation(
+    crate = "runfiles",
+    workspace_cargo_toml = "rust/runfiles/Cargo.toml",
+)
+
 # Fix readme inclusions
 crate.annotation(
     crate = "windows-link",

MODULE.bazel.lock

@@ -21,7 +21,8 @@
     "https://bcr.bazel.build/modules/apple_support/1.23.0/MODULE.bazel": "317d47e3f65b580e7fb4221c160797fda48e32f07d2dfff63d754ef2316dcd25",
     "https://bcr.bazel.build/modules/apple_support/1.24.1/MODULE.bazel": "f46e8ddad60aef170ee92b2f3d00ef66c147ceafea68b6877cb45bd91737f5f8",
     "https://bcr.bazel.build/modules/apple_support/1.24.2/MODULE.bazel": "0e62471818affb9f0b26f128831d5c40b074d32e6dda5a0d3852847215a41ca4",
-    "https://bcr.bazel.build/modules/apple_support/1.24.2/source.json": "2c22c9827093250406c5568da6c54e6fdf0ef06238def3d99c71b12feb057a8d",
+    "https://bcr.bazel.build/modules/apple_support/2.1.0/MODULE.bazel": "b15c125dabed01b6803c129cd384de4997759f02f8ec90dc5136bcf6dfc5086a",
+    "https://bcr.bazel.build/modules/apple_support/2.1.0/source.json": "78064cfefe18dee4faaf51893661e0d403784f3efe88671d727cdcdc67ed8fb3",
     "https://bcr.bazel.build/modules/aspect_bazel_lib/2.14.0/MODULE.bazel": "2b31ffcc9bdc8295b2167e07a757dbbc9ac8906e7028e5170a3708cecaac119f",
     "https://bcr.bazel.build/modules/aspect_bazel_lib/2.19.3/MODULE.bazel": "253d739ba126f62a5767d832765b12b59e9f8d2bc88cc1572f4a73e46eb298ca",
     "https://bcr.bazel.build/modules/aspect_bazel_lib/2.19.3/source.json": "ffab9254c65ba945f8369297ad97ca0dec213d3adc6e07877e23a48624a8b456",
@@ -790,6 +791,7 @@
       "gimli_0.31.1": "{\"dependencies\":[{\"name\":\"alloc\",\"optional\":true,\"package\":\"rustc-std-workspace-alloc\",\"req\":\"^1.0.0\"},{\"name\":\"compiler_builtins\",\"optional\":true,\"req\":\"^0.1.2\"},{\"name\":\"core\",\"optional\":true,\"package\":\"rustc-std-workspace-core\",\"req\":\"^1.0.0\"},{\"default_features\":false,\"name\":\"fallible-iterator\",\"optional\":true,\"req\":\"^0.3.0\"},{\"name\":\"indexmap\",\"optional\":true,\"req\":\"^2.0.0\"},{\"default_features\":false,\"name\":\"stable_deref_trait\",\"optional\":true,\"req\":\"^1.1.0\"},{\"kind\":\"dev\",\"name\":\"test-assembler\",\"req\":\"^0.1.3\"}],\"features\":{\"default\":[\"read-all\",\"write\"],\"endian-reader\":[\"read\",\"dep:stable_deref_trait\"],\"fallible-iterator\":[\"dep:fallible-iterator\"],\"read\":[\"read-core\"],\"read-all\":[\"read\",\"std\",\"fallible-iterator\",\"endian-reader\"],\"read-core\":[],\"rustc-dep-of-std\":[\"dep:core\",\"dep:alloc\",\"dep:compiler_builtins\"],\"std\":[\"fallible-iterator?/std\",\"stable_deref_trait?/std\"],\"write\":[\"dep:indexmap\"]}}",
       "git+https://github.com/JakkuSakura/tokio-tungstenite?rev=2ae536b0de793f3ddf31fc2f22d445bf1ef2023d#2ae536b0de793f3ddf31fc2f22d445bf1ef2023d_tokio-tungstenite": "{\"dependencies\":[{\"default_features\":false,\"features\":[\"sink\",\"std\"],\"name\":\"futures-util\",\"optional\":false},{\"name\":\"log\"},{\"default_features\":true,\"features\":[],\"name\":\"native-tls-crate\",\"optional\":true,\"package\":\"native-tls\"},{\"default_features\":false,\"features\":[],\"name\":\"rustls\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"rustls-native-certs\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"rustls-pki-types\",\"optional\":true},{\"default_features\":false,\"features\":[\"io-util\"],\"name\":\"tokio\",\"optional\":false},{\"default_features\":true,\"features\":[],\"name\":\"tokio-native-tls\",\"optional\":true},{\"default_features\":false,\"features\":[],\"name\":\"tokio-rustls\",\"optional\":true},{\"default_features\":false,\"features\":[],\"name\":\"tungstenite\",\"optional\":false},{\"default_features\":true,\"features\":[],\"name\":\"webpki-roots\",\"optional\":true}],\"features\":{\"__rustls-tls\":[\"rustls\",\"rustls-pki-types\",\"tokio-rustls\",\"stream\",\"tungstenite/__rustls-tls\",\"handshake\"],\"connect\":[\"stream\",\"tokio/net\",\"handshake\"],\"default\":[\"connect\",\"handshake\"],\"handshake\":[\"tungstenite/handshake\"],\"native-tls\":[\"native-tls-crate\",\"tokio-native-tls\",\"stream\",\"tungstenite/native-tls\",\"handshake\"],\"native-tls-vendored\":[\"native-tls\",\"native-tls-crate/vendored\",\"tungstenite/native-tls-vendored\"],\"proxy\":[\"tungstenite/proxy\",\"tokio/net\",\"handshake\"],\"rustls-tls-native-roots\":[\"__rustls-tls\",\"rustls-native-certs\"],\"rustls-tls-webpki-roots\":[\"__rustls-tls\",\"webpki-roots\"],\"stream\":[],\"url\":[\"tungstenite/url\"]},\"strip_prefix\":\"\"}",
