bunfig: fall back to $HOME/.bunfig.toml when $XDG_CONFIG_HOME has none

src/bunfig/arguments.rs

@@ -17,22 +17,23 @@ use crate::bunfig::Bunfig;
 
 // ─── bunfig loading ──────────────────────────────────────────────────────────
 
+/// `$XDG_CONFIG_HOME/.bunfig.toml` when that file exists, otherwise
+/// `$HOME/.bunfig.toml` (same rule as the user-level `.npmrc` in
+/// `PackageManager::init`). Many desktops and CI runners export
+/// `XDG_CONFIG_HOME` without ever putting a bunfig there.
 fn get_home_config_path(buf: &mut PathBuffer) -> Option<&ZStr> {
     let paths: [&[u8]; 1] = [b".bunfig.toml"];
 
-    if let Some(data_dir) = env_var::XDG_CONFIG_HOME.get() {
-        return Some(resolve_path::join_abs_string_buf_z::<platform::Auto>(
-            data_dir, &mut **buf, &paths,
-        ));
-    }
-
-    if let Some(home_dir) = env_var::HOME.get() {
-        return Some(resolve_path::join_abs_string_buf_z::<platform::Auto>(
-            home_dir, &mut **buf, &paths,
-        ));
-    }
+    let xdg_dir = env_var::XDG_CONFIG_HOME.get_not_empty().filter(|xdg_dir| {
+        bun_sys::exists_z(resolve_path::join_abs_string_buf_z::<platform::Auto>(
+            xdg_dir, &mut **buf, &paths,
+        ))
+    });
+    let dir = xdg_dir.or_else(|| env_var::HOME.get_not_empty())?;
 
-    None
+    Some(resolve_path::join_abs_string_buf_z::<platform::Auto>(
+        dir, &mut **buf, &paths,
+    ))
 }
 
 fn load_bunfig(

test/cli/install/npmrc.test.ts

@@ -2,7 +2,7 @@ import { write } from "bun";
 import { afterAll, beforeAll, describe, expect, it, test } from "bun:test";
 import { rm } from "fs/promises";
 import { VerdaccioRegistry, bunExe, bunEnv as env, tempDir } from "harness";
-import { join } from "path";
+import { basename, join } from "path";
 const { iniInternals } = require("bun:internal-for-testing");
 const { loadNpmrc } = iniInternals;
 
@@ -224,6 +224,67 @@ registry = http://localhost:${registry.port}/
     });
   });
 
+  // The global .bunfig.toml is looked up with the same rule as the user .npmrc above.
+  describe("global .bunfig.toml lookup", () => {
+    const bunfig = (cacheDir: string) => `[install]\ncache = "${cacheDir}"\n`;
+    const pkg = { "pkg/package.json": JSON.stringify({ name: "bunfig-lookup", version: "0.0.1" }) };
+
+    // `bun pm cache` prints the install cache directory. Each candidate .bunfig.toml
+    // points it at a differently named directory, so the output shows which file was
+    // read. BUN_INSTALL_CACHE_DIR would take precedence over bunfig, and CI runners
+    // set it as well as XDG_CONFIG_HOME, so both are removed.
+    async function pmCache(dir: string, envOverride: Record<string, string>) {
+      const spawnEnv = { ...env, HOME: join(dir, "home"), USERPROFILE: join(dir, "home") };
+      delete spawnEnv.XDG_CONFIG_HOME;
+      delete spawnEnv.BUN_INSTALL_CACHE_DIR;
+
+      await using proc = Bun.spawn({
+        cmd: [bunExe(), "pm", "cache"],
+        cwd: join(dir, "pkg"),
+        env: { ...spawnEnv, ...envOverride },
+        stdout: "pipe",
+        stderr: "pipe",
+      });
+      const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+      return { cacheDir: basename(stdout.trim()), stderr, exitCode };
+    }
+
+    const usesCacheDir = (cacheDir: string) => ({ cacheDir, stderr: "", exitCode: 0 });
+
+    it.concurrent("uses $XDG_CONFIG_HOME/.bunfig.toml when it exists", async () => {
+      using dir = tempDir("bunfig-xdg", {
+        ...pkg,
+        "home/.bunfig.toml": bunfig("home-cache"),
+        "xdg/.bunfig.toml": bunfig("xdg-cache"),
+      });
+      const result = await pmCache(String(dir), { XDG_CONFIG_HOME: join(String(dir), "xdg") });
+      expect(result).toEqual(usesCacheDir("xdg-cache"));
+    });
+
+    // https://github.com/oven-sh/bun/issues/23128
+    it.concurrent("falls back to $HOME/.bunfig.toml when $XDG_CONFIG_HOME has no .bunfig.toml", async () => {
+      using dir = tempDir("bunfig-xdg-without-bunfig", {
+        ...pkg,
+        "home/.bunfig.toml": bunfig("home-cache"),
+        "xdg/.keep": "",
+      });
+      const result = await pmCache(String(dir), { XDG_CONFIG_HOME: join(String(dir), "xdg") });
+      expect(result).toEqual(usesCacheDir("home-cache"));
+    });
+
+    it.concurrent("uses $HOME/.bunfig.toml when $XDG_CONFIG_HOME is unset", async () => {
+      using dir = tempDir("bunfig-xdg-unset", { ...pkg, "home/.bunfig.toml": bunfig("home-cache") });
+      const result = await pmCache(String(dir), {});
+      expect(result).toEqual(usesCacheDir("home-cache"));
+    });
+
+    it.concurrent("uses $HOME/.bunfig.toml when $XDG_CONFIG_HOME is empty", async () => {
+      using dir = tempDir("bunfig-xdg-empty", { ...pkg, "home/.bunfig.toml": bunfig("home-cache") });
+      const result = await pmCache(String(dir), { XDG_CONFIG_HOME: "" });
+      expect(result).toEqual(usesCacheDir("home-cache"));
+    });
+  });
+
   it("package config overrides home config", async () => {
     const { packageDir, packageJson } = await registry.createTestDir();