fix(cli): address review feedback on omz generate plugin

- Turn %placeholders% into private markers when a template is read and
  strip the marker from every value, so text inserted from user input
  (e.g. -d '%name%') is never rescanned as a placeholder.
- When --enable is used for a name already in $plugins (a custom
  override of an enabled built-in), report it and reload instead of
  failing in _omz::plugin::enable.
- Make the completion note accurate whether or not a _<cmd> file was
  generated.
- Test the write-phase cleanup with a template set missing a later
  template, and test that placeholder-looking values come out literally.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.github/workflows/main.yml

@@ -38,6 +38,7 @@ jobs:
                       ./lib/*.zsh \
                       ./plugins/*/*.plugin.zsh \
                       ./plugins/*/_* \
+                      ./templates/generators/*/*.zsh-template \
                       ./themes/*.zsh-theme; do
             zsh -n "$file" || return 1
           done

README.md

@@ -346,6 +346,10 @@ directory.
 If you have many functions that go well together, you can put them as a `XYZ.plugin.zsh` file in the
 `custom/plugins/` directory and then enable this plugin.
 
+The quickest way to start one is `omz generate plugin <name>`. It creates the plugin directory with a
+commented `<name>.plugin.zsh`, a `README.md`, and (for plugins that wrap a command-line tool) a completion
+skeleton, then tells you how to try it out.
+
 If you would like to override the functionality of a plugin distributed with Oh My Zsh, create a plugin of the
 same name in the `custom/plugins/` directory and it will be loaded instead of the one in `plugins/`.
 

lib/cli.zsh

@@ -24,6 +24,7 @@ function _omz {
   local -a cmds subcmds
   cmds=(
     'changelog:Print the changelog'
+    'generate:Run a generator, e.g. to create a custom plugin'
     'help:Usage information'
     'plugin:Manage plugins'
     'pr:Manage Oh My Zsh Pull Requests'
@@ -41,6 +42,8 @@ function _omz {
       changelog) local -a refs
         refs=("${(@f)$(builtin cd -q "$ZSH"; command git for-each-ref --format="%(refname:short):%(subject)" refs/heads refs/tags)}")
         _describe 'command' refs ;;
+      generate) subcmds=('plugin:Create a custom plugin')
+        _describe 'generator' subcmds ;;
       plugin) subcmds=(
         'disable:Disable plugin(s)'
         'enable:Enable plugin(s)'
@@ -56,6 +59,8 @@ function _omz {
     esac
   elif (( CURRENT == 4 )); then
     case "${words[2]}::${words[3]}" in
+      generate::plugin)
+        _omz::generate::plugin::complete_options ;;
       plugin::(disable|enable|load))
         local -aU valid_plugins
 
@@ -84,6 +89,8 @@ function _omz {
     esac
   elif (( CURRENT > 4 )); then
     case "${words[2]}::${words[3]}" in
+      generate::plugin)
+        _omz::generate::plugin::complete_options ;;
       plugin::(enable|disable|load))
         local -aU valid_plugins
 
@@ -169,15 +176,16 @@ Usage: omz <command> [options]
 
 Available commands:
 
-  help                Print this help message
-  changelog           Print the changelog
-  plugin <command>    Manage plugins
-  pr     <command>    Manage Oh My Zsh Pull Requests
-  reload              Reload the current zsh session
-  shop                Open the Oh My Zsh shop
-  theme  <command>    Manage themes
-  update              Update Oh My Zsh
-  version             Show the version
+  help                  Print this help message
+  changelog             Print the changelog
+  generate <generator>  Run a generator, e.g. to create a custom plugin
+  plugin <command>      Manage plugins
+  pr     <command>      Manage Oh My Zsh Pull Requests
+  reload                Reload the current zsh session
+  shop                  Open the Oh My Zsh shop
+  theme  <command>      Manage themes
+  update                Update Oh My Zsh
+  version               Show the version
 
 EOF
 }
@@ -202,6 +210,371 @@ EOF
   ZSH="$ZSH" command zsh -f "$ZSH/tools/changelog.sh" "$version" "${2:-}" "$format"
 }
 