       "git+https://github.com/JakkuSakura/tungstenite-rs?rev=f514de8644821113e5d18a027d6d28a5c8cc0a6e#f514de8644821113e5d18a027d6d28a5c8cc0a6e_tungstenite": "{\"dependencies\":[{\"name\":\"bytes\"},{\"default_features\":true,\"features\":[],\"name\":\"data-encoding\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"http\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"httparse\",\"optional\":true},{\"name\":\"log\"},{\"default_features\":true,\"features\":[],\"name\":\"native-tls-crate\",\"optional\":true,\"package\":\"native-tls\"},{\"name\":\"rand\"},{\"default_features\":false,\"features\":[\"std\"],\"name\":\"rustls\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"rustls-native-certs\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"rustls-pki-types\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"sha1\",\"optional\":true},{\"name\":\"thiserror\"},{\"default_features\":true,\"features\":[],\"name\":\"url\",\"optional\":true},{\"name\":\"utf-8\"},{\"default_features\":true,\"features\":[],\"name\":\"webpki-roots\",\"optional\":true}],\"features\":{\"__rustls-tls\":[\"rustls\",\"rustls-pki-types\"],\"default\":[\"handshake\"],\"handshake\":[\"data-encoding\",\"http\",\"httparse\",\"sha1\"],\"native-tls\":[\"native-tls-crate\"],\"native-tls-vendored\":[\"native-tls\",\"native-tls-crate/vendored\"],\"proxy\":[\"handshake\"],\"rustls-tls-native-roots\":[\"__rustls-tls\",\"rustls-native-certs\"],\"rustls-tls-webpki-roots\":[\"__rustls-tls\",\"webpki-roots\"],\"url\":[\"dep:url\"]},\"strip_prefix\":\"\"}",
+      "git+https://github.com/dzbarsky/rules_rust?rev=b56cbaa8465e74127f1ea216f813cd377295ad81#b56cbaa8465e74127f1ea216f813cd377295ad81_runfiles": "{\"dependencies\":[],\"features\":{},\"strip_prefix\":\"\"}",
       "git+https://github.com/helix-editor/nucleo.git?rev=4253de9faabb4e5c6d81d946a5e35a90f87347ee#4253de9faabb4e5c6d81d946a5e35a90f87347ee_nucleo": "{\"dependencies\":[{\"default_features\":true,\"features\":[],\"name\":\"nucleo-matcher\",\"optional\":false},{\"default_features\":true,\"features\":[\"send_guard\",\"arc_lock\"],\"name\":\"parking_lot\",\"optional\":false},{\"name\":\"rayon\"}],\"features\":{},\"strip_prefix\":\"\"}",
       "git+https://github.com/helix-editor/nucleo.git?rev=4253de9faabb4e5c6d81d946a5e35a90f87347ee#4253de9faabb4e5c6d81d946a5e35a90f87347ee_nucleo-matcher": "{\"dependencies\":[{\"name\":\"memchr\"},{\"default_features\":true,\"features\":[],\"name\":\"unicode-segmentation\",\"optional\":true}],\"features\":{\"default\":[\"unicode-normalization\",\"unicode-casefold\",\"unicode-segmentation\"],\"unicode-casefold\":[],\"unicode-normalization\":[],\"unicode-segmentation\":[\"dep:unicode-segmentation\"]},\"strip_prefix\":\"matcher\"}",
       "git+https://github.com/nornagon/crossterm?branch=nornagon%2Fcolor-query#87db8bfa6dc99427fd3b071681b07fc31c6ce995_crossterm": "{\"dependencies\":[{\"default_features\":true,\"features\":[],\"name\":\"bitflags\",\"optional\":false},{\"default_features\":false,\"features\":[],\"name\":\"futures-core\",\"optional\":true},{\"name\":\"parking_lot\"},{\"default_features\":true,\"features\":[\"derive\"],\"name\":\"serde\",\"optional\":true},{\"default_features\":true,\"features\":[],\"name\":\"filedescriptor\",\"optional\":true,\"target\":\"cfg(unix)\"},{\"default_features\":false,\"features\":[],\"name\":\"libc\",\"optional\":true,\"target\":\"cfg(unix)\"},{\"default_features\":true,\"features\":[\"os-poll\"],\"name\":\"mio\",\"optional\":true,\"target\":\"cfg(unix)\"},{\"default_features\":false,\"features\":[\"std\",\"stdio\",\"termios\"],\"name\":\"rustix\",\"optional\":false,\"target\":\"cfg(unix)\"},{\"default_features\":true,\"features\":[],\"name\":\"signal-hook\",\"optional\":true,\"target\":\"cfg(unix)\"},{\"default_features\":true,\"features\":[\"support-v1_0\"],\"name\":\"signal-hook-mio\",\"optional\":true,\"target\":\"cfg(unix)\"},{\"default_features\":true,\"features\":[],\"name\":\"crossterm_winapi\",\"optional\":true,\"target\":\"cfg(windows)\"},{\"default_features\":true,\"features\":[\"winuser\",\"winerror\"],\"name\":\"winapi\",\"optional\":true,\"target\":\"cfg(windows)\"}],\"features\":{\"bracketed-paste\":[],\"default\":[\"bracketed-paste\",\"windows\",\"events\"],\"event-stream\":[\"dep:futures-core\",\"events\"],\"events\":[\"dep:mio\",\"dep:signal-hook\",\"dep:signal-hook-mio\"],\"serde\":[\"dep:serde\",\"bitflags/serde\"],\"use-dev-tty\":[\"filedescriptor\",\"rustix/process\"],\"windows\":[\"dep:winapi\",\"dep:crossterm_winapi\"]},\"strip_prefix\":\"\"}",

