From d9b7aefd343c98e9bbc6b1e89b49596c48e19cd5 Mon Sep 17 00:00:00 2001
From: Reinier Criel <reinier.criel@gmail.com>
Date: Wed, 13 May 2026 14:33:58 -0700
Subject: [PATCH] unset PKG_EXECPATH before invoking safe-chain binary

---
 packages/safe-chain/bin/safe-chain.js         |  6 ++
 .../templates/unix-wrapper.template.sh        |  5 +-
 .../pkg-execpath-cleanup.spec.js              | 60 +++++++++++++++++++
 .../startup-scripts/init-fish.fish            |  6 +-
 .../startup-scripts/init-posix.sh             |  6 +-
 5 files changed, 78 insertions(+), 5 deletions(-)
 create mode 100644 packages/safe-chain/src/shell-integration/pkg-execpath-cleanup.spec.js

diff --git a/packages/safe-chain/bin/safe-chain.js b/packages/safe-chain/bin/safe-chain.js
index 900bd83..53b6617 100755
--- a/packages/safe-chain/bin/safe-chain.js
+++ b/packages/safe-chain/bin/safe-chain.js
@@ -1,5 +1,11 @@
 #!/usr/bin/env node
 
+// Strip PKG_EXECPATH from the environment so any child process safe-chain
+// spawns (npm, uv, pip, …) doesn't inherit it. If it leaks into a subsequent
+// safe-chain invocation (e.g. via a shim) the yao-pkg bootstrap would treat
+// argv[1] as a script path and fail with MODULE_NOT_FOUND.
+delete process.env.PKG_EXECPATH;
+
 import chalk from "chalk";
 import { ui } from "../src/environment/userInteraction.js";
 import { setup } from "../src/shell-integration/setup.js";
diff --git a/packages/safe-chain/src/shell-integration/path-wrappers/templates/unix-wrapper.template.sh b/packages/safe-chain/src/shell-integration/path-wrappers/templates/unix-wrapper.template.sh
index 5b318ff..30ab833 100644
--- a/packages/safe-chain/src/shell-integration/path-wrappers/templates/unix-wrapper.template.sh
+++ b/packages/safe-chain/src/shell-integration/path-wrappers/templates/unix-wrapper.template.sh
@@ -20,7 +20,10 @@ remove_shim_from_path() {
 }
 
