无OhMyZsh环境下zsh的Git相关功能响应缓慢问题排查

问题描述 #

• 仅在Git目录中，提示符加载缓慢；
• Tab自动补全变慢，例如执行git checkout some-bra[tab]耗时远超以往。

推测原因 #

此前使用git switch拉取过一个未合并的远程分支，虽已删除本地分支，但所有Git仓库内zsh仍卡顿，推测zsh在构建提示符或处理自动补全时会检查远程Git内容。

用户配置信息 #

~/.zshrc相关配置片段 #

__git_files () {
    _wanted files expl 'local files' _files
}

autoload -Uz vcs_info
precmd() { vcs_info }

zstyle ':vcs_info:git:*' formats '(%b)'
zstyle ':vcs_info:*' enable git

zstyle ':vcs_info:*' check-for-changes true
zstyle ':vcs_info:*' unstagedstr ' *'
zstyle ':vcs_info:*' stagedstr ' +'
zstyle ':vcs_info:git:*' formats       '(%b%u%c)'
zstyle ':vcs_info:git:*' actionformats '(%b|%a%u%c)'

function git_branch_name() {
  branch=$(git symbolic-ref HEAD 2> /dev/null | awk 'BEGIN{FS="/"} {print $NF}')
  if [[ $branch == "" ]]; 
  then
    :
  else
    echo '- ('$branch')'
  fi
}

setopt prompt_subst
PROMPT=$'
%F{white}\u256d %~ ${vcs_info_msg_0_}
\u2570 %# %f'

setopt auto_cd

autoload -U compinit; compinit
# zstyle ':completion:*' matcher-list 'm:{a-z}={A-Za-z}'

# 0 -- vanilla completion (abc => abc)
# 1 -- smart case completion (abc => Abc)
# 2 -- word flex completion (abc => A-big-Car)
# 3 -- full flex completion (abc => ABraCadabra)
zstyle ':completion:*' matcher-list '' \
  'm:{a-z\-}={A-Z\_}' \
  'r:[^[:alpha:]]||[[:alpha:]]=** r:|=* m:{a-z\-}={A-Z\_}' \
  'r:|?=** m:{a-z\-}={A-Z\_}'

~/.zshrc完整配置 #

if [[ "$ZPROF" = true ]]; then
  zmodload zsh/zprof
fi

# printf '\n%.0s' {1..100}

# If you come from bash you might have to change your $PATH.
# export PATH=$HOME/bin:/usr/local/bin:$PATH
export PATH=$PATH:$HOME/custom-git-commands/

export MANPAGER="vim -M +MANPAGER -c 'syntax off' -c 'set foldlevel=9999' -c 'set number relativenumber' -\"

plugins=(git wd zshmarks)

export ZSH_COMPDUMP=$ZSH/cache/.zcompdump-$HOST

# User configuration

# Compilation flags
# export ARCHFLAGS="-arch x86_64"

# Set personal aliases, overriding those provided by oh-my-zsh libs,
# plugins, and themes. Aliases can be placed here, though oh-my-zsh
# users are encouraged to define aliases within the ZSH_CUSTOM folder.
# For a full list of active aliases, run `alias`.
#
# Example aliases
# alias zshconfig="mate ~/.zshrc"

HISTSIZE=5000
HISTFILE=~/.zsh_history
SAVEHIST=5000
HISTDUP=erase
setopt appendhistory
setopt sharehistory
setopt incappendhistory
setopt hist_ignore_all_dups
setopt hist_save_no_dups
setopt hist_ignore_dups
setopt hist_find_no_dups