codex-rs/Cargo.lock

@@ -1975,7 +1975,7 @@ name = "codex-utils-cargo-bin"
 version = "0.0.0"
 dependencies = [
  "assert_cmd",
- "path-absolutize",
+ "runfiles",
  "thiserror 2.0.17",
 ]
 
@@ -6592,6 +6592,11 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "runfiles"
+version = "0.1.0"
+source = "git+https://github.com/dzbarsky/rules_rust?rev=b56cbaa8465e74127f1ea216f813cd377295ad81#b56cbaa8465e74127f1ea216f813cd377295ad81"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.25"

codex-rs/Cargo.toml

@@ -186,6 +186,7 @@ regex = "1.12.2"
 regex-lite = "0.1.8"
 reqwest = "0.12"
 rmcp = { version = "0.12.0", default-features = false }
+runfiles = { git = "https://github.com/dzbarsky/rules_rust", rev = "b56cbaa8465e74127f1ea216f813cd377295ad81" }
 schemars = "0.8.22"
 seccompiler = "0.5.0"
 sentry = "0.46.0"

codex-rs/core/tests/suite/cli_stream.rs

@@ -16,7 +16,7 @@ use wiremock::matchers::path;
 
 fn repo_root() -> std::path::PathBuf {
     #[expect(clippy::expect_used)]
-    find_resource!(".").expect("failed to resolve repo root")
+    codex_utils_cargo_bin::repo_root().expect("failed to resolve repo root")
 }
 
