From f0af465bc83202580f12e585824587c892dcd2b3 Mon Sep 17 00:00:00 2001
From: Peter Heatwole <pfheatwole@gmail.com>
Date: Fri, 29 Jan 2021 11:46:41 -0800
Subject: [PATCH 1/5] Overhaul

* Eliminated the dependency on `column` from `util-linux`

* Added the general framework for adding command line options

* Add a `-r|--raw` option to make scripting easier
---
 README.rst      |  46 +++++++++------
 bin/pyenv-users | 147 +++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 144 insertions(+), 49 deletions(-)

diff --git a/README.rst b/README.rst
index b2b3c24..525dd1c 100644
--- a/README.rst
+++ b/README.rst
@@ -14,11 +14,11 @@ virtual environments, regardless of how they were created (``python -m venv
 Prerequisites
 -------------
 
-Requires ``find`` from GNU ``findutils`` to collect a list of candidates.
+* BASH >= 4.3 (for ``nameref`` parameters)
 
-Uses ``column`` from the ``util-linux`` package (if available) for
-pretty-printing the output. If ``column`` is not available, the output is the
-simple form ``<version>:<venv path>``.
+* GNU coreutils (for ``readlink`` and ``realpath``)
+
+* GNU findutils (for ``find``)
 
 
 Installation
@@ -52,20 +52,34 @@ search your home directory:
    3.8.6          /home/peter/.cache/pypoetry/virtualenvs/my_project-KM_3YcvM-py3.8
    pypy3.6-7.3.1  /home/peter/work/venvs/example1
 
+For scripting, use the ``--raw`` option to output a list of ``:`` separated
+items:
 
-Disclaimer
-----------
+.. code-block:: bash
+
+   $ pyenv users --raw ~
+   3.7.9:/home/peter/.cache/pypoetry/virtualenvs/my_project-KM_3YcvM-py3.7
+   3.7.9:/home/peter/work/venvs/long name with spaces
+   3.8.6:/home/peter/.cache/pypoetry/virtualenvs/my_project-KM_3YcvM-py3.8
+   pypy3.6-7.3.1:/home/peter/work/venvs/example1
 
-I'm not a script writer so it's probably a bit crude. It's not blazingly fast,
-since it uses a brute force scan, but on my system it only takes 3 seconds,
-and I like the simplicity.
+For example, to get a list of all versions linked to a virtual environment:
 
-I've been using it on Fedora 33 with no issues, but it could use more testing.
-In particular, users on MacOS and Windows will probably prefer the addition of
-a pretty-printing solution that doesn't rely on ``column``.
+.. code-block:: bash
+
+   $ pyenv users --raw ~ | cut -d: -f1 | uniq
+   3.7.9
+   3.8.6
+   pypy3.6-7.3.1
+
+
+Disclaimer
+----------
 
-Also, I seem to recall that not all versions of ``column`` support the ``-s``
-parameter for setting the separator. I haven't had time to research that.
+The plugin doesn't maintain a list of environments; it generates the list each
+run by performing a brute force scan of the directory for symlinks named
+`python`. This does mean it's not blazingly fast, but its simplicity provides
+state-free reliability, and in practice ``find`` only takes a few seconds.
 
-Tested with ``bash v5.0.17(1)``, ``find v4.7.0``, and ``column v2.36.1`` on
-Fedora 33.
+Also, it could really use more testing; so far I've been using it on Fedora 33
+with no issues. Tested with ``bash v5.0.17(1)`` and ``find v4.7.0``.
diff --git a/bin/pyenv-users b/bin/pyenv-users
index 8577096..aea13c9 100755
--- a/bin/pyenv-users
+++ b/bin/pyenv-users
@@ -2,49 +2,130 @@
 #
 # Summary: Find virtual environments that use pyenv-managed versions.
 #
-# Usage: pyenv users [directory]
+# Usage: pyenv users [-r|--raw] [directory]
+#
+#   -r/--raw   Raw output strings as "<version>:<venv-path>"
 #
 # Scans [directory] for virtual environments whose `python` commands
 # are symlinks back into a pyenv version. Default: current directory.
 
