fix(virtualenvwrapper): several changes for checking git directory, including fixes (#5663)

* Test only for the presence of a .git directory in virtualenvwrapper

Instead of using both $(git rev-parse --show-toplevel) and a check for
a .git directory, use just the latter. As well as being redundant
the former does not work quite so well when using multiple worktrees;
each worktree will be treated as a separate project.

* Unset ENV_NAME & deactivate if no virtualenv found

This addresses #4603 without breaking current behaviour (where current
behaviour is correct).

When changing directories, if there is no environment matching
ENV_NAME, ENV_NAME is emptied and deactivate called if there is a
current environment active (based on CD_VIRTUAL_ENV).

* Use path comparison not string comparison for paths

This will solve part of issue #4255 where WORKON_HOME is defined with a
trailing slash or not normalised in some way, as well as instances
where symlinks are used, and any other instances where constructed
paths don't exactly match even though they go to the same file.

Co-authored-by: Robby Russell <robby@planetargon.com>

plugins/virtualenvwrapper/virtualenvwrapper.plugin.zsh

@@ -35,27 +35,19 @@ if [[ ! $DISABLE_VENV_CD -eq 1 ]]; then
   function workon_cwd {
     if [[ -z "$WORKON_CWD" ]]; then
       local WORKON_CWD=1
-      # Check if this is a Git repo
-      local GIT_REPO_ROOT=""
-      local GIT_TOPLEVEL="$(git rev-parse --show-toplevel 2> /dev/null)"
-      if [[ $? == 0 ]]; then
-        GIT_REPO_ROOT="$GIT_TOPLEVEL"
-      fi
       # Get absolute path, resolving symlinks
       local PROJECT_ROOT="${PWD:A}"
       while [[ "$PROJECT_ROOT" != "/" && ! -e "$PROJECT_ROOT/.venv" \
-               && ! -d "$PROJECT_ROOT/.git"  && "$PROJECT_ROOT" != "$GIT_REPO_ROOT" ]]; do
+          && ! -d "$PROJECT_ROOT/.git" ]]; do
         PROJECT_ROOT="${PROJECT_ROOT:h}"
       done
-      if [[ "$PROJECT_ROOT" == "/" ]]; then
-        PROJECT_ROOT="."
-      fi
+
       # Check for virtualenv name override
       if [[ -f "$PROJECT_ROOT/.venv" ]]; then
         ENV_NAME="$(cat "$PROJECT_ROOT/.venv")"
       elif [[ -f "$PROJECT_ROOT/.venv/bin/activate" ]];then
         ENV_NAME="$PROJECT_ROOT/.venv"
-      elif [[ "$PROJECT_ROOT" != "." ]]; then
+      elif [[ "$PROJECT_ROOT" != "/" ]]; then
         ENV_NAME="${PROJECT_ROOT:t}"
       else
         ENV_NAME=""
@@ -68,14 +60,21 @@ if [[ ! $DISABLE_VENV_CD -eq 1 ]]; then
       fi
       if [[ "$ENV_NAME" != "" ]]; then
         # Activate the environment only if it is not already active
-        if [[ "$VIRTUAL_ENV" != "$WORKON_HOME/$ENV_NAME" ]]; then
+        if [[ ! "$VIRTUAL_ENV" -ef "$WORKON_HOME/$ENV_NAME" ]]; then
           if [[ -e "$WORKON_HOME/$ENV_NAME/bin/activate" ]]; then
             workon "$ENV_NAME" && export CD_VIRTUAL_ENV="$ENV_NAME"
           elif [[ -e "$ENV_NAME/bin/activate" ]]; then
             source $ENV_NAME/bin/activate && export CD_VIRTUAL_ENV="$ENV_NAME"
+          else
+            ENV_NAME=""
           fi
         fi
       fi
+      if [[ "$ENV_NAME" == "" && -n $CD_VIRTUAL_ENV && -n $VIRTUAL_ENV ]]; then
+        # We've just left the repo, deactivate the environment
+        # Note: this only happens if the virtualenv was activated automatically
+        deactivate && unset CD_VIRTUAL_ENV
+      fi
     fi
   }