+function _omz::generate {
+  (( $# > 0 && $+functions[$0::$1] )) || {
+    cat >&2 <<EOF
+Usage: ${(j: :)${(s.::.)0#_}} <generator> [options]
+
+Available generators:
+
+  plugin [<name>]  Create a custom plugin in \$ZSH_CUSTOM/plugins
+
+EOF
+    return 1
+  }
+
+  local command="$1"
+  shift
+
+  $0::$command "$@"
+}
+
+function _omz::generate::plugin {
+  setopt localoptions extendedglob
+
+  local -A opts
+  zparseopts -D -E -A opts -- d: -description: c: -command: -no-completion -enable y -yes h -help || return 1
+
+  if (( ${+opts[-h]} || ${+opts[--help]} )); then
+    _omz::generate::plugin::usage
+    return 0
+  fi
+
+  # zparseopts -E leaves anything it doesn't recognise in $@
+  local arg
+  for arg in "$@"; do
+    if [[ "$arg" == -* ]]; then
+      _omz::log error "unknown option '$arg'."
+      _omz::generate::plugin::usage
+      return 1
+    fi
+  done
+  if (( $# > 1 )); then
+    _omz::generate::plugin::usage
+    return 1
+  fi
+
+  # Only ask questions when there is someone there to answer them
+  local interactive=0
+  if [[ -o interactive && -t 0 ]] && (( ! ${+opts[-y]} && ! ${+opts[--yes]} )); then
+    interactive=1
+  fi
+
+  local custom="${ZSH_CUSTOM:-${ZSH:+$ZSH/custom}}"
+  if [[ -z "$custom" ]]; then
+    _omz::log error "\$ZSH is not set. Is Oh My Zsh loaded?"
+    return 1
+  fi
+
+  local templates="$ZSH/templates/generators/plugin"
+  if [[ ! -d "$templates" ]]; then
+    _omz::log error "templates not found at '${templates/#$HOME/\~}'. Try running 'omz update'."
+    return 1
+  fi
+
+  # Check we can write to $ZSH_CUSTOM/plugins, or the closest directory that exists
+  local probe="$custom/plugins"
+  while [[ ! -e "$probe" && "$probe" != "${probe:h}" ]]; do
+    probe="${probe:h}"
+  done
+  if [[ ! -w "$probe" ]]; then
+    _omz::log error "cannot write to '${probe/#$HOME/\~}'. Set \$ZSH_CUSTOM to a directory you own."
+    return 1
+  fi
+
+  ## Gather answers. Nothing is written until all of them are in.
+
+  local name="$1" attempts=0
+  if [[ -n "$name" ]]; then
+    _omz::generate::plugin::validate_name "$name" || return 1
+  elif (( interactive )); then
+    while true; do
+      _omz::generate::plugin::ask "Plugin name" || return 1
+      name="$REPLY"
+      _omz::generate::plugin::validate_name "$name" && break
+      if (( ++attempts >= 3 )); then
+        _omz::log error "giving up."
+        return 1
+      fi
+    done
+  else
+    _omz::generate::plugin::usage
+    return 1
+  fi
+
+  local dir="$custom/plugins/$name"
+  if [[ -e "$dir" ]]; then
+    _omz::log error "'$name' already exists at '${dir/#$HOME/\~}'. Remove it or pick another name."
+    return 1
+  fi
+  if [[ -d "$ZSH/plugins/$name" ]]; then
+    _omz::log warn "'$name' is also a built-in plugin. Your custom plugin will override it."
+    if (( interactive )); then
+      _omz::confirm "Continue? [y/N] "
+      if [[ "$REPLY" != [yY] ]]; then
+        _omz::log info "aborted."
+        return 1
+      fi
+    fi
+  fi
+
+  local description="${opts[-d]:-${opts[--description]:-}}"
+  if [[ -z "$description" ]]; then
+    description="$name plugin for Oh My Zsh"
+    if (( interactive )); then