-if [ -n "$1" ]; then
+set -e
+
+function collect_links () {
+  # Collect all symlinks named python that point into $PYENV_ROOT
   DIR="$1"
-else
+  local -n _links=$2
+  cmd="readlink -f '{}' | grep -q ${PYENV_ROOT}"
+  unset i
+  while IFS= read -r -d $'\0' file; do
+    _links[i++]="$file"
+  done < <(find -H "$DIR" -name "python" -type l -exec sh -c "$cmd" \; -print0)
+}
+
+function collect_pairs () {
+  # Turn each link into a (version, venv) string pair
+  local -n _links=$1 _versions=$2 _venvs=$3
+
+  # Regex to extract the pyenv version from the target string. The
+  # second group consumes the actual binary (`python`, `pypy3`, etc)
+  regex="${PYENV_ROOT}/versions/(.+)/bin/(.+)"
+
+  unset i
+  for link in "${_links[@]}"; do
+    # `$link` is the `python` symlink, and `$target` is its target.
+    linkpath=$(realpath -s "$link")
+    target=$(readlink -f "$link")
+    [[ "$target" =~ $regex ]]
+    version="${BASH_REMATCH[1]}"
+    # Only capture links outside PYENV_ROOT or inside pyenv-virtualenv venvs
+    if grep -v -q "$PYENV_ROOT" <<< "$linkpath" || \
+       grep -q "$PYENV_ROOT/versions/$version/envs" <<< "$linkpath"
+    then
+      _versions[i]="$version"
+      _venvs[i++]="${link%/bin/python}"
+    fi
+  done
+}
+
+function print_pairs () {
+  # Print each (version, venv) pair
+  local -n _versions=$1 _venvs=$2
+  local -i K=${#_versions[@]} width=0 maxwidth=0
+
+  # Use the longest $version to setup the columns
+  for (( k=0; k < K; k++ )); do
+    width=${#_versions[k]}
+    if (( width > maxwidth )); then maxwidth=$width; fi
+  done
+
+  for (( k=0; k < K; k++ )); do
+    if [ -z "$RAW" ]; then
+      printf "%-*s  %s\n" "$maxwidth" "${_versions[$k]}" "${_venvs[k]}"
+    else
+      echo "${_versions[$k]}":"${_venvs[$k]}"
+    fi
+  done | sort
+}
+
+parse_options() {
+  # Parse the command line options. Taken from `pyenv-virtualenv`
+  OPTIONS=()
+  ARGUMENTS=()
+  local arg option index
+
+  for arg in "$@"; do
+    if [ "${arg:0:1}" = "-" ]; then
+      if [ "${arg:1:1}" = "-" ]; then
+        OPTIONS[${#OPTIONS[*]}]="${arg:2}"
+      else
+        index=1
+        while option="${arg:$index:1}"; do
+          [ -n "$option" ] || break
+          OPTIONS[${#OPTIONS[*]}]="$option"
+          index=$((index+1))
+        done
+      fi
+    else
+      ARGUMENTS[${#ARGUMENTS[*]}]="$arg"
+    fi
+  done
+}
+
+if [ -z "$PYENV_ROOT" ]; then
+  PYENV_ROOT=$(pyenv root)
+fi
+
+unset RAW
+parse_options "$@"
+for option in "${OPTIONS[@]}"; do
+  case "$option" in
+  "r" | "raw" )
+    RAW=true
+    ;;
+  "h" | "help" )
+    pyenv help users
+    exit 0
+    ;;
+  esac
+done
+
+if [[ "${#ARGUMENTS[@]}" == 0 ]]; then
   DIR="$PYENV_DIR"
+elif [[ "${#ARGUMENTS[@]}" == 1 ]]; then
+  DIR="${ARGUMENTS[0]}"
 fi
 