# uses homebrew-installed GNU coreutils' ls
alias ls='gls --group-directories-first -F -a --color=never'

alias gm="jump"
alias sm="bookmark"
alias dm="deletemark"
alias pm="showmarks"

alias chrome="open -a 'Google Chrome'"
alias copypath="pwd|pbcopy"

alias python="python3"

function chpwd_do_ls () {
    ls
}
chpwd_functions=( chpwd_do_ls )

declare -a SCOLDS
SCOLDS=(
  "Everything is an instruction."
  "Remember the scream test."
    "rm is a dangerous command."
    "Read the error message."
  "Read the docs."
  "Generally, not trying too hard will result in good enough code."
)
alias clear='echo ${SCOLDS[ $RANDOM % ${#SCOLDS[@]} + 1 ]}'
alias c='clear'

alias vimz='vim ~/.zshrc'
alias vimv='vim ~/.vimrc'

alias sc='source ~/.zshrc'
alias ez='exec zsh'

alias ..='cd ..'

alias confgit='/usr/bin/git --git-dir=$HOME/.cfg/ --work-tree=$HOME'

alias ga='git add .'
alias gcm='git commit -m'
alias grao='git remote add origin'
alias gp='git push'
alias gst='git status'
alias gpuo='git push --set-upstream origin'
alias glo='git log --oneline'
alias gvl='git vlog'
alias gvd='git vdiff'
alias grb='git rebase'
alias gcb='git checkout -b'
alias gco='git checkout'

precmd() { print "" }

__git_files () {
    _wanted files expl 'local files' _files
}

autoload -Uz vcs_info
precmd() { vcs_info }

zstyle ':vcs_info:git:*' formats '(%b)'
zstyle ':vcs_info:*' enable git

zstyle ':vcs_info:*' check-for-changes true
zstyle ':vcs_info:*' unstagedstr ' *'
zstyle ':vcs_info:*' stagedstr ' +'
zstyle ':vcs_info:git:*' formats       '(%b%u%c)'
zstyle ':vcs_info:git:*' actionformats '(%b|%a%u%c)'

function git_branch_name() {
  branch=$(git symbolic-ref HEAD 2> /dev/null | awk 'BEGIN{FS="/"} {print $NF}')
  if [[ $branch == "" ]]; 
  then
    :
  else
    echo '- ('$branch')'
  fi
}

setopt prompt_subst
PROMPT=$'
%F{white}\u256d %~ ${vcs_info_msg_0_}
\u2570 %# %f'

setopt auto_cd

autoload -U compinit; compinit
# zstyle ':completion:*' matcher-list 'm:{a-z}={A-Za-z}'

# 0 -- vanilla completion (abc => abc)
# 1 -- smart case completion (abc => Abc)
# 2 -- word flex completion (abc => A-big-Car)
# 3 -- full flex completion (abc => ABraCadabra)
zstyle ':completion:*' matcher-list '' \
  'm:{a-z\-}={A-Z\_}' \
  'r:[^[:alpha:]]||[[:alpha:]]=** r:|=* m:{a-z\-}={A-Z\_}' \
  'r:|?=** m:{a-z\-}={A-Z\_}'

timezsh() {
  shell=${1-$SHELL}
  for i in $(seq 1 10); do /usr/bin/time $shell -i -c exit; done
}
profzsh() {
  shell=${1-$SHELL}
  ZPROF=true $shell -i -c exit
}

if [[ "$ZPROF" = true ]]; then
  zprof
fi

解决方案 #

1. 清理Git远程分支缓存 #

执行以下命令清理本地无效的远程分支引用与Git缓存：

git fetch --prune
git gc --prune=now

2. 优化vcs_info性能 #

关闭check-for-changes以减少提示符渲染时的文件变更检查开销：

zstyle ':vcs_info:*' check-for-changes false

3. 修复precmd重复定义问题 #

合并两次定义的precmd()函数，避免逻辑覆盖：

precmd() {
  print ""
  vcs_info
}

4. 优化Git补全策略 #

限制git分支补全仅考虑本地分支，减少远程查询开销：

zstyle ':completion:*:git-checkout:*' sort false
zstyle ':completion:*:git-checkout:*' tag-order branches tags

5. 重新生成补全缓存 #

执行命令更新zsh补全缓存：

compinit -i

6. 定位性能瓶颈 #

使用配置中的profzsh函数分析zsh执行耗时，确认优化效果：

profzsh

内容的提问来源于stack exchange，提问作者Aaron Parisi