[lldb-dap] Running in server mode does not propagate environment variables

[mateusz-plociennik]

Description

When debugging a program that uses std::getenv() with lldb-dap running in server mode,
the call to std::getenv("HOME") unexpectedly returns nullptr.

---

Environment

• VS Code version: 1.103.2
• Extension version: 0.2.16
• lldb-dap version: 21.1.1
• OS version: macOS 15.6.1 (24G90)

---

settings.json

{
    "lldb-dap.serverMode": true,
    "lldb-dap.executable-path": "/opt/homebrew/opt/llvm/bin/lldb-dap"
}

---

Minimal Reproducible Example

main.cpp

#include <cstdlib>
#include <filesystem>
#include <iostream>
#include <stdexcept>

std::filesystem::path getUserHomeFolder()
{
    if (const char* home = std::getenv("HOME"))
        return home;

    throw std::runtime_error("Could not determine user home directory");
}

int main()
{
    std::cout << getUserHomeFolder() << "\n";
    return 0;
}

---

Steps to Reproduce

1. Enable lldb-dap.serverMode in settings.json.
2. Debug the provided main.cpp with lldb-dap.
3. Observe the result of std::getenv("HOME").

---

Expected Behavior

• The debugged process receives all the environment variables as in non-server mode.
• std::getenv("HOME") should return the user’s home directory path.

---

Actual Behavior

std::getenv("HOME") returns nullptr instead.

[llvmbot]

@llvm/issue-subscribers-lldb-dap

Author: Mateusz Płóciennik (mateusz-plociennik)

### Description

When debugging a program that uses std::getenv() with lldb-dap running in server mode,
the call to std::getenv("HOME") unexpectedly returns nullptr.

---

Environment

• VS Code version: 1.103.2
• Extension version: 0.2.16
• lldb-dap version: 21.1.1
• OS version: macOS 15.6.1 (24G90)

---

settings.json

{
    "lldb-dap.serverMode": true,
    "lldb-dap.executable-path": "/opt/homebrew/opt/llvm/bin/lldb-dap"
}

---

Minimal Reproducible Example

main.cpp

#include <cstdlib>
#include <filesystem>
#include <iostream>
#include <stdexcept>

std::filesystem::path getUserHomeFolder()
{
    if (const char* home = std::getenv("HOME"))
        return home;

    throw std::runtime_error("Could not determine user home directory");
}

int main()
{
    std::cout << getUserHomeFolder() << "\n";
    return 0;
}

---

Steps to Reproduce

1. Enable lldb-dap.serverMode in settings.json.
2. Debug the provided main.cpp with lldb-dap.
3. Observe the result of std::getenv("HOME").

---

Expected Behavior

std::getenv("HOME") should return the user’s home directory path.

---

Actual Behavior

std::getenv("HOME") returns nullptr instead.

[mateusz-plociennik]

Only if I run lldb-dab with the following config, then the debugged process will receive the correct $HOME variable.

    "lldb-dap.environment": {
        "HOME": "/Users/mateuszp"
    },

I would expect that the debugged process receives all environment variables as specified in debug config.
Logs from lldb-dap:

