perf(pyenv): initialize shell integration once without rehash

Login shells source the fragment twice to restore shim precedence after the system profile. Reapplying PATH does not require repeating shell integration or rebuilding shims.

tests/installers.sh

@@ -214,6 +214,26 @@ HOME="$pyenv_env_home" XDG_CONFIG_HOME="$pyenv_env_xdg" \
     zsh -lc '[[ "$(command -v python3)" == "$HOME/.pyenv/shims/python3" ]]' ||
     fail "pyenv Python is not restored in login zsh after the system profile"
 
+# Interactive initialization runs once while repeated sourcing restores PATH.
+mkdir -p "$pyenv_env_home/.pyenv/bin"
+cat >"$pyenv_env_home/.pyenv/bin/pyenv" <<'PYENV'
+#!/bin/sh
+printf '%s\n' "$*" >> "$PYENV_ROOT/init-calls"
+printf '%s\n' 'pyenv() { command pyenv "$@"; }'
+PYENV
+chmod +x "$pyenv_env_home/.pyenv/bin/pyenv"
+HOME="$pyenv_env_home" PYENV_ROOT="$pyenv_env_home/.pyenv" PATH=/usr/bin:/bin \
+    zsh -dfic '
+        source "$1"
+        (( $+functions[pyenv] )) || exit 1
+        path=(/usr/bin /bin)
+        source "$1"
+        [[ $(command -v python3) == "$PYENV_ROOT/shims/python3" ]]
+    ' zsh "$ROOT/zsh/pyenv.zsh" ||
+    fail "interactive pyenv initialization did not preserve its function and Python PATH"
+printf '%s\n' 'init - --no-rehash zsh' | cmp -s - "$pyenv_env_home/.pyenv/init-calls" ||
+    fail "pyenv initialization must run once without a startup rehash"
+
 # A later easyzsh migration must not move the login hook before the system profile.
 HOME="$pyenv_env_home" bash "$ROOT/deploy.sh" --home "$pyenv_env_home" --migrate-zprofile >/dev/null
 grep -Fqx "$pyenv_login_hook" "$pyenv_env_home/.zprofile" ||

zsh/pyenv.zsh

@@ -3,6 +3,8 @@ export PYENV_ROOT="${PYENV_ROOT:-$HOME/.pyenv}"
 [[ -d "$PYENV_ROOT/bin" ]] && path=("$PYENV_ROOT/bin" ${path:#$PYENV_ROOT/bin})
 [[ -d "$PYENV_ROOT/shims" ]] && path=("$PYENV_ROOT/shims" ${path:#$PYENV_ROOT/shims})
 export PATH
-if [[ -o interactive ]] && command -v pyenv &> /dev/null; then
+# Login profiles can reapply PATH without repeating shell integration.
-  eval "$(pyenv init - zsh)"
+# Run `pyenv rehash` after installing entry points through `python -m pip`.
+if [[ -o interactive ]] && (( ! $+functions[pyenv] )) && command -v pyenv &> /dev/null; then
+  eval "$(pyenv init - --no-rehash zsh)"
 fi