+      _omz::generate::plugin::ask "Short description" "$description" || return 1
+      description="$REPLY"
+    fi
+  fi
+  # The description goes into a comment and a README line: keep it on one line
+  description="${description//[[:cntrl:]]/ }"
+
+  local cmd="${opts[-c]:-${opts[--command]:-}}"
+  if [[ -n "$cmd" ]]; then
+    _omz::generate::plugin::validate_command "$cmd" || return 1
+  elif (( interactive )); then
+    local default_cmd=""
+    (( $+commands[$name] )) && default_cmd="$name"
+    attempts=0
+    while true; do
+      if [[ -n "$default_cmd" ]]; then
+        _omz::generate::plugin::ask "Command-line tool this plugin wraps (or 'none')" "$default_cmd" || return 1
+      else
+        _omz::generate::plugin::ask "Command-line tool this plugin wraps (blank for none)" || return 1
+      fi
+      cmd="$REPLY"
+      [[ "$cmd" != (none|-) ]] || cmd=""
+      [[ -n "$cmd" ]] || break
+      _omz::generate::plugin::validate_command "$cmd" && break
+      if (( ++attempts >= 3 )); then
+        _omz::log error "giving up."
+        return 1
+      fi
+    done
+  fi
+
+  # completion: "" (none), "file" (a _<cmd> skeleton) or "cached" (the tool generates it)
+  local completion="" compgen=""
+  if [[ -n "$cmd" ]] && (( ! ${+opts[--no-completion]} )); then
+    completion=file
+    if (( interactive )); then
+      _omz::confirm "Add a completion function for $cmd? [Y/n] "
+      if [[ "$REPLY" == [nN] ]]; then
+        completion=""
+      else
+        _omz::confirm "Does $cmd generate its own zsh completion (e.g. '$cmd completion zsh')? [y/N] "
+        if [[ "$REPLY" == [yY] ]]; then
+          completion=cached
+          _omz::generate::plugin::ask "Command that prints the completion script" "$cmd completion zsh" || return 1
+          compgen="$REPLY"
+        fi
+      fi
+    fi
+  fi
+
+  local enable=${+opts[--enable]}
+  if (( interactive && ! enable )); then
+    _omz::confirm "Add $name to plugins=() in your .zshrc now? [y/N] "
+    [[ "$REPLY" != [yY] ]] || enable=1
+  fi
+
+  ## Write the files. If anything fails, remove only what we created.
+
+  local -a created
+  local block="" cache="" ok=0
+  {
+    if [[ ! -d "$custom/plugins" ]]; then
+      command mkdir -p "$custom/plugins" || return 1
+      _omz::generate::plugin::created "$custom/plugins"
+    fi
+    command mkdir "$dir" || return 1
+    _omz::generate::plugin::created "$dir"
+
+    local plugin_tpl=plugin.zsh-template readme_tpl=README.md-template
+    if [[ -z "$cmd" ]]; then
+      plugin_tpl=plugin-generic.zsh-template
+      readme_tpl=README-generic.md-template
+    elif [[ "$completion" == cached ]]; then
+      block="$(_omz::generate::plugin::template completion-cached.zsh-template)" || return 1
+      cache="$(_omz::generate::plugin::template README-cache.md-template)" || return 1
+    else
+      block="$(_omz::generate::plugin::template completion-note.zsh-template)" || return 1
+    fi
+
+    _omz::generate::plugin::render "$plugin_tpl" "$dir/$name.plugin.zsh" || return 1
+    _omz::generate::plugin::render "$readme_tpl" "$dir/README.md" || return 1
+    if [[ "$completion" == file ]]; then
+      _omz::generate::plugin::render completion.zsh-template "$dir/_$cmd" || return 1
