fix(init): bound the LocalHostName cache and don't cache lookup failures

Keying the cache on $HOST alone can't notice a LocalHostName rename
while HostName stays fixed, which would pin a stale identity forever.
Expire the entry after a day, like lib/grep.zsh does, so a rename is
picked up without giving up the fork on almost every start.

Only write the cache when scutil actually answered, so a transient
failure falls back to ${HOST/.*/} for that shell instead of pinning the
fallback name for the next day.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

oh-my-zsh.sh

@@ -100,7 +100,23 @@ done
 # Figure out the SHORT hostname
 if [[ "$OSTYPE" = darwin* ]]; then
   # macOS's $HOST changes with dhcp, etc. Use LocalHostName if possible.
-  SHORT_HOST=$(scutil --get LocalHostName 2>/dev/null) || SHORT_HOST="${HOST/.*/}"
+  # scutil costs a fork on every start, so remember its answer for a day
+  # (like lib/grep.zsh) and re-check sooner if $HOST changes.
+  __omz_host_cache="$ZSH_CACHE_DIR/localhostname"
+  __omz_host_cached=("$__omz_host_cache"(Nm-1))
+  if [[ -n "$__omz_host_cached" ]]; then
+    { read -r __omz_host_key && read -r SHORT_HOST } < "$__omz_host_cache"
+  fi
+  if [[ "$__omz_host_key" != "$HOST" || -z "$SHORT_HOST" ]]; then
+    # only cache what scutil actually answered, so a transient failure
+    # doesn't pin the fallback name for a day
+    if SHORT_HOST=$(scutil --get LocalHostName 2>/dev/null) && [[ -n "$SHORT_HOST" ]]; then
+      [[ ! -w "$ZSH_CACHE_DIR" ]] || print -rl -- "$HOST" "$SHORT_HOST" >| "$__omz_host_cache"
+    else
+      SHORT_HOST="${HOST/.*/}"
+    fi
+  fi
+  unset __omz_host_cache __omz_host_cached __omz_host_key
 else
   SHORT_HOST="${HOST/.*/}"
 fi

plugins/git/git.plugin.zsh

@@ -1,25 +1,6 @@
 # Git version checking
 autoload -Uz is-at-least
-# Running `git version` forks on every startup, so cache the result for a day
-# in $ZSH_CACHE_DIR, keyed on the git command path, mtime, and exec path.
-() {
-  local cache="$ZSH_CACHE_DIR/git-version" key exec_path
-  local -a stat lines
-  zmodload -F zsh/stat b:zstat
-  zstat -A stat +mtime -- "$commands[git]" 2>/dev/null
-  exec_path="$(git --exec-path 2>/dev/null)"
-  key="$commands[git] $stat[1] $exec_path"
-
-  lines=("$cache"(Nm-1))
-  (( $#lines )) && lines=("${(@f)$(<"$cache")}")
-  if [[ "$lines[1]" = "$key" ]]; then
-    git_version="$lines[2]"
-    return
-  fi
-
 git_version="${${(As: :)$(git version 2>/dev/null)}[3]}"
-  [[ ! -w "$ZSH_CACHE_DIR" ]] || print -rl -- "$key" "$git_version" >| "$cache"
-}
 
 #
 # Functions Current