 fn cli_responses_fixture() -> std::path::PathBuf {

codex-rs/exec/tests/suite/auth_env.rs

@@ -1,5 +1,4 @@
 #![allow(clippy::unwrap_used, clippy::expect_used)]
-use codex_utils_cargo_bin::find_resource;
 use core_test_support::responses::ev_completed;
 use core_test_support::responses::mount_sse_once_match;
 use core_test_support::responses::sse;
@@ -11,7 +10,7 @@ use wiremock::matchers::header;
 async fn exec_uses_codex_api_key_env_var() -> anyhow::Result<()> {
     let test = test_codex_exec();
     let server = start_mock_server().await;
-    let repo_root = find_resource!(".")?;
+    let repo_root = codex_utils_cargo_bin::repo_root()?;
 
     mount_sse_once_match(
         &server,

codex-rs/exec/tests/suite/resume.rs

@@ -113,7 +113,7 @@ fn exec_fixture() -> anyhow::Result<std::path::PathBuf> {
 }
 
 fn exec_repo_root() -> anyhow::Result<std::path::PathBuf> {
-    Ok(find_resource!(".")?)
+    Ok(codex_utils_cargo_bin::repo_root()?)
 }
 
 #[test]

codex-rs/utils/cargo-bin/BUILD.bazel

@@ -3,4 +3,10 @@ load("//:defs.bzl", "codex_rust_crate")
 codex_rust_crate(
     name = "cargo-bin",
     crate_name = "codex_utils_cargo_bin",
+    compile_data = ["repo_root.marker"],
+    lib_data_extra = ["repo_root.marker"],
+    test_data_extra = ["repo_root.marker"],
+    rustc_env = {
+        "CODEX_REPO_ROOT_MARKER": "$(rlocationpath :repo_root.marker)",
+    },
 )

codex-rs/utils/cargo-bin/Cargo.toml

@@ -9,5 +9,5 @@ workspace = true
 
 [dependencies]
 assert_cmd = { workspace = true }
-path-absolutize = { workspace = true }
+runfiles = { workspace = true }
 thiserror = { workspace = true }

codex-rs/utils/cargo-bin/README.md

@@ -0,0 +1,20 @@
+# codex-utils-cargo-bin runfiles strategy
+
+We disable the directory-based runfiles strategy and rely on the manifest
+strategy across all platforms. This avoids Windows path length issues and keeps
+behavior consistent in local and remote builds on all platforms. Bazel sets
+`RUNFILES_MANIFEST_FILE`, and the `codex-utils-cargo-bin` helpers use the
+`runfiles` crate to resolve runfiles via that manifest.
+
+Function behavior:
+- `cargo_bin`: reads `CARGO_BIN_EXE_*` environment variables (set by Cargo or
+  Bazel) and resolves them via the runfiles manifest when `RUNFILES_MANIFEST_FILE`
+  is present. When not under runfiles, it only accepts absolute paths from
+  `CARGO_BIN_EXE_*` and returns an error otherwise.
+- `find_resource!`: used by tests to locate fixtures. It chooses the Bazel
+  runfiles resolution path when `RUNFILES_MANIFEST_FILE` is set, otherwise it
+  falls back to a `CARGO_MANIFEST_DIR`-relative path for Cargo runs.
+
+Background:
+- https://bazel.build/docs/runfiles
+- https://bazel.build/docs/runfiles#runfiles-manifest

codex-rs/utils/cargo-bin/repo_root.marker

@@ -0,0 +1 @@
+

codex-rs/utils/cargo-bin/src/lib.rs

@@ -1,7 +1,12 @@
 use std::ffi::OsString;
+use std::io;
+use std::path::Path;
 use std::path::PathBuf;
 
-pub use path_absolutize;
+pub use runfiles;
+
+/// Bazel sets this when runfiles directories are disabled, which we do on all platforms for consistency.
+const RUNFILES_MANIFEST_ONLY_ENV: &str = "RUNFILES_MANIFEST_ONLY";
 
 #[derive(Debug, thiserror::Error)]
 pub enum CargoBinError {
@@ -27,10 +32,9 @@ pub enum CargoBinError {
 