-cmd="readlink -f '{}' | grep -q ${PYENV_ROOT}"
-unset links i
-while IFS= read -r -d $'\0' file; do
-  links[i++]="$file"
-done < <(find -H "$DIR" -name "python" -type l -exec sh -c "$cmd" \; -print0)
+# The `links` are the symlink pathnames, `versions` are pyenv version strings,
+# and `venvs` are venv pathnames. Using parallel arrays since arrays-of-arrays
+# are a pain in bash. Keeping versions and venvs separate avoids needing awk.
+declare -a links versions venvs
+
+collect_links "$DIR" links
 
 # Exit if no relevant venvs were found
-if [[ $i -eq 0 ]]; then
+if [ ${#links[@]} -eq 0 ]; then
   exit 0
 fi
 
-# Use columnar output if convenient.
-if [ -n "$(command -v column)" ]; then
-  output="column -t -s ':'"
-else
-  output="cat"
-fi
-
-# Regex to extract the pyenv version from the target string. The
-# second group consumes the actual binary (`python`, `pypy3`, etc)
-regex="${PYENV_ROOT}/versions/(.+)/bin/(.+)"
-
-for link in "${links[@]}"; do
-  # `$link` is the `python` symlink, and `$target` is its target.
-  linkpath=$(realpath -s "$link")
-  target=$(readlink -f "$link")
-  [[ "$target" =~ $regex ]]
-  version="${BASH_REMATCH[1]}"
-  # Only capture links outside PYENV_ROOT or inside pyenv-virtualenv venvs
-  if grep -v -q "$PYENV_ROOT" <<< "$linkpath" || \
-     grep -q "$PYENV_ROOT/versions/$version/envs" <<< "$linkpath"
-  then
-    echo "$version":"${link%/bin/python}"
-  fi
-done | sort | $output
+collect_pairs links versions venvs
+print_pairs versions venvs

From 7042422b3c5250f14c8d86251189d9116540a512 Mon Sep 17 00:00:00 2001
From: Peter Heatwole <pfheatwole@gmail.com>
Date: Fri, 29 Jan 2021 13:52:31 -0800
Subject: [PATCH 2/5] Only accept one positional argument

---
 bin/pyenv-users | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/bin/pyenv-users b/bin/pyenv-users
index aea13c9..d6212f9 100755
--- a/bin/pyenv-users
+++ b/bin/pyenv-users
@@ -113,6 +113,9 @@ if [[ "${#ARGUMENTS[@]}" == 0 ]]; then
   DIR="$PYENV_DIR"
 elif [[ "${#ARGUMENTS[@]}" == 1 ]]; then
   DIR="${ARGUMENTS[0]}"
+else
+  pyenv help users
+  exit 1
 fi
 
 # The `links` are the symlink pathnames, `versions` are pyenv version strings,

From a2f4fc30ebd4e8d66a3d40a54745748e1456cc17 Mon Sep 17 00:00:00 2001
From: Peter Heatwole <pfheatwole@gmail.com>
Date: Fri, 29 Jan 2021 13:53:15 -0800
Subject: [PATCH 3/5] Remove unnecessary check

---
 bin/pyenv-users | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/bin/pyenv-users b/bin/pyenv-users
index d6212f9..b4de998 100755
--- a/bin/pyenv-users
+++ b/bin/pyenv-users
@@ -124,11 +124,5 @@ fi
 declare -a links versions venvs
 
 collect_links "$DIR" links
-
-# Exit if no relevant venvs were found
-if [ ${#links[@]} -eq 0 ]; then
-  exit 0
-fi
-
 collect_pairs links versions venvs
 print_pairs versions venvs

From ca173a51ed19df466451a4b2393239ab2fae7df2 Mon Sep 17 00:00:00 2001
From: Peter Heatwole <pfheatwole@gmail.com>
Date: Fri, 29 Jan 2021 13:53:37 -0800
Subject: [PATCH 4/5] Tidy