2025-09-23 16:59:03.647 [info] Resolving debug configuration for "Debug MyApp"
2025-09-23 16:59:03.663 [info] lldb-dap path: /opt/homebrew/opt/llvm/bin/lldb-dap
2025-09-23 16:59:03.663 [info] lldb-dap args: --connection-timeout 60
2025-09-23 16:59:03.663 [info] cwd: /Users/mateuszp/Developer/sw/MyApp/build/MyApp.app/Contents/MacOS
2025-09-23 16:59:03.663 [info] env: {"HOME":"/Users/mateuszp"}
2025-09-23 16:59:03.806 [info] Resolved debug configuration:
{
  "type": "lldb-dap",
  "name": "Debug MyApp",
  "request": "launch",
  "cwd": "/Users/mateuszp/Developer/sw/MyApp/build/MyApp.app/Contents/MacOS",
  "MIMode": "lldb",
  "miDebuggerPath": "/usr/bin/lldb",
  "program": "/Users/mateuszp/Developer/sw/MyApp/build/MyApp.app/Contents/MacOS/MyApp",
  "environment": [
    {
      "name": "COMMAND_MODE",
      "value": "unix2003"
    },
    {
      "name": "HOME",
      "value": "/Users/mateuszp"
    },
    {
      "name": "HOMEBREW_CELLAR",
      "value": "/opt/homebrew/Cellar"
    },
    {
      "name": "HOMEBREW_PREFIX",
      "value": "/opt/homebrew"
    },
    {
      "name": "HOMEBREW_REPOSITORY",
      "value": "/opt/homebrew"
    },
    {
      "name": "INFOPATH",
      "value": "/opt/homebrew/share/info:"
    },
    {
      "name": "LOGNAME",
      "value": "mateuszp"
    },
    {
      "name": "MallocNanoZone",
      "value": "0"
    },
    {
      "name": "OLDPWD",
      "value": "/"
    },
    {
      "name": "ORIGINAL_XDG_CURRENT_DESKTOP",
      "value": "undefined"
    },
    {
      "name": "P9K_SSH",
      "value": "0"
    },
    {
      "name": "PATH",
      "value": "/Users/mateuszp/.local/share/zinit/polaris/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Library/Apple/usr/bin:/Users/mateuszp/.local/bin"
    },
    {
      "name": "PMSPEC",
      "value": "0uUpiPsf"
    },
    {
      "name": "PWD",
      "value": "/"
    },
    {
      "name": "SHELL",
      "value": "/bin/zsh"
    },
    {
      "name": "SHLVL",
      "value": "0"
    },
    {
      "name": "SSH_AUTH_SOCK",
      "value": "/private/tmp/com.apple.launchd.MpSRriqPRl/Listeners"
    },
    {
      "name": "TMPDIR",
      "value": "/var/folders/zy/qjprwwxn50q2qd0dfkm2kqdc0000gq/T/"
    },
    {
      "name": "USER",
      "value": "mateuszp"
    },
    {
      "name": "VSCODE_CODE_CACHE_PATH",
      "value": "/Users/mateuszp/Library/Application Support/Code/CachedData/f220831ea2d946c0dcb0f3eaa480eb435a2c1260"
    },
    {
      "name": "VSCODE_CRASH_REPORTER_PROCESS_TYPE",
      "value": "extensionHost"
    },
    {
      "name": "VSCODE_CWD",
      "value": "/"
    },
    {
      "name": "VSCODE_ESM_ENTRYPOINT",
      "value": "vs/workbench/api/node/extensionHostProcess"
    },
    {
      "name": "VSCODE_HANDLES_UNCAUGHT_ERRORS",
      "value": "true"
    },
    {
      "name": "VSCODE_IPC_HOOK",
      "value": "/Users/mateuszp/Library/Application Support/Code/1.10-main.sock"
    },
    {
      "name": "VSCODE_NLS_CONFIG",
      "value": "{\"userLocale\":\"en-gb\",\"osLocale\":\"en-au\",\"resolvedLanguage\":\"en\",\"defaultMessagesFile\":\"/Applications/Visual Studio Code.app/Contents/Resources/app/out/nls.messages.json\",\"locale\":\"en-gb\",\"availableLanguages\":{}}"
    },
    {
      "name": "VSCODE_PID",
      "value": "15447"
    },
    {
      "name": "XPC_FLAGS",
      "value": "0x0"
    },
    {
      "name": "XPC_SERVICE_NAME",
      "value": "application.com.microsoft.VSCode.170490890.170490896"
    },
    {
      "name": "ZPFX",
      "value": "/Users/mateuszp/.local/share/zinit/polaris"
    },
    {
      "name": "ZSH_CACHE_DIR",
      "value": "/Users/mateuszp/.cache/zinit"
    },
    {
      "name": "_",
      "value": "/Applications/Visual Studio Code.app/Contents/MacOS/Electron"
    },
    {
      "name": "__CFBundleIdentifier",
      "value": "com.microsoft.VSCode"
    },
    {
      "name": "__CF_USER_TEXT_ENCODING",
      "value": "0x1F7:0x0:0xF"
    },
    {
      "name": "ELECTRON_RUN_AS_NODE",
      "value": "1"
    }
  ],
  "initCommands": [
    "settings set symbols.load-on-demand true"
  ],
  "debugAdapterHostname": "127.0.0.1",
  "debugAdapterPort": 56711
}
2025-09-23 16:59:03.808 [info] Creating debug adapter for session "Debug MyApp"
2025-09-23 16:59:03.808 [info] Session "Debug MyApp" debug configuration:
{
  "type": "lldb-dap",
  "name": "Debug MyApp",
  "request": "launch",