 /// Returns an absolute path to a binary target built for the current test run.
 ///
-/// In `cargo test`, `CARGO_BIN_EXE_*` env vars are absolute, but Buck2 may set
+/// In `cargo test`, `CARGO_BIN_EXE_*` env vars are absolute.
-/// them to project-relative paths (e.g. `buck-out/...`). Those paths break if a
+/// In `bazel test`, `CARGO_BIN_EXE_*` env vars are rlocationpaths, intended to be consumed by `rlocation`.
-/// test later changes its working directory. This helper makes the path
+/// This helper allows callers to transparently support both.
-/// absolute up-front so callers can safely `chdir` afterwards.
 pub fn cargo_bin(name: &str) -> Result<PathBuf, CargoBinError> {
     let env_keys = cargo_bin_env_keys(name);
     for key in &env_keys {
@@ -38,16 +42,20 @@ pub fn cargo_bin(name: &str) -> Result<PathBuf, CargoBinError> {
             return resolve_bin_from_env(key, value);
         }
     }
-
     match assert_cmd::Command::cargo_bin(name) {
         Ok(cmd) => {
-            let abs = absolutize_from_buck_or_cwd(PathBuf::from(cmd.get_program()))?;
+            let mut path = PathBuf::from(cmd.get_program());
-            if abs.exists() {
+            if !path.is_absolute() {
-                Ok(abs)
+                path = std::env::current_dir()
+                    .map_err(|source| CargoBinError::CurrentDir { source })?
+                    .join(path);
+            }
+            if path.exists() {
+                Ok(path)
             } else {
                 Err(CargoBinError::ResolvedPathDoesNotExist {
                     key: "assert_cmd::Command::cargo_bin".to_owned(),
-                    path: abs,
+                    path,
                 })
             }
         }
@@ -72,6 +80,31 @@ fn cargo_bin_env_keys(name: &str) -> Vec<String> {
     keys
 }
 
+pub fn runfiles_available() -> bool {
+    std::env::var_os(RUNFILES_MANIFEST_ONLY_ENV).is_some()
+}
+
+fn resolve_bin_from_env(key: &str, value: OsString) -> Result<PathBuf, CargoBinError> {
+    let raw = PathBuf::from(&value);
+    if runfiles_available() {
+        let runfiles = runfiles::Runfiles::create().map_err(|err| CargoBinError::CurrentExe {
+            source: std::io::Error::other(err),
+        })?;
+        if let Some(resolved) = runfiles::rlocation!(runfiles, &raw)
+            && resolved.exists()
+        {
+            return Ok(resolved);
+        }
+    } else if raw.is_absolute() && raw.exists() {
+        return Ok(raw);
+    }
+
+    Err(CargoBinError::ResolvedPathDoesNotExist {
+        key: key.to_owned(),
+        path: raw,
+    })
+}
+
 /// Macro that derives the path to a test resource at runtime, the value of
 /// which depends on whether Cargo or Bazel is being used to build and run a
 /// test. Note the return value may be a relative or absolute path.
@@ -84,97 +117,109 @@ fn cargo_bin_env_keys(name: &str) -> Vec<String> {
 #[macro_export]
 macro_rules! find_resource {
     ($resource:expr) => {{
-        // When this code is built and run with Bazel:
-        // - we inject `BAZEL_PACKAGE` as a compile-time environment variable
-        //   that points to native.package_name()
-        // - at runtime, Bazel will set `RUNFILES_DIR` to the runfiles directory
-        //
-        // Therefore, the compile-time value of `BAZEL_PACKAGE` will always be
-        // included in the compiled binary (even if it is built with Cargo), but
-        // we only check it at runtime if `RUNFILES_DIR` is set.
         let resource = std::path::Path::new(&$resource);
-        match std::env::var("RUNFILES_DIR") {
+        if $crate::runfiles_available() {
-            Ok(bazel_runtime_files) => match option_env!("BAZEL_PACKAGE") {
+            // When this code is built and run with Bazel:
-                Some(bazel_package) => {
+            // - we inject `BAZEL_PACKAGE` as a compile-time environment variable
-                    use $crate::path_absolutize::Absolutize;
+            //   that points to native.package_name()
-
+            // - at runtime, Bazel will set runfiles-related env vars
-                    let manifest_dir = std::path::PathBuf::from(bazel_runtime_files)
+            $crate::resolve_bazel_runfile(option_env!("BAZEL_PACKAGE"), resource)
-                        .join("_main")
+        } else {
-                        .join(bazel_package)
+            let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
-                        .join(resource);
+            Ok(manifest_dir.join(resource))
-                    // Note we also have to normalize (but not canonicalize!)
-                    // the path for _Bazel_ because the original value ends with
-                    // `codex-rs/exec-server/tests/common/../suite/bash`, but
-                    // the `tests/common` folder will not exist at runtime under
-                    // Bazel. As such, we have to normalize it before passing it
-                    // to `dotslash fetch`.
-                    manifest_dir.absolutize().map(|p| p.to_path_buf())
-                }
-                None => Err(std::io::Error::new(
-                    std::io::ErrorKind::NotFound,
-                    "BAZEL_PACKAGE not set in Bazel build",
-                )),
-            },
-            Err(_) => {
-                let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
-                Ok(manifest_dir.join(resource))
-            }
         }
     }};
 }
 