---
 README.rst      | 10 +---------
 bin/pyenv-users |  1 -
 2 files changed, 1 insertion(+), 10 deletions(-)

diff --git a/README.rst b/README.rst
index 525dd1c..011215f 100644
--- a/README.rst
+++ b/README.rst
@@ -24,17 +24,9 @@ Prerequisites
 Installation
 ------------
 
-Verify that ``$PYENV_ROOT`` has been configured:
-
-.. code-block:: bash
-
-   $ echo $PYENV_ROOT
-
-Install the plugin:
-
 .. code-block:: bash
 
-   $ git clone https://github.com/pyenv/pyenv-users.git "$PYENV_ROOT"/plugins/pyenv-users
+   $ git clone https://github.com/pyenv/pyenv-users.git "$(pyenv root)/plugins/pyenv-users"
 
 
 Usage
diff --git a/bin/pyenv-users b/bin/pyenv-users
index b4de998..160ad57 100755
--- a/bin/pyenv-users
+++ b/bin/pyenv-users
@@ -122,7 +122,6 @@ fi
 # and `venvs` are venv pathnames. Using parallel arrays since arrays-of-arrays
 # are a pain in bash. Keeping versions and venvs separate avoids needing awk.
 declare -a links versions venvs
-
 collect_links "$DIR" links
 collect_pairs links versions venvs
 print_pairs versions venvs

From fb86cb02b74cf2361a2a052796f6b59c9cfffa77 Mon Sep 17 00:00:00 2001
From: Peter Heatwole <pfheatwole@gmail.com>
Date: Fri, 29 Jan 2021 22:05:39 -0800
Subject: [PATCH 5/5] Simplify by eliminating unnecessary functions

The functions were only called once and only served to make the script
more difficult to read. Relying on IN/OUT parameters in particular just
wasn't worth the readability cost.
---
 README.rst      |   2 -
 bin/pyenv-users | 109 ++++++++++++++++++++----------------------------
 2 files changed, 46 insertions(+), 65 deletions(-)

diff --git a/README.rst b/README.rst
index 011215f..f72094b 100644
--- a/README.rst
+++ b/README.rst
@@ -14,8 +14,6 @@ virtual environments, regardless of how they were created (``python -m venv
 Prerequisites
 -------------
 
-* BASH >= 4.3 (for ``nameref`` parameters)
-
 * GNU coreutils (for ``readlink`` and ``realpath``)
 
 * GNU findutils (for ``find``)
diff --git a/bin/pyenv-users b/bin/pyenv-users
index 160ad57..f4dfa90 100755
--- a/bin/pyenv-users
+++ b/bin/pyenv-users
@@ -11,62 +11,6 @@
 
 set -e
 
-function collect_links () {
-  # Collect all symlinks named python that point into $PYENV_ROOT
-  DIR="$1"
-  local -n _links=$2
-  cmd="readlink -f '{}' | grep -q ${PYENV_ROOT}"
-  unset i
-  while IFS= read -r -d $'\0' file; do
-    _links[i++]="$file"
-  done < <(find -H "$DIR" -name "python" -type l -exec sh -c "$cmd" \; -print0)
-}
-
-function collect_pairs () {
-  # Turn each link into a (version, venv) string pair
-  local -n _links=$1 _versions=$2 _venvs=$3
-
-  # Regex to extract the pyenv version from the target string. The
-  # second group consumes the actual binary (`python`, `pypy3`, etc)
-  regex="${PYENV_ROOT}/versions/(.+)/bin/(.+)"
-
-  unset i
-  for link in "${_links[@]}"; do
-    # `$link` is the `python` symlink, and `$target` is its target.
-    linkpath=$(realpath -s "$link")
-    target=$(readlink -f "$link")
-    [[ "$target" =~ $regex ]]
-    version="${BASH_REMATCH[1]}"
-    # Only capture links outside PYENV_ROOT or inside pyenv-virtualenv venvs
-    if grep -v -q "$PYENV_ROOT" <<< "$linkpath" || \
-       grep -q "$PYENV_ROOT/versions/$version/envs" <<< "$linkpath"
-    then
-      _versions[i]="$version"
-      _venvs[i++]="${link%/bin/python}"
-    fi
-  done
-}
-
-function print_pairs () {
-  # Print each (version, venv) pair
-  local -n _versions=$1 _venvs=$2
-  local -i K=${#_versions[@]} width=0 maxwidth=0
-
-  # Use the longest $version to setup the columns
-  for (( k=0; k < K; k++ )); do
-    width=${#_versions[k]}
-    if (( width > maxwidth )); then maxwidth=$width; fi
-  done
-
-  for (( k=0; k < K; k++ )); do
-    if [ -z "$RAW" ]; then
-      printf "%-*s  %s\n" "$maxwidth" "${_versions[$k]}" "${_venvs[k]}"
-    else
-      echo "${_versions[$k]}":"${_venvs[$k]}"
-    fi
-  done | sort
-}
-
 parse_options() {
   # Parse the command line options. Taken from `pyenv-virtualenv`
   OPTIONS=()
@@ -91,10 +35,6 @@ parse_options() {
   done
 }
 
