Desktop reads the login-shell environment once
Desktop 一次性读取登录 shell 环境
macOS Dock, Finder, and Linux desktop launches start Desktop with only the session manager's environment. Variables that users export from `~/.zprofile` or `~/.zshrc`, including PATH entries for Homebrew, version managers, and API keys, are absent from the Host, agent shells, terminals, and profile configuration. The same Host launched from a terminal sees them.
English
Problem
macOS Dock, Finder, and Linux desktop launches start Desktop with only the session manager's environment. Variables that users export from ~/.zprofile or ~/.zshrc, including PATH entries for Homebrew, version managers, and API keys, are absent from the Host, agent shells, terminals, and profile configuration. The same Host launched from a terminal sees them.
Decision
Before creating the first Host, Desktop runs one delimited env -0 dump through <shell> -ilc, where <shell> is the account record's login shell, followed by /bin/zsh, /bin/bash, and /bin/sh. Every Host in the application process uses the merged result. Shell values replace inherited values except probe-session variables and the DSH_* and ELECTRON_* namespaces. The read completes at the closing delimiter. A timeout or quit kills the probe's process group, and a failed read falls back to the inherited environment without blocking startup. Windows skips the read.
Alternatives considered
Read $SHELL instead of the account record. A Dock launch inherits $SHELL from launchd, not from the user's current choice, and a terminal launch can carry a temporary shell. The account record names the shell the user selected with chsh.
Non-interactive -lc only. Most users export PATH additions from ~/.zshrc, which only interactive shells read. Interactive mode requires the probe variables that stop oh-my-zsh update prompts and tmux autostart from blocking.
Let shell values replace DSH_* variables. Desktop resolves DSH_HOME and its profile paths before the read, so a DSH_HOME exported from ~/.zshrc would give the Host a different home from the one Desktop prepared.
Wait for stdout to close. Background processes that startup files start inherit stdout and can hold it open indefinitely, which turns every read into a timeout.
Consequences
Dock and Finder launches give the Host the environment a terminal launch provides. Changes to startup files apply only after Desktop restarts. Startup waits for the read, up to DSH_DESKTOP_LOGIN_SHELL_TIMEOUT_MS per candidate. Account shells that cannot run the POSIX dump, such as csh, tcsh, and nushell, receive the first system shell's environment instead. DSH_* settings must come from the launcher's environment rather than startup files. Unit tests run stand-in shells for the early completion, timeout, abort, and fallback paths, and the Desktop startup test verifies that the Host waits for the read.
中文
问题
从 macOS 的 Dock、Finder 或 Linux 桌面启动 Desktop 时，它只获得会话管理器提供的环境。用户在 ~/.zprofile 或 ~/.zshrc 中导出的变量，包括 Homebrew、版本管理器的 PATH 条目和 API key，在 Host、agent shell、终端和 profile 配置中都不存在。从终端启动同一个 Host 时这些变量都在。
决策
创建第一个 Host 之前，Desktop 通过 <shell> -ilc 运行一次带定界符的 env -0 输出，<shell> 依次为账户记录中的登录 shell、/bin/zsh、/bin/bash 和 /bin/sh。同一应用进程中的所有 Host 使用合并后的结果。shell 的值覆盖继承的值，但读取进程自身的会话变量以及 DSH_* 和 ELECTRON_* 命名空间除外。读取在结束定界符出现时完成。超时或退出会结束读取进程组；读取失败时回退到继承的环境，不阻止启动。Windows 跳过读取。
考虑过的替代方案
读取 $SHELL 而不是账户记录。 从 Dock 启动时，$SHELL 继承自 launchd，而不是用户当前的选择；从终端启动时它可能是临时 shell。账户记录给出用户用 chsh 选择的 shell。
只使用非交互的 -lc。 多数用户在 ~/.zshrc 中添加 PATH，而只有交互式 shell 会读取它。交互模式需要设置读取变量，避免 oh-my-zsh 更新提示和 tmux 自动启动阻塞。
允许 shell 的值覆盖 DSH_* 变量。 Desktop 在读取之前已解析 DSH_HOME 及其 profile 路径，因此 ~/.zshrc 导出的 DSH_HOME 会让 Host 使用与 Desktop 已准备的不同的 home。
等待 stdout 关闭。 启动文件启动的后台进程继承 stdout，可能无限期保持它打开，使每次读取都超时。
影响
从 Dock 和 Finder 启动时，Host 获得与从终端启动相同的环境。修改启动文件后需要重启 Desktop 才生效。启动需要等待读取，每个候选最多 DSH_DESKTOP_LOGIN_SHELL_TIMEOUT_MS。无法运行 POSIX 输出命令的账户 shell（如 csh、tcsh 和 nushell）改为获得第一个系统 shell 的环境。DSH_* 设置必须来自启动方的环境，而不是启动文件。单元测试用替身 shell 覆盖提前完成、超时、中止和回退路径，Desktop 启动测试验证 Host 等待读取完成。