+    fi
+    ok=1
+  } always {
+    if (( ! ok )); then
+      _omz::log error "could not generate the plugin. Cleaning up..."
+      (( ${#created} )) && command rm -f -- "${created[@]}"
+      [[ ! -d "$dir" ]] || command rmdir -- "$dir" 2>/dev/null
+    fi
+  }
+
+  print
+  _omz::log info "plugin '$name' generated."
+  print
+  print -r -- "Next steps:"
+  print
+  print -r -- "  1. Edit it:     ${EDITOR:-vim} ${dir/#$HOME/\~}/$name.plugin.zsh"
+  print -r -- "  2. Try it now:  omz plugin load $name"
+  (( enable )) || print -r -- "  3. Keep it:     omz plugin enable $name"
+  print
+  print -r -- "Docs: https://github.com/ohmyzsh/ohmyzsh/wiki/Customization#overriding-and-adding-plugins"
+
+  # Last thing we do: in an interactive shell this restarts zsh
+  if (( enable )); then
+    print
+    if (( ${plugins[(Ie)$name]} )); then
+      # Already enabled (e.g. a custom override of a built-in): just reload
+      _omz::log info "'$name' is already in your plugins list."
+      [[ ! -o interactive ]] || _omz::reload
+    else
+      _omz::plugin::enable "$name"
+    fi
+  fi
+}
+
+function _omz::generate::plugin::usage {
+  cat >&2 <<EOF
+Usage: omz generate plugin [<name>] [options]
+
+Creates a custom plugin in \$ZSH_CUSTOM/plugins/<name>. Anything not given as an
+option is asked for interactively. In a non-interactive shell (or with --yes)
+defaults are used instead.
+
+Options:
+  -d, --description <text>  One-line description for the README and file header
+  -c, --command <cmd>       Command-line tool this plugin wraps. Adds a check
+                            that it is installed and scaffolds its completion
+      --no-completion       Don't scaffold a completion function
+      --enable              Add the plugin to plugins=() in .zshrc when done
+                            (restarts your shell)
+  -y, --yes                 Never prompt; use defaults for anything not given
+  -h, --help                Show this help
+
+EOF
+}
+
+function _omz::generate::plugin::complete_options {
+  local -a opts
+  opts=(
+    '--description:One-line description for the README'
+    '--command:Command-line tool this plugin wraps'
+    '--no-completion:Skip the completion scaffold'
+    '--enable:Enable the plugin when done'
+    '--yes:Never prompt'
+  )
+  _describe -o 'options' opts
+}
+
+# The name ends up in a mkdir path and, via --enable, inside the awk script that
+# rewrites .zshrc. This is the one place it gets checked.
+function _omz::generate::plugin::validate_name {
+  setopt localoptions extendedglob
+  local name="$1"
+
+  if [[ -z "$name" ]]; then
+    _omz::log error "plugin name cannot be empty."
+  elif (( ${#name} > 64 )); then
+    _omz::log error "plugin name is too long (64 characters max)."
+  elif [[ "$name" != "${name:l}" ]]; then
+    _omz::log error "plugin names must be lowercase. Did you mean '${name:l}'?"
+  elif [[ "$name" != [a-z0-9][a-z0-9_-]# ]]; then
+    _omz::log error "invalid plugin name: use only lowercase letters, digits, '-' and '_', starting with a letter or digit."
+  else
+    return 0
+  fi
+  return 1
+}
+
+# The command name ends up in $+commands[...], _comps[...] and a filename
