Drastically speed up precommand hook by caching active version to skip redundant activate calls (#523)

bin/pyenv-virtualenv-init

@@ -9,6 +9,23 @@
 set -e
 [ -n "$PYENV_DEBUG" ] && set -x
 
+# Detect stat format for mtime: GNU uses -c %Y, BSD uses -f %m
+# -L follows symlinks: a symlinked .python-version reflects target changes
+if stat -L -c %Y / >/dev/null 2>&1; then
+  _stat_fmt="-L -c %Y"
+else
+  _stat_fmt="-L -f %m"
+fi
+
+# Check for version-name hooks at init time. Hooks can alter version
+# resolution in ways the mtime cache cannot track. If present, the hook
+# falls back to upstream behavior (no caching). Restart shell after
+# installing or removing pyenv plugins.
+_has_version_hooks=""
+if [ -n "$(pyenv hooks version-name 2>/dev/null)" ]; then
+  _has_version_hooks=1
+fi
+
 resolve_link() {
   $(type -p greadlink readlink | head -1) "$1"
 }
@@ -103,7 +120,8 @@ esac
 
 case "$shell" in
 fish )
-  cat <<EOS
+  if [ -n "$_has_version_hooks" ]; then
+    cat <<EOS
 function _pyenv_virtualenv_hook --on-event fish_prompt;
   set -l ret \$status
   if [ -n "\$VIRTUAL_ENV" ]
@@ -114,6 +132,53 @@ function _pyenv_virtualenv_hook --on-event fish_prompt;
   return \$ret
 end
 EOS
+  else
+    cat <<EOS
+function _pyenv_virtualenv_hook --on-event fish_prompt;
+  set -l ret \$status
+  if test "\$PYENV_VERSION" = "\$_PYENV_VH_VERSION" \\
+    -a "\$VIRTUAL_ENV" = "\$_PYENV_VH_VENV"
+    if test -n "\$PYENV_VERSION"
+      return \$ret
+    end
+    if test "\$PWD" = "\$_PYENV_VH_PWD" \\
+      -a "(stat ${_stat_fmt} \$_PYENV_VH_PATHS 2>/dev/null)" = "\$_PYENV_VH_MTIMES"
+      return \$ret
+    end
+  end
+  if [ -n "\$VIRTUAL_ENV" ]
+    pyenv activate --quiet; or pyenv deactivate --quiet; or true
+  else
+    pyenv activate --quiet; or true
+  end
+  set -g _PYENV_VH_PWD "\$PWD"
+  set -g _PYENV_VH_VERSION "\$PYENV_VERSION"
+  set -g _PYENV_VH_VENV "\$VIRTUAL_ENV"
+  set -l d "\$PWD"
+  set -l _pvh_found_local 0
+  set -g _PYENV_VH_PATHS
+  while true
+    if test -f "\$d/.python-version"; or test -L "\$d/.python-version"
+      set -g _PYENV_VH_PATHS \$_PYENV_VH_PATHS "\$d/.python-version"
+      if test -f "\$d/.python-version" 
+        set _pvh_found_local 1
+        break
+      end
+    else
+      set -g _PYENV_VH_PATHS \$_PYENV_VH_PATHS "\$d"
+    end
+    test "\$d" = "/"; and break
+    set d (string replace -r '/[^/]*\$' '' -- "\$d")
+    test -z "\$d"; and set d "/"
+  end
+  if test "\$_pvh_found_local" = "0"
+    set -g _PYENV_VH_PATHS \$_PYENV_VH_PATHS "\$PYENV_ROOT/version"
+  end
+  set -g _PYENV_VH_MTIMES (stat ${_stat_fmt} \$_PYENV_VH_PATHS 2>/dev/null)
+  return \$ret
+end
+EOS
+  fi
  ;;
 ksh )
   cat <<EOS
@@ -128,7 +193,8 @@ EOS
 esac
 
