From edd9a024eb637941efd7c32462c7b2af07336124 Mon Sep 17 00:00:00 2001
From: Miles Johnson <milesj@users.noreply.github.com>
Date: Mon, 1 Jul 2024 15:43:16 -0700
Subject: [PATCH] fix: Respect `CARGO_HOME` during rustup install. (#29)

---
 CHANGELOG.md   |  6 ++++++
 Cargo.lock     |  2 +-
 Cargo.toml     |  2 +-
 src/helpers.rs | 40 +++++++++++++++++++++++++++-------------
 src/proto.rs   |  9 ++++++---
 5 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f568a49..35e6e57 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.10.4
+
+#### 🐞 Fixes
+
+- Updated our "automatic rustup installation" to respect the `CARGO_HOME` environment variable.
+
 ## 0.10.3
 
 #### 🚀 Updates
diff --git a/Cargo.lock b/Cargo.lock
index 025cbd5..0d1da9e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2384,7 +2384,7 @@ dependencies = [
 
 [[package]]
 name = "rust_plugin"
-version = "0.10.3"
+version = "0.10.4"
 dependencies = [
  "extism-pdk",
  "proto_pdk",
diff --git a/Cargo.toml b/Cargo.toml
index dc9d7cb..32d2bcd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rust_plugin"
-version = "0.10.3"
+version = "0.10.4"
 edition = "2021"
 license = "MIT"
 publish = false
diff --git a/src/helpers.rs b/src/helpers.rs
index cd9a71d..06e6bb6 100644
--- a/src/helpers.rs
+++ b/src/helpers.rs
@@ -9,26 +9,40 @@ extern "ExtismHost" {
     fn to_virtual_path(input: String) -> String;
 }
 
-pub fn get_rustup_home(env: &HostEnvironment) -> Result<VirtualPath, Error> {
-    // Cargo sets the RUSTUP_HOME env var when running tests,
-    // which causes a ton of issues, so intercept it here!
-    if let Some(test_env) = get_test_environment()? {
-        return Ok(virtual_path!(buf, test_env.sandbox).join(".home/.rustup"));
-    }
+fn get_home_env(key: &str) -> Result<Option<VirtualPath>, Error> {
+    match host_env!(key) {
+        Some(value) => {
+            if value.is_empty() {
+                return Ok(None);
+            }
 
-    Ok(match host_env!("RUSTUP_HOME") {
-        Some(path) => {
-            let path = PathBuf::from(path);
+            let path = PathBuf::from(value);
 
             // Variable returns a real path, so convert to virtual
-            if path.is_absolute() {
+            let path = if path.is_absolute() {
                 virtual_path!(buf, path)
             } else {
                 virtual_path!("/cwd").join(path)
-            }
+            };
+
+            Ok(Some(path))
         }
-        None => env.home_dir.join(".rustup"),
-    })
+        None => Ok(None),
+    }
+}
+
+pub fn get_cargo_home(env: &HostEnvironment) -> Result<VirtualPath, Error> {
+    Ok(get_home_env("CARGO_HOME")?.unwrap_or_else(|| env.home_dir.join(".cargo")))
+}
+
+pub fn get_rustup_home(env: &HostEnvironment) -> Result<VirtualPath, Error> {
+    // Cargo sets the RUSTUP_HOME env var when running tests,
+    // which causes a ton of issues, so intercept it here!
+    if let Some(test_env) = get_test_environment()? {
+        return Ok(virtual_path!(buf, test_env.sandbox).join(".home/.rustup"));
+    }
+
+    Ok(get_home_env("RUSTUP_HOME")?.unwrap_or_else(|| env.home_dir.join(".rustup")))
 }
 
 pub fn get_channel_from_version(spec: &VersionSpec) -> String {
diff --git a/src/proto.rs b/src/proto.rs
index 08e5610..85f8092 100644
--- a/src/proto.rs
+++ b/src/proto.rs
@@ -40,13 +40,13 @@ pub fn load_versions(Json(_): Json<LoadVersionsInput>) -> FnResult<Json<LoadVers
     let tags = load_git_tags("https://github.com/rust-lang/rust")?;
 
     let tags = tags
-        .iter()
+        .into_iter()
         .filter_map(|tag| {
             // Filter out old versions
             if tag.starts_with("release-") || tag.starts_with("0.") {
                 None
             } else {
-                Some(tag.to_owned())
+                Some(tag)
             }
         })
         .collect::<Vec<_>>();
@@ -144,7 +144,10 @@ pub fn native_install(
 
         // Update PATH explicitly, since we can't "reload the shell"
         // on the host side. This is good enough since it's deterministic.
-        host_env!("PATH", "/userhome/.cargo/bin");
+        host_env!(
+            "PATH",
+            format!("{}:$HOME/.cargo/bin", get_cargo_home(&env)?.join("bin"))
+        );
     }
 
     let version = &input.context.version;