+function _omz::generate::plugin::validate_command {
+  setopt localoptions extendedglob
+
+  if (( ${#1} > 64 )) || [[ "$1" != [[:alnum:]_][[:alnum:]_.+-]# ]]; then
+    _omz::log error "invalid command name: use only letters, digits, '.', '_', '+' and '-'."
+    return 1
+  fi
+}
+
+# Ask a question and leave the answer in $REPLY. An empty answer takes the
+# default. Returns 1 when there is no more input (Ctrl-D).
+function _omz::generate::plugin::ask {
+  setopt localoptions extendedglob
+  local question="$1" default="$2"
+  [[ -z "$default" ]] || question+=" [$default]"
+
+  _omz::log prompt "$question: " "omz::generate::plugin"
+  if ! builtin read -r; then
+    print >&2
+    _omz::log info "aborted." "omz::generate::plugin"
+    return 1
+  fi
+
+  [[ -n "$REPLY" ]] || REPLY="$default"
+  # Answers are single-line values: flatten control characters and trim
+  REPLY="${REPLY//[[:cntrl:]]/ }"
+  REPLY="${${REPLY##[[:space:]]#}%%[[:space:]]#}"
+}
+
+# Print a template file with its %placeholders% turned into private markers,
+# or explain which one is missing
+function _omz::generate::plugin::template {
+  if [[ ! -f "$templates/$1" ]]; then
+    _omz::log error "missing template '${templates/#$HOME/\~}/$1'." "omz::generate::plugin"
+    return 1
+  fi
+
+  local content="$(<"$templates/$1")" token m=$'\x1f'
+  for token in completion cache name command description compgen; do
+    content="${content//\%${token}\%/${m}${token}${m}}"
+  done
+  print -r -- "$content"
+}
+
+# Fill in the placeholders of a template and write it to a file. Values come
+# from the caller: $name, $cmd, $description, $compgen, $block and $cache.
+#
+# Placeholders are matched as the markers that ::template produced, and the
+# marker character is stripped from every value, so a value that happens to
+# look like a placeholder (e.g. -d '%name%') is written out literally.
+function _omz::generate::plugin::render {
+  setopt localoptions extendedglob
+  local content m=$'\x1f'
+  content="$(_omz::generate::plugin::template "$1")" || return 1
+
+  # Blocks go first: they are templates too and carry markers of their own
+  content="${content//${m}completion${m}/$block}"
+  content="${content//${m}cache${m}/$cache}"
+  content="${content//${m}name${m}/${name//$m/}}"
+  content="${content//${m}command${m}/${cmd//$m/}}"
+  content="${content//${m}description${m}/${description//$m/}}"
+  content="${content//${m}compgen${m}/${compgen//$m/}}"
+  # Drop blank lines left behind by an empty placeholder at the end
+  content="${content%%$'\n'##}"
+
+  created+=("$2")
+  print -r -- "$content" > "$2" || return 1
+  _omz::generate::plugin::created "$2"
+}
+
+function _omz::generate::plugin::created {
+  # Colour the verb with print -P, but print the path with print -r so that a
+  # '%' somewhere in the path isn't treated as a prompt escape.
+  # Keep the output plain when it is being piped.
+  if [[ -t 1 ]]; then
+    print -Pn "      %F{green}create%f  "
+  else
+    print -n "      create  "
+  fi
+  print -r -- "${1/#$HOME/\~}"
+}
+
 function _omz::plugin {
   (( $# > 0 && $+functions[$0::$1] )) || {
     cat >&2 <<EOF