 if [[ "$shell" != "fish" ]]; then
-  cat <<EOS
+  if [ -n "$_has_version_hooks" ]; then
+    cat <<EOS
   local ret=\$?
   if [ -n "\${VIRTUAL_ENV-}" ]; then
     eval "\$(pyenv sh-activate --quiet || pyenv sh-deactivate --quiet || true)" || true
@@ -138,6 +204,52 @@ if [[ "$shell" != "fish" ]]; then
   return \$ret
 };
 EOS
+  else
+    cat <<EOS
+  local ret=\$?
+  # Cache: env vars checked once, path list and stat rebuilt on miss only
+  if [ "\${PYENV_VERSION-}" = "\${_PYENV_VH_VERSION-}" ] \\
+    && [ "\${VIRTUAL_ENV-}" = "\${_PYENV_VH_VENV-}" ]; then
+    if [ -n "\${PYENV_VERSION-}" ]; then
+      return \$ret
+    fi
+    if [ "\${PWD}" = "\${_PYENV_VH_PWD-}" ] \\
+      && [ "\$(stat ${_stat_fmt} "\${_PYENV_VH_PATHS[@]}" 2>/dev/null)" = "\${_PYENV_VH_MTIMES-}" ]; then
+      return \$ret
+    fi
+  fi
+  if [ -n "\${VIRTUAL_ENV-}" ]; then
+    eval "\$(pyenv sh-activate --quiet || pyenv sh-deactivate --quiet || true)" || true
+  else
+    eval "\$(pyenv sh-activate --quiet || true)" || true
+  fi
+  _PYENV_VH_PWD="\${PWD}"
+  _PYENV_VH_VERSION="\${PYENV_VERSION-}"
+  _PYENV_VH_VENV="\${VIRTUAL_ENV-}"
+  local _pvh_d="\${PWD}" _pvh_found_local=0
+  _PYENV_VH_PATHS=()
+  while :; do
+    if [ -f "\${_pvh_d}/.python-version" ] || [ -L "\${_pvh_d}/.python-version" ]; then
+      _PYENV_VH_PATHS+=("\${_pvh_d}/.python-version")
+      if [ -f "\${_pvh_d}/.python-version" ]; then 
+        _pvh_found_local=1
+        break
+      fi
+    else
+      _PYENV_VH_PATHS+=("\${_pvh_d}")
+    fi
+    [ "\${_pvh_d}" = "/" ] && break
+    _pvh_d="\${_pvh_d%/*}"
+    [ -z "\${_pvh_d}" ] && _pvh_d="/"
+  done
+  if [ "\${_pvh_found_local}" = "0" ]; then
+    _PYENV_VH_PATHS+=("\${PYENV_ROOT}/version")
+  fi
+  _PYENV_VH_MTIMES="\$(stat ${_stat_fmt} "\${_PYENV_VH_PATHS[@]}" 2>/dev/null)"
+  return \$ret
+};
+EOS
+  fi
 
   case "$shell" in
   bash )