-if [ -z "$PYENV_ROOT" ]; then
-  PYENV_ROOT=$(pyenv root)
-fi
-
 unset RAW
 parse_options "$@"
 for option in "${OPTIONS[@]}"; do
@@ -114,14 +54,57 @@ if [[ "${#ARGUMENTS[@]}" == 0 ]]; then
 elif [[ "${#ARGUMENTS[@]}" == 1 ]]; then
   DIR="${ARGUMENTS[0]}"
 else
+  echo -e "\nToo many directory arguments.\n"
   pyenv help users
   exit 1
 fi
 
+# ----------------------------------------------------------------------------
+# Finished parsing the arguments. Begin the actual functionality.
+
 # The `links` are the symlink pathnames, `versions` are pyenv version strings,
 # and `venvs` are venv pathnames. Using parallel arrays since arrays-of-arrays
 # are a pain in bash. Keeping versions and venvs separate avoids needing awk.
 declare -a links versions venvs
-collect_links "$DIR" links
-collect_pairs links versions venvs
-print_pairs versions venvs
+
+if [ -z "$PYENV_ROOT" ]; then
+  PYENV_ROOT=$(pyenv root)
+fi
+
+# Collect all symlinks named `python` that point into $PYENV_ROOT
+cmd="readlink -f '{}' | grep -q ${PYENV_ROOT}"
+unset i
+while IFS= read -r -d $'\0' file; do
+  links[i++]="$file"
+done < <(find -H "$DIR" -name "python" -type l -exec sh -c "$cmd" \; -print0)
+
+# Turn each link into a (version, venv) string pair
+regex="${PYENV_ROOT}/versions/(.+)/bin/(.+)"
+unset i
+for link in "${links[@]}"; do
+  linkpath=$(realpath -s "$link")
+  target=$(readlink -f "$link")
+  [[ "$target" =~ $regex ]]
+  version="${BASH_REMATCH[1]}"
+  # Only capture links outside PYENV_ROOT or inside pyenv-virtualenv venvs
+  if grep -v -q "$PYENV_ROOT" <<< "$linkpath" || \
+     grep -q "$PYENV_ROOT/versions/$version/envs" <<< "$linkpath"
+  then
+    versions[i]="$version"
+    venvs[i++]="${link%/bin/python}"
+  fi
+done
+
+# Print each (version, venv) pair
+declare -i K=${#versions[@]} width=0 maxwidth=0
+for (( k=0; k < K; k++ )); do
+  width=${#versions[k]}
+  if (( width > maxwidth )); then maxwidth=$width; fi
+done
+for (( k=0; k < K; k++ )); do
+  if [ -z "$RAW" ]; then
+    printf "%-*s  %s\n" "$maxwidth" "${versions[$k]}" "${venvs[k]}"
+  else
+    echo "${versions[$k]}":"${venvs[$k]}"
+  fi
+done | sort