-fn resolve_bin_from_env(key: &str, value: OsString) -> Result<PathBuf, CargoBinError> {
+pub fn resolve_bazel_runfile(
-    let abs = absolutize_from_buck_or_cwd(PathBuf::from(value))?;
+    bazel_package: Option<&str>,
-
+    resource: &Path,
-    if abs.exists() {
+) -> std::io::Result<PathBuf> {
-        Ok(abs)
+    let runfiles = runfiles::Runfiles::create()
-    } else {
+        .map_err(|err| std::io::Error::other(format!("failed to create runfiles: {err}")))?;
-        Err(CargoBinError::ResolvedPathDoesNotExist {
+    let runfile_path = match bazel_package {
-            key: key.to_owned(),
+        Some(bazel_package) => PathBuf::from("_main").join(bazel_package).join(resource),
-            path: abs,
+        None => {
-        })
+            return Err(std::io::Error::new(
-    }
+                std::io::ErrorKind::NotFound,
-}
+                "BAZEL_PACKAGE was not set at compile time",
-
+            ));
-fn absolutize_from_buck_or_cwd(path: PathBuf) -> Result<PathBuf, CargoBinError> {
+        }
-    if path.is_absolute() {
+    };
-        return Ok(path);
+    let runfile_path = normalize_runfile_path(&runfile_path);
-    }
+    if let Some(resolved) = runfiles::rlocation!(runfiles, &runfile_path)
-
+        && resolved.exists()
-    if let Some(root) =
-        buck_project_root().map_err(|source| CargoBinError::CurrentExe { source })?
     {
-        return Ok(root.join(path));
+        return Ok(resolved);
     }
-
+    let runfile_path_display = runfile_path.display();
-    Ok(std::env::current_dir()
+    Err(std::io::Error::new(
-        .map_err(|source| CargoBinError::CurrentDir { source })?
+        std::io::ErrorKind::NotFound,
-        .join(path))
+        format!("runfile does not exist at: {runfile_path_display}"),
+    ))
 }
 
-/// Best-effort attempt to find the Buck project root for the currently running
+pub fn resolve_cargo_runfile(resource: &Path) -> std::io::Result<PathBuf> {
-/// process.
+    let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
-///
+    Ok(manifest_dir.join(resource))
-/// Prefer this over `env!("CARGO_MANIFEST_DIR")` when running under Buck2: our
+}
-/// Buck generator sets `CARGO_MANIFEST_DIR="."` for compilation, which makes
+
-/// `env!("CARGO_MANIFEST_DIR")` unusable for locating workspace files.
+pub fn repo_root() -> io::Result<PathBuf> {
-pub fn buck_project_root() -> Result<Option<PathBuf>, std::io::Error> {
+    let marker = if runfiles_available() {
-    if let Some(root) = std::env::var_os("BUCK_PROJECT_ROOT") {
+        let runfiles = runfiles::Runfiles::create()
-        let root = PathBuf::from(root);
+            .map_err(|err| io::Error::other(format!("failed to create runfiles: {err}")))?;
-        if root.is_absolute() {
+        let marker_path = option_env!("CODEX_REPO_ROOT_MARKER")
-            return Ok(Some(root));
+            .map(PathBuf::from)
+            .ok_or_else(|| {
+                io::Error::new(
+                    io::ErrorKind::NotFound,
+                    "CODEX_REPO_ROOT_MARKER was not set at compile time",
+                )
+            })?;
+        runfiles::rlocation!(runfiles, &marker_path).ok_or_else(|| {
+            io::Error::new(
+                io::ErrorKind::NotFound,
+                "repo_root.marker not available in runfiles",
+            )
+        })?
+    } else {
+        resolve_cargo_runfile(Path::new("repo_root.marker"))?
+    };
+    let mut root = marker;
+    for _ in 0..4 {
+        root = root
+            .parent()
+            .ok_or_else(|| {
+                io::Error::new(
+                    io::ErrorKind::NotFound,
+                    "repo_root.marker did not have expected parent depth",
+                )
+            })?
+            .to_path_buf();
+    }
+    Ok(root)
+}
+
+fn normalize_runfile_path(path: &Path) -> PathBuf {
+    let mut components = Vec::new();
+    for component in path.components() {
+        match component {
+            std::path::Component::CurDir => {}
+            std::path::Component::ParentDir => {
+                if matches!(components.last(), Some(std::path::Component::Normal(_))) {
+                    components.pop();
+                } else {
+                    components.push(component);
+                }
+            }
+            _ => components.push(component),
         }
     }
 