test/init.bats

@@ -54,11 +54,45 @@ export PATH="${TMP}/pyenv/plugins/pyenv-virtualenv/shims:\${PATH}";
 export PYENV_VIRTUALENV_INIT=1;
 _pyenv_virtualenv_hook() {
   local ret=\$?
+  # Cache: env vars checked once, path list and stat rebuilt on miss only
+  if [ "\${PYENV_VERSION-}" = "\${_PYENV_VH_VERSION-}" ] \\
+    && [ "\${VIRTUAL_ENV-}" = "\${_PYENV_VH_VENV-}" ]; then
+    if [ -n "\${PYENV_VERSION-}" ]; then
+      return \$ret
+    fi
+    if [ "\${PWD}" = "\${_PYENV_VH_PWD-}" ] \\
+      && [ "\$(stat ${_stat_fmt} "\${_PYENV_VH_PATHS[@]}" 2>/dev/null)" = "\${_PYENV_VH_MTIMES-}" ]; then
+      return \$ret
+    fi
+  fi
   if [ -n "\${VIRTUAL_ENV-}" ]; then
     eval "\$(pyenv sh-activate --quiet || pyenv sh-deactivate --quiet || true)" || true
   else
     eval "\$(pyenv sh-activate --quiet || true)" || true
   fi
+  _PYENV_VH_PWD="\${PWD}"
+  _PYENV_VH_VERSION="\${PYENV_VERSION-}"
+  _PYENV_VH_VENV="\${VIRTUAL_ENV-}"
+  local _pvh_d="\${PWD}" _pvh_found_local=0
+  _PYENV_VH_PATHS=()
+  while :; do
+    if [ -f "\${_pvh_d}/.python-version" ] || [ -L "\${_pvh_d}/.python-version" ]; then
+      _PYENV_VH_PATHS+=("\${_pvh_d}/.python-version")
+      if [ -f "\${_pvh_d}/.python-version" ]; then 
+        _pvh_found_local=1
+        break
+      fi
+    else
+      _PYENV_VH_PATHS+=("\${_pvh_d}")
+    fi
+    [ "\${_pvh_d}" = "/" ] && break
+    _pvh_d="\${_pvh_d%/*}"
+    [ -z "\${_pvh_d}" ] && _pvh_d="/"
+  done
+  if [ "\${_pvh_found_local}" = "0" ]; then
+    _PYENV_VH_PATHS+=("\${PYENV_ROOT}/version")
+  fi
+  _PYENV_VH_MTIMES="\$(stat ${_stat_fmt} "\${_PYENV_VH_PATHS[@]}" 2>/dev/null)"
   return \$ret
 };
 if ! [[ "\${PROMPT_COMMAND-}" =~ _pyenv_virtualenv_hook ]]; then
@@ -78,11 +112,45 @@ set -gx PATH '${TMP}/pyenv/plugins/pyenv-virtualenv/shims' \$PATH;
 set -gx PYENV_VIRTUALENV_INIT 1;
 function _pyenv_virtualenv_hook --on-event fish_prompt;
   set -l ret \$status
+  if test "\$PYENV_VERSION" = "\$_PYENV_VH_VERSION" \\
+    -a "\$VIRTUAL_ENV" = "\$_PYENV_VH_VENV"
+    if test -n "\$PYENV_VERSION"
+      return \$ret
+    end
+    if test "\$PWD" = "\$_PYENV_VH_PWD" \\
+      -a "(stat ${_stat_fmt} \$_PYENV_VH_PATHS 2>/dev/null)" = "\$_PYENV_VH_MTIMES"
+      return \$ret
+    end
+  end
   if [ -n "\$VIRTUAL_ENV" ]
     pyenv activate --quiet; or pyenv deactivate --quiet; or true
   else
     pyenv activate --quiet; or true
   end
+  set -g _PYENV_VH_PWD "\$PWD"
+  set -g _PYENV_VH_VERSION "\$PYENV_VERSION"
+  set -g _PYENV_VH_VENV "\$VIRTUAL_ENV"
+  set -l d "\$PWD"
+  set -l _pvh_found_local 0
+  set -g _PYENV_VH_PATHS
+  while true
+    if test -f "\$d/.python-version"; or test -L "\$d/.python-version"
+      set -g _PYENV_VH_PATHS \$_PYENV_VH_PATHS "\$d/.python-version"
+      if test -f "\$d/.python-version" 
+        set _pvh_found_local 1
+        break
+      end
+    else
+      set -g _PYENV_VH_PATHS \$_PYENV_VH_PATHS "\$d"
+    end
+    test "\$d" = "/"; and break
+    set d (string replace -r '/[^/]*\$' '' -- "\$d")
+    test -z "\$d"; and set d "/"
+  end
+  if test "\$_pvh_found_local" = "0"
+    set -g _PYENV_VH_PATHS \$_PYENV_VH_PATHS "\$PYENV_ROOT/version"
+  end
+  set -g _PYENV_VH_MTIMES (stat ${_stat_fmt} \$_PYENV_VH_PATHS 2>/dev/null)
   return \$ret
 end
 EOS
@@ -97,11 +165,45 @@ export PATH="${TMP}/pyenv/plugins/pyenv-virtualenv/shims:\${PATH}";
 export PYENV_VIRTUALENV_INIT=1;
 _pyenv_virtualenv_hook() {
   local ret=\$?
+  # Cache: env vars checked once, path list and stat rebuilt on miss only
+  if [ "\${PYENV_VERSION-}" = "\${_PYENV_VH_VERSION-}" ] \\
+    && [ "\${VIRTUAL_ENV-}" = "\${_PYENV_VH_VENV-}" ]; then
+    if [ -n "\${PYENV_VERSION-}" ]; then
+      return \$ret
+    fi
+    if [ "\${PWD}" = "\${_PYENV_VH_PWD-}" ] \\
+      && [ "\$(stat ${_stat_fmt} "\${_PYENV_VH_PATHS[@]}" 2>/dev/null)" = "\${_PYENV_VH_MTIMES-}" ]; then
+      return \$ret
+    fi
+  fi
   if [ -n "\${VIRTUAL_ENV-}" ]; then
     eval "\$(pyenv sh-activate --quiet || pyenv sh-deactivate --quiet || true)" || true
   else
     eval "\$(pyenv sh-activate --quiet || true)" || true
   fi
+  _PYENV_VH_PWD="\${PWD}"
+  _PYENV_VH_VERSION="\${PYENV_VERSION-}"
+  _PYENV_VH_VENV="\${VIRTUAL_ENV-}"
+  local _pvh_d="\${PWD}" _pvh_found_local=0
+  _PYENV_VH_PATHS=()
+  while :; do
+    if [ -f "\${_pvh_d}/.python-version" ] || [ -L "\${_pvh_d}/.python-version" ]; then
+      _PYENV_VH_PATHS+=("\${_pvh_d}/.python-version")
+      if [ -f "\${_pvh_d}/.python-version" ]; then 
+        _pvh_found_local=1
+        break
+      fi
+    else
+      _PYENV_VH_PATHS+=("\${_pvh_d}")
+    fi
+    [ "\${_pvh_d}" = "/" ] && break
+    _pvh_d="\${_pvh_d%/*}"
+    [ -z "\${_pvh_d}" ] && _pvh_d="/"
+  done
+  if [ "\${_pvh_found_local}" = "0" ]; then
+    _PYENV_VH_PATHS+=("\${PYENV_ROOT}/version")
+  fi
+  _PYENV_VH_MTIMES="\$(stat ${_stat_fmt} "\${_PYENV_VH_PATHS[@]}" 2>/dev/null)"
   return \$ret
 };
 typeset -g -a precmd_functions

test/test_helper.bash

@@ -1,4 +1,12 @@
 export TMP="$BATS_TEST_DIRNAME/tmp"
+
+# Detect stat format for mtime: GNU uses -c %Y, BSD uses -f %m
+# Must match the detection in bin/pyenv-virtualenv-init
+if stat -L -c %Y / >/dev/null 2>&1; then
+  _stat_fmt="-L -c %Y"
+else
+  _stat_fmt="-L -f %m"
+fi
 export PS4='+(${BASH_SOURCE}:${LINENO}): ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
 
 PATH=/usr/bin:/usr/sbin:/bin:/sbin