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>
perf(init): cache the LocalHostName lookup instead of inferring it
2026-09-28 05:56:07 +02:00 · 2026-09-07 08:25:24 -07:00 · 2026-09-07 08:07:51 -07:00 · 2026-09-06 08:03:54 -07:00
2 changed files with 24 additions and 15 deletions
@@ -146,23 +146,16 @@ esac
 # the host name to disambiguate local vs. remote paths.
 function omz_termsupport_cwd {
  setopt localoptions unset
-  # Percent-encode the host and path names. Encoding forks a subshell each,
-  # so keep the result and only redo it when $HOST or $PWD changed.
-  local cache_key="$HOST:$PWD:${KONSOLE_PROFILE_NAME:+1}:${KONSOLE_DBUS_SESSION:+1}"
-  if [[ "$_omz_termsupport_cwd_key" != "$cache_key" ]]; then
-    local URL_HOST URL_PATH
-    URL_HOST="$(omz_urlencode -P "$HOST")" || return 1
-    URL_PATH="$(omz_urlencode -P "$PWD")" || return 1
+  # Percent-encode the host and path names.
+  local URL_HOST URL_PATH
+  URL_HOST="$(omz_urlencode -P $HOST)" || return 1
+  URL_PATH="$(omz_urlencode -P $PWD)" || return 1

-    # Konsole errors if the HOST is provided
-    [[ -z "$KONSOLE_PROFILE_NAME" && -z "$KONSOLE_DBUS_SESSION"  ]] || URL_HOST=""
-
-    typeset -g _omz_termsupport_cwd_key="$cache_key"
-    typeset -g _omz_termsupport_cwd_url="file://${URL_HOST}${URL_PATH}"
-  fi
+  # Konsole errors if the HOST is provided
+  [[ -z "$KONSOLE_PROFILE_NAME" && -z "$KONSOLE_DBUS_SESSION"  ]] || URL_HOST=""

  # common control sequence (OSC 7) to set current host and path
-  printf "\e]7;%s\e\\" "$_omz_termsupport_cwd_url"
+  printf "\e]7;file://%s%s\e\\" "${URL_HOST}" "${URL_PATH}"
 }

 # Use a precmd hook instead of a chpwd hook to avoid contaminating output
@@ -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