  "cwd": "/Users/mateuszp/Developer/sw/MyApp/build/MyApp.app/Contents/MacOS",
  "MIMode": "lldb",
  "miDebuggerPath": "/usr/bin/lldb",
  "program": "/Users/mateuszp/Developer/sw/MyApp/build/MyApp.app/Contents/MacOS/MyApp",
  "environment": [
    {
      "name": "COMMAND_MODE",
      "value": "unix2003"
    },
    {
      "name": "HOME",
      "value": "/Users/mateuszp"
    },
    {
      "name": "HOMEBREW_CELLAR",
      "value": "/opt/homebrew/Cellar"
    },
    {
      "name": "HOMEBREW_PREFIX",
      "value": "/opt/homebrew"
    },
    {
      "name": "HOMEBREW_REPOSITORY",
      "value": "/opt/homebrew"
    },
    {
      "name": "INFOPATH",
      "value": "/opt/homebrew/share/info:"
    },
    {
      "name": "LOGNAME",
      "value": "mateuszp"
    },
    {
      "name": "MallocNanoZone",
      "value": "0"
    },
    {
      "name": "OLDPWD",
      "value": "/"
    },
    {
      "name": "ORIGINAL_XDG_CURRENT_DESKTOP",
      "value": "undefined"
    },
    {
      "name": "P9K_SSH",
      "value": "0"
    },
    {
      "name": "PATH",
      "value": "/Users/mateuszp/.local/share/zinit/polaris/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Library/Apple/usr/bin:/Users/mateuszp/.local/bin"
    },
    {
      "name": "PMSPEC",
      "value": "0uUpiPsf"
    },
    {
      "name": "PWD",
      "value": "/"
    },
    {
      "name": "PYTHONPATH",
      "value": "/Users/mateuszp/BlackmagicTools/python/"
    },
    {
      "name": "SHELL",
      "value": "/bin/zsh"
    },
    {
      "name": "SHLVL",
      "value": "0"
    },
    {
      "name": "SSH_AUTH_SOCK",
      "value": "/private/tmp/com.apple.launchd.MpSRriqPRl/Listeners"
    },
    {
      "name": "TMPDIR",
      "value": "/var/folders/zy/qjprwwxn50q2qd0dfkm2kqdc0000gq/T/"
    },
    {
      "name": "USER",
      "value": "mateuszp"
    },
    {
      "name": "VSCODE_CODE_CACHE_PATH",
      "value": "/Users/mateuszp/Library/Application Support/Code/CachedData/f220831ea2d946c0dcb0f3eaa480eb435a2c1260"
    },
    {
      "name": "VSCODE_CRASH_REPORTER_PROCESS_TYPE",
      "value": "extensionHost"
    },
    {
      "name": "VSCODE_CWD",
      "value": "/"
    },
    {
      "name": "VSCODE_ESM_ENTRYPOINT",
      "value": "vs/workbench/api/node/extensionHostProcess"
    },
    {
      "name": "VSCODE_HANDLES_UNCAUGHT_ERRORS",
      "value": "true"
    },
    {
      "name": "VSCODE_IPC_HOOK",
      "value": "/Users/mateuszp/Library/Application Support/Code/1.10-main.sock"
    },
    {
      "name": "VSCODE_NLS_CONFIG",
      "value": "{\"userLocale\":\"en-gb\",\"osLocale\":\"en-au\",\"resolvedLanguage\":\"en\",\"defaultMessagesFile\":\"/Applications/Visual Studio Code.app/Contents/Resources/app/out/nls.messages.json\",\"locale\":\"en-gb\",\"availableLanguages\":{}}"
    },
    {
      "name": "VSCODE_PID",
      "value": "15447"
    },
    {
      "name": "XPC_FLAGS",
      "value": "0x0"
    },
    {
      "name": "XPC_SERVICE_NAME",
      "value": "application.com.microsoft.VSCode.170490890.170490896"
    },
    {
      "name": "ZPFX",
      "value": "/Users/mateuszp/.local/share/zinit/polaris"
    },
    {
      "name": "ZSH_CACHE_DIR",
      "value": "/Users/mateuszp/.cache/zinit"
    },
    {
      "name": "_",
      "value": "/Applications/Visual Studio Code.app/Contents/MacOS/Electron"
    },
    {
      "name": "__CFBundleIdentifier",
      "value": "com.microsoft.VSCode"
    },
    {
      "name": "__CF_USER_TEXT_ENCODING",
      "value": "0x1F7:0x0:0xF"
    },
    {
      "name": "ELECTRON_RUN_AS_NODE",
      "value": "1"
    }
  ],
  "initCommands": [
    "settings set symbols.load-on-demand true"
  ],
  "debugAdapterHostname": "127.0.0.1",
  "debugAdapterPort": 56711
}
2025-09-23 16:59:03.808 [info] Spawning debug adapter server on port 56711
2025-09-23 16:59:03.808 [info] Starting debug session "Debug MyApp"
2025-09-23 16:59:16.290 [info] Session "Debug MyApp" exited with code 9

[mateusz-plociennik]

The issue is also reproducible with the latest lldb-dap:

> brew install llvm --HEAD
(...)
> /opt/homebrew/opt/llvm/bin/lldb-dap --version
lldb-dap: Homebrew LLVM version 22.0.0git
  Optimized build.
liblldb: lldb version 22.0.0git (https://github.com/llvm/llvm-project.git revision 0d22f8344aca5e38e2767539c6277f84550ec5c4)
  clang revision 0d22f8344aca5e38e2767539c6277f84550ec5c4
  llvm revision 0d22f8344aca5e38e2767539c6277f84550ec5c4