From 2ac031d6fd3cb9b98ffb1801033d96675291f577 Mon Sep 17 00:00:00 2001
From: Leo K <crowlkats@toaxl.com>
Date: Wed, 4 Aug 2021 21:47:43 +0200
Subject: [PATCH] feat(unstable): clean environmental variables for subprocess
 (#11571)

This commit adds "Deno.RunOptions.clearEnv" option, that allows
to clear environmental variables from parent process before spawning
a subprocess.
---
 cli/dts/lib.deno.ns.d.ts       |  4 ++++
 cli/dts/lib.deno.unstable.d.ts |  8 ++++++++
 cli/tests/unit/process_test.ts | 28 ++++++++++++++++++++++++++++
 runtime/js/40_process.js       |  2 ++
 runtime/ops/process.rs         |  6 ++++++
 5 files changed, 48 insertions(+)

diff --git a/cli/dts/lib.deno.ns.d.ts b/cli/dts/lib.deno.ns.d.ts
index 37cc58ad6b..e1aff59fc9 100644
--- a/cli/dts/lib.deno.ns.d.ts
+++ b/cli/dts/lib.deno.ns.d.ts
@@ -2034,6 +2034,10 @@ declare namespace Deno {
    * Subprocess uses same working directory as parent process unless `opt.cwd`
    * is specified.
    *
+   * Environmental variables from parent process can be cleared using `opt.clearEnv`.
+   * Doesn't guarantee that only `opt.env` variables are present,
+   * as the OS may set environmental variables for processes.
+   *
    * Environmental variables for subprocess can be specified using `opt.env`
    * mapping.
    *
diff --git a/cli/dts/lib.deno.unstable.d.ts b/cli/dts/lib.deno.unstable.d.ts
index 0ac8294637..6fbd13f5f2 100644
--- a/cli/dts/lib.deno.unstable.d.ts
+++ b/cli/dts/lib.deno.unstable.d.ts
@@ -791,6 +791,14 @@ declare namespace Deno {
     mtime: number | Date,
   ): Promise<void>;
 
+  export function run<
+    T extends RunOptions & {
+      clearEnv?: boolean;
+    } = RunOptions & {
+      clearEnv?: boolean;
+    },
+  >(opt: T): Process<T>;
+
   /** **UNSTABLE**: The `signo` argument may change to require the Deno.Signal
    * enum.
    *
diff --git a/cli/tests/unit/process_test.ts b/cli/tests/unit/process_test.ts
index 9bb4d7fc20..f187efe71c 100644
--- a/cli/tests/unit/process_test.ts
+++ b/cli/tests/unit/process_test.ts
@@ -510,3 +510,31 @@ unitTest({ perms: { run: true, read: true } }, function killFailed(): void {
 
   p.close();
 });
+
+unitTest(
+  { perms: { run: true, read: true, env: true } },
+  async function clearEnv(): Promise<void> {
+    const p = Deno.run({
+      cmd: [
+        Deno.execPath(),
+        "eval",
+        "-p",
+        "JSON.stringify(Deno.env.toObject())",
+      ],
+      stdout: "piped",
+      clearEnv: true,
+      env: {
+        FOO: "23147",
+      },
+    });
+
+    const obj = JSON.parse(new TextDecoder().decode(await p.output()));
+
+    // can't check for object equality because the OS may set additional env vars for processes
+    // so we check if PATH isn't present as that is a common env var across OS's and isn't set for processes.
+    assertEquals(obj.FOO, "23147");
+    assert(!("PATH" in obj));
+
+    p.close();
+  },
+);
diff --git a/runtime/js/40_process.js b/runtime/js/40_process.js
index 70a590f36d..543c53c271 100644
--- a/runtime/js/40_process.js
+++ b/runtime/js/40_process.js
@@ -100,6 +100,7 @@
   function run({
     cmd,
     cwd = undefined,
+    clearEnv = false,
     env = {},
     stdout = "inherit",
     stderr = "inherit",
@@ -111,6 +112,7 @@
     const res = opRun({
       cmd: ArrayPrototypeMap(cmd, String),
       cwd,
+      clearEnv,
       env: ObjectEntries(env),
       stdin: isRid(stdin) ? "" : stdin,
       stdout: isRid(stdout) ? "" : stdout,
diff --git a/runtime/ops/process.rs b/runtime/ops/process.rs
index 679deff98c..0f0cc6e2a0 100644
--- a/runtime/ops/process.rs
+++ b/runtime/ops/process.rs
@@ -61,6 +61,7 @@ fn subprocess_stdio_map(s: &str) -> Result<std::process::Stdio, AnyError> {
 pub struct RunArgs {
   cmd: Vec<String>,
   cwd: Option<String>,
+  clear_env: bool,
   env: Vec<(String, String)>,
   stdin: String,
   stdout: String,
@@ -113,6 +114,11 @@ fn op_run(
     c.arg(arg);
   });
   cwd.map(|d| c.current_dir(d));
+
+  if run_args.clear_env {
+    super::check_unstable(state, "Deno.run.clearEnv");
+    c.env_clear();
+  }
   for (key, value) in &env {
     c.env(key, value);
   }