From 489690fa160e9fc362cd3d40d61c1713ca006c47 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <peter@steipete.me>
Date: Tue, 14 Jul 2026 00:43:30 -0700
Subject: [PATCH] fix(process): apply undefined env removals (#107258)

Co-authored-by: Pavan Kumar Gondhi <pavangondhi@gmail.com>
---
 src/process/exec-spawn.ts |  7 ++++---
 src/process/exec.ts       | 36 ------------------------------------
 2 files changed, 4 insertions(+), 39 deletions(-)

diff --git a/src/process/exec-spawn.ts b/src/process/exec-spawn.ts
index 6d8146409a73..b20fc4cabe8c 100644
--- a/src/process/exec-spawn.ts
+++ b/src/process/exec-spawn.ts
@@ -12,9 +12,6 @@ function assignChildEnvValue(params: {
   platform: NodeJS.Platform;
   value: string | undefined;
 }): void {
-  if (params.value === undefined) {
-    return;
-  }
   if (params.platform === "win32") {
     const normalizedKey = params.key.toLowerCase();
     for (const existingKey of Object.keys(params.env)) {
@@ -23,6 +20,10 @@ function assignChildEnvValue(params: {
       }
     }
   }
+  if (params.value === undefined) {
+    delete params.env[params.key];
+    return;
+  }
   params.env[params.key] = params.value;
 }
 
diff --git a/src/process/exec.ts b/src/process/exec.ts
index f0fa044c0f43..4342b31ad360 100644
--- a/src/process/exec.ts
+++ b/src/process/exec.ts
@@ -17,42 +17,6 @@ export type { SpawnResult } from "./exec-result.js";
 export { resolveCommandEnv, shouldSpawnWithShell, spawnCommand } from "./exec-spawn.js";
 export type { SpawnCommandOptions } from "./exec-spawn.js";
 
-function assignChildEnvValue(params: {
-  env: NodeJS.ProcessEnv;
-  key: string;
-  platform: NodeJS.Platform;
-  value: string | undefined;
-}): void {
-  if (params.platform === "win32") {
-    const normalizedKey = params.key.toLowerCase();
-    for (const existingKey of Object.keys(params.env)) {
-      if (existingKey.toLowerCase() === normalizedKey && existingKey !== params.key) {
-        delete params.env[existingKey];
-      }
-    }
-  }
-  if (params.value === undefined) {
-    delete params.env[params.key];
-    return;
-  }
-  params.env[params.key] = params.value;
-}
-
-function mergeChildEnv(params: {
-  baseEnv: NodeJS.ProcessEnv;
-  env?: NodeJS.ProcessEnv;
-  platform: NodeJS.Platform;
-}): NodeJS.ProcessEnv {
-  const resolvedEnv: NodeJS.ProcessEnv = {};
-  for (const [key, value] of Object.entries(params.baseEnv)) {
-    assignChildEnvValue({ env: resolvedEnv, key, platform: params.platform, value });
-  }
-  for (const [key, value] of Object.entries(params.env ?? {})) {
-    assignChildEnvValue({ env: resolvedEnv, key, platform: params.platform, value });
-  }
-  return resolvedEnv;
-}
-
 const DEFAULT_EXEC_MAX_BUFFER_BYTES = 1024 * 1024;
 
 export type RunExecOptions = {