feat: set CARGO_INSTALL_ROOT environment variable

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- The `CARGO_INSTALL_ROOT` environment variable is set when running `cargo install`.
+  This allows sub-processed using the `cargo install` command (such as
+  [yazi's build script](https://github.com/sxyazi/yazi/blob/c27ef58116794de7f559bca74e60e6e13ae92051/yazi-build/build.rs#L37))
+  to use the right installation path.
+
 ## [3.3.1] - 2025-06-17
 
 ### Changed

src/index.ts

@@ -49,7 +49,9 @@ async function run(): Promise<void> {
     core.startGroup(
       `No cached version found, installing ${input.crate} using cargo...`,
     );
-    await exec.exec('cargo', install.args);
+
+    const env = { ...process.env, ...install.env } as Record<string, string>;
+    await exec.exec('cargo', install.args, { env });
 
     try {
       await cache.saveCache([install.path], install.cacheKey);

src/install.ts

@@ -12,6 +12,7 @@ export type ResolvedVersion =
 export interface InstallSettings {
   path: string;
   args: string[];
+  env: Record<string, string>;
   cacheKey: string;
 }
 
@@ -29,11 +30,13 @@ export async function getInstallSettings(
 
   const installPath = path.join(homePath, '.cargo-install', input.crate);
   const args = getInstallArgs(input, version, installPath);
+  const env = { CARGO_INSTALL_ROOT: installPath };
   const cacheKey = await getCacheKey(input, version, args);
 
   return {
     path: installPath,
     args,
+    env,
     cacheKey,
   };
 }