 if command -v safe-chain >/dev/null 2>&1; then
-  # Remove shim directory from PATH when calling {{AIKIDO_COMMAND}} to prevent infinite loops
+  # Remove shim directory from PATH when calling {{AIKIDO_COMMAND}} to prevent infinite loops.
+  # Unset PKG_EXECPATH so the yao-pkg bootstrap inside the safe-chain binary doesn't
+  # mistake argv[1] for a script path and try to resolve "{{PACKAGE_MANAGER}}" against cwd.
+  unset PKG_EXECPATH
   PATH=$(remove_shim_from_path) exec safe-chain {{PACKAGE_MANAGER}} "$@"
 else
   # safe-chain is not reachable — warn the user so they know protection is inactive
diff --git a/packages/safe-chain/src/shell-integration/pkg-execpath-cleanup.spec.js b/packages/safe-chain/src/shell-integration/pkg-execpath-cleanup.spec.js
new file mode 100644
index 0000000..4057224
--- /dev/null
+++ b/packages/safe-chain/src/shell-integration/pkg-execpath-cleanup.spec.js
@@ -0,0 +1,60 @@
+import { describe, it } from "node:test";
+import assert from "node:assert";
+import fs from "node:fs";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const repoRoot = path.resolve(__dirname, "..", "..");
+
+describe("PKG_EXECPATH cleanup", () => {
+  it("unix shim template unsets PKG_EXECPATH before invoking safe-chain", () => {
+    const file = path.join(
+      repoRoot,
+      "src/shell-integration/path-wrappers/templates/unix-wrapper.template.sh",
+    );
+    const content = fs.readFileSync(file, "utf-8");
+    assert.match(
+      content,
+      /unset PKG_EXECPATH[\s\S]*exec safe-chain/,
+      "unix-wrapper.template.sh must `unset PKG_EXECPATH` before `exec safe-chain`",
+    );
+  });
+
+  it("posix shell function unsets PKG_EXECPATH before invoking safe-chain", () => {
+    const file = path.join(
+      repoRoot,
+      "src/shell-integration/startup-scripts/init-posix.sh",
+    );
+    const content = fs.readFileSync(file, "utf-8");
+    // Scoped subshell so we don't mutate the user's interactive env.
+    assert.match(
+      content,
+      /\(unset PKG_EXECPATH;\s*safe-chain "\$@"\)/,
+      "init-posix.sh must invoke safe-chain in a subshell that unsets PKG_EXECPATH",
+    );
+  });
+
+  it("fish shell function unsets PKG_EXECPATH before invoking safe-chain", () => {
+    const file = path.join(
+      repoRoot,
+      "src/shell-integration/startup-scripts/init-fish.fish",
+    );
+    const content = fs.readFileSync(file, "utf-8");
+    assert.match(
+      content,
+      /env -u PKG_EXECPATH safe-chain/,
+      "init-fish.fish must invoke safe-chain via `env -u PKG_EXECPATH`",
+    );
+  });
+
+  it("safe-chain entry point deletes PKG_EXECPATH from process.env", () => {
+    const file = path.join(repoRoot, "bin/safe-chain.js");
+    const content = fs.readFileSync(file, "utf-8");
+    assert.match(
+      content,
+      /delete process\.env\.PKG_EXECPATH/,
+      "bin/safe-chain.js must delete process.env.PKG_EXECPATH so spawned children don't inherit it",
+    );
+  });
+});
diff --git a/packages/safe-chain/src/shell-integration/startup-scripts/init-fish.fish b/packages/safe-chain/src/shell-integration/startup-scripts/init-fish.fish
index 728aff1..68a3df0 100644
--- a/packages/safe-chain/src/shell-integration/startup-scripts/init-fish.fish
+++ b/packages/safe-chain/src/shell-integration/startup-scripts/init-fish.fish
@@ -120,8 +120,10 @@ function wrapSafeChainCommand
     end
 
     if type -q safe-chain
-        # If the safe-chain command is available, just run it with the provided arguments
-        safe-chain $original_cmd $cmd_args
+        # If the safe-chain command is available, just run it with the provided arguments.
+        # Unset PKG_EXECPATH for this invocation so the yao-pkg bootstrap inside the
+        # safe-chain binary doesn't mistake argv[1] for a script path to resolve against cwd.
+        env -u PKG_EXECPATH safe-chain $original_cmd $cmd_args
     else
         # If the safe-chain command is not available, print a warning and run the original command
         printSafeChainWarning $original_cmd
diff --git a/packages/safe-chain/src/shell-integration/startup-scripts/init-posix.sh b/packages/safe-chain/src/shell-integration/startup-scripts/init-posix.sh
index cde8f48..258c281 100644
--- a/packages/safe-chain/src/shell-integration/startup-scripts/init-posix.sh
+++ b/packages/safe-chain/src/shell-integration/startup-scripts/init-posix.sh
@@ -109,8 +109,10 @@ function wrapSafeChainCommand() {
   fi
 
   if command -v safe-chain > /dev/null 2>&1; then
-    # If the aikido command is available, just run it with the provided arguments
-    safe-chain "$@"
+    # If the aikido command is available, just run it with the provided arguments.
+    # Unset PKG_EXECPATH so the yao-pkg bootstrap inside the safe-chain binary doesn't
+    # mistake argv[1] for a script path and try to resolve it against cwd.
+    (unset PKG_EXECPATH; safe-chain "$@")
   else
     # If the aikido command is not available, print a warning and run the original command
     printSafeChainWarning "$original_cmd"