lib/tests/generate-plugin.test.zsh

@@ -0,0 +1,198 @@
+#!/usr/bin/zsh -df
+
+# Tests for `omz generate plugin`. Run with: zsh lib/tests/generate-plugin.test.zsh
+
+ZSH="${0:A:h:h:h}"
+ZSH_CUSTOM="$(mktemp -d)"
+trap 'command rm -rf "$ZSH_CUSTOM"' EXIT
+
+source "$ZSH/lib/cli.zsh"
+
+failures=0
+pass() { print -u2 "\e[32mSuccess\e[0m: $1" }
+fail() { print -u2 "\e[31mError\e[0m: $1"; (( failures++ )) }
+
+# assert_files <plugin> <expected files, space separated>
+assert_files() {
+  local actual="$(print -l "$ZSH_CUSTOM"/plugins/$1/*(N:t) "$ZSH_CUSTOM"/plugins/$1/_*(N:t) | sort -u | tr '\n' ' ')"
+  local expected="$(print -l ${=2} | sort -u | tr '\n' ' ')"
+  if [[ "$actual" == "$expected" ]]; then
+    pass "$1 has files: $expected"
+  else
+    fail "$1 has files '$actual', expected '$expected'"
+  fi
+}
+
+# assert_syntax <plugin>: every generated file must pass zsh -n, like CI does
+assert_syntax() {
+  local file
+  for file in "$ZSH_CUSTOM"/plugins/$1/*.plugin.zsh(N) "$ZSH_CUSTOM"/plugins/$1/_*(N); do
+    if zsh -n "$file"; then
+      pass "${file:t} passes zsh -n"
+    else
+      fail "${file:t} fails zsh -n"
+    fi
+  done
+}
+
+# assert_contains <file> <literal string>
+assert_contains() {
+  if grep -qF -- "$2" "$1"; then
+    pass "${1:t} contains '$2'"
+  else
+    fail "${1:t} does not contain '$2'"
+  fi
+}
+
+## Templates must be valid zsh even before substitution (CI checks this too)
+
+for file in "$ZSH"/templates/generators/plugin/*.zsh-template; do
+  if zsh -n "$file"; then
+    pass "template ${file:t} passes zsh -n"
+  else
+    fail "template ${file:t} fails zsh -n"
+  fi
+done
+
+## A plugin that wraps a command
+
+description='Shortcuts & stuff $(id) `id` 100%'
+if omz generate plugin foo -d "$description" -c foo --yes >/dev/null 2>&1; then
+  pass "generates a command-wrapping plugin"
+else
+  fail "generating a command-wrapping plugin failed"
+fi
+assert_files foo "README.md _foo foo.plugin.zsh"
+assert_syntax foo
+assert_contains "$ZSH_CUSTOM/plugins/foo/README.md" 'plugins=(... foo)'
+assert_contains "$ZSH_CUSTOM/plugins/foo/README.md" "$description"
+assert_contains "$ZSH_CUSTOM/plugins/foo/foo.plugin.zsh" "$description"
+assert_contains "$ZSH_CUSTOM/plugins/foo/foo.plugin.zsh" '$+commands[foo]'
+assert_contains "$ZSH_CUSTOM/plugins/foo/_foo" '#compdef foo'
+if grep -q '%[a-z]*%' "$ZSH_CUSTOM"/plugins/foo/*; then
+  fail "foo still has unfilled placeholders"
+else
+  pass "foo has no unfilled placeholders"
+fi
+
+## Values that look like placeholders are written literally
+
+omz generate plugin lit -d '%compgen% and %name% stay' -c lit --yes >/dev/null 2>&1
+assert_contains "$ZSH_CUSTOM/plugins/lit/README.md" '%compgen% and %name% stay'
+assert_contains "$ZSH_CUSTOM/plugins/lit/lit.plugin.zsh" '%compgen% and %name% stay'
+
+## A plugin with no command
+
+if omz generate plugin bar --yes >/dev/null 2>&1; then
+  pass "generates a generic plugin"
+else
+  fail "generating a generic plugin failed"
+fi
+assert_files bar "README.md bar.plugin.zsh"
+assert_syntax bar
+assert_contains "$ZSH_CUSTOM/plugins/bar/README.md" 'This plugin does not add any aliases.'
+assert_contains "$ZSH_CUSTOM/plugins/bar/bar.plugin.zsh" 'bar plugin for Oh My Zsh'
+
+## --no-completion, and the rails-style output
+
+output="$(omz generate plugin baz -c baz --no-completion --yes 2>/dev/null)"
+assert_files baz "README.md baz.plugin.zsh"
+create_lines=$(print -r -- "$output" | grep -c '^      create  ')
+if (( create_lines == 3 )); then
+  pass "prints one create line per path"
+else
+  fail "expected 3 create lines, got $create_lines"
+fi
+if [[ "$output" == *"omz plugin load baz"* ]]; then
+  pass "prints next steps"
+else
+  fail "next steps missing from output"
+fi
+
+## Bad names are rejected without touching the filesystem
+
+before="$(print -l "$ZSH_CUSTOM"/plugins/*(N:t))"
+for bad in '' 'Foo' 'a b' '../evil' 'a/b' '.hidden' '.' '..' '-x' 'foo`id`' 'foo"$(id)"' $'a\nb' "$(printf 'x%.