fix: respect OMP config directory override

refs #1696

3 files changed, 51 insertions, 8 deletions

diff --git a/src/integration/env.rs b/src/integration/env.rs
index ef946729..3cd1b604 100644
--- a/src/integration/env.rs
+++ b/src/integration/env.rs
@@ -10,6 +10,7 @@ pub(crate) const HERDR_TAB_ID_ENV_VAR: &str = "HERDR_TAB_ID";
 pub(crate) const HERDR_WORKSPACE_ID_ENV_VAR: &str = "HERDR_WORKSPACE_ID";
 
 pub(crate) const PI_CODING_AGENT_DIR_ENV_VAR: &str = "PI_CODING_AGENT_DIR";
+pub(crate) const OMP_CONFIG_DIR_ENV_VAR: &str = "PI_CONFIG_DIR";
 pub(crate) const CLAUDE_CONFIG_DIR_ENV_VAR: &str = "CLAUDE_CONFIG_DIR";
 pub(crate) const CODEX_HOME_ENV_VAR: &str = "CODEX_HOME";
 pub(crate) const KIMI_CODE_HOME_ENV_VAR: &str = "KIMI_CODE_HOME";
@@ -29,10 +30,19 @@ pub(crate) fn pi_extension_dir() -> io::Result<PathBuf> {
 }
 
 pub(crate) fn omp_extension_dir() -> io::Result<PathBuf> {
-    Ok(
-        config_dir_from_env_or_home(PI_CODING_AGENT_DIR_ENV_VAR, &[".omp", "agent"])?
-            .join("extensions"),
-    )
+    if let Some(value) =
+        std::env::var_os(PI_CODING_AGENT_DIR_ENV_VAR).filter(|value| !value.is_empty())
+    {
+        return expand_tilde_path(PathBuf::from(value)).map(|path| path.join("extensions"));
+    }
+
+    let config_dir = std::env::var_os(OMP_CONFIG_DIR_ENV_VAR)
+        .filter(|value| !value.is_empty())
+        .unwrap_or_else(|| ".omp".into());
+    Ok(home_dir()?
+        .join(config_dir)
+        .join("agent")
+        .join("extensions"))
 }
 
 pub(crate) fn claude_dir() -> io::Result<PathBuf> {
diff --git a/src/integration/targets.rs b/src/integration/targets.rs
index 99c150a3..5d5e730c 100644
--- a/src/integration/targets.rs
+++ b/src/integration/targets.rs
@@ -69,6 +69,13 @@ pub(crate) fn install_pi() -> io::Result<PathBuf> {
 
 pub(crate) fn install_omp() -> io::Result<OmpInstallPaths> {
     let dir = omp_extension_dir()?;
+    let pi_dir = pi_extension_dir()?;
+    if dir == pi_dir {
+        return Err(io::Error::other(format!(
+            "Pi and OMP resolve to the same extension directory at {}; configure separate agent directories before installing OMP",
+            dir.display()
+        )));
+    }
     ensure_extension_dir(&dir, "omp")?;
 
     let removed_legacy_pi_extension = remove_legacy_pi_extension_from_omp_dir(&dir)?;
diff --git a/src/integration/tests.rs b/src/integration/tests.rs
index fc332a84..78b728f9 100644
--- a/src/integration/tests.rs
+++ b/src/integration/tests.rs
@@ -94,6 +94,7 @@ fn enforce_agent_version_accepts_current_version() {
 
 fn clear_integration_path_env() {
     std::env::remove_var(PI_CODING_AGENT_DIR_ENV_VAR);
+    std::env::remove_var(OMP_CONFIG_DIR_ENV_VAR);
     std::env::remove_var(CLAUDE_CONFIG_DIR_ENV_VAR);
     std::env::remove_var(CODEX_HOME_ENV_VAR);
     std::env::remove_var(COPILOT_HOME_ENV_VAR);
@@ -625,13 +626,14 @@ fn install_omp_preserves_non_herdr_file_with_pi_install_name() {
 }
 
 #[test]
-fn install_omp_uses_pi_coding_agent_dir_env() {
+fn install_omp_uses_pi_config_dir_env() {
     let _lock = integration_env_lock();
     let base = unique_base();
-    let agent_dir = base.join("custom-omp-agent");
-    let ext_dir = agent_dir.join("extensions");
+    let home = base.join("home");
+    let ext_dir = home.join("custom-omp/agent/extensions");
     fs::create_dir_all(&ext_dir).unwrap();
-    std::env::set_var(PI_CODING_AGENT_DIR_ENV_VAR, &agent_dir);
+    std::env::set_var("HOME", &home);
+    std::env::set_var(OMP_CONFIG_DIR_ENV_VAR, "custom-omp");
 
     let installed = install_omp().unwrap();
 
@@ -641,6 +643,30 @@ fn install_omp_uses_pi_coding_agent_dir_env() {
     );
     assert!(!installed.removed_legacy_pi_extension);
 
+    std::env::remove_var("HOME");
+    clear_integration_path_env();
+    let _ = fs::remove_dir_all(base);
+}
+
+#[test]
+fn install_omp_refuses_shared_pi_extension_directory() {
+    let _lock = integration_env_lock();
+    let base = unique_base();
+    let agent_dir = base.join("shared-agent");
+    let ext_dir = agent_dir.join("extensions");
+    let pi_extension = ext_dir.join(PI_EXTENSION_INSTALL_NAME);
+    fs::create_dir_all(&ext_dir).unwrap();
+    fs::write(&pi_extension, PI_EXTENSION_ASSET).unwrap();
+    std::env::set_var(PI_CODING_AGENT_DIR_ENV_VAR, &agent_dir);
+    std::env::set_var(OMP_CONFIG_DIR_ENV_VAR, "ignored-omp-config");
+
+    let err = install_omp().unwrap_err().to_string();
+
+    assert!(err.contains("Pi and OMP resolve to the same extension directory"));
+    assert!(err.contains(&ext_dir.display().to_string()));
+    assert!(pi_extension.is_file());
+    assert!(!ext_dir.join(OMP_EXTENSION_INSTALL_NAME).exists());
+
     clear_integration_path_env();
     let _ = fs::remove_dir_all(base);
 }