-    // Fall back to deriving the project root from the location of the test
+    components
-    // runner executable:
+        .into_iter()
-    //   <project>/buck-out/v2/gen/.../__tests__/test-binary
+        .fold(PathBuf::new(), |mut acc, component| {
-    let exe = std::env::current_exe()?;
+            acc.push(component.as_os_str());
-    for ancestor in exe.ancestors() {
+            acc
-        if ancestor.file_name().is_some_and(|name| name == "buck-out") {
+        })
-            return Ok(ancestor.parent().map(PathBuf::from));
-        }
-    }
-
-    Ok(None)
 }

defs.bzl

@@ -36,6 +36,8 @@ def codex_rust_crate(
         crate_edition = None,
         build_script_data = [],
         compile_data = [],
+        lib_data_extra = [],
+        rustc_env = {},
         deps_extra = [],
         integration_deps_extra = [],
         integration_compile_data_extra = [],
@@ -63,6 +65,8 @@ def codex_rust_crate(
             You probably don't want this, it's only here for a single caller.
         build_script_data: Data files exposed to the build script at runtime.
         compile_data: Non-Rust compile-time data for the library target.
+        lib_data_extra: Extra runtime data for the library target.
+        rustc_env: Extra rustc_env entries to merge with defaults.
         deps_extra: Extra normal deps beyond @crates resolution.
             Typically only needed when features add additional deps.
         integration_deps_extra: Extra deps for integration tests only.
@@ -85,7 +89,7 @@ def codex_rust_crate(
 
     rustc_env = {
         "BAZEL_PACKAGE": native.package_name(),
-    }
+    } | rustc_env
 
     binaries = DEP_DATA.get(native.package_name())["binaries"]
 
@@ -112,6 +116,7 @@ def codex_rust_crate(
             deps = deps,
             proc_macro_deps = proc_macro_deps,
             compile_data = compile_data,
+            data = lib_data_extra,
             srcs = lib_srcs,
             edition = crate_edition,
             rustc_env = rustc_env,
@@ -138,7 +143,7 @@ def codex_rust_crate(
     for binary, main in binaries.items():
         #binary = binary.replace("-", "_")
         sanitized_binaries.append(binary)
-        cargo_env["CARGO_BIN_EXE_" + binary] = "$(rootpath :%s)" % binary
+        cargo_env["CARGO_BIN_EXE_" + binary] = "$(rlocationpath :%s)" % binary
 
         rust_binary(
             name = binary,
@@ -154,7 +159,7 @@ def codex_rust_crate(
     for binary_label in extra_binaries:
         sanitized_binaries.append(binary_label)
         binary = Label(binary_label).name
-        cargo_env["CARGO_BIN_EXE_" + binary] = "$(rootpath %s)" % binary_label
+        cargo_env["CARGO_BIN_EXE_" + binary] = "$(rlocationpath %s)" % binary_label
 
     for test in native.glob(["tests/*.rs"], allow_empty = True):
         test_name = name + "-" + test.removeprefix("tests/").removesuffix(".rs").replace("/", "-")

patches/rules_rust.patch

@@ -31,4 +31,4 @@ index a28ad50b7..af627fe50 100644
 +        make_link_flags = _make_link_flags_default_direct if use_direct_link_driver else _make_link_flags_default_indirect
  
      return (make_link_flags, get_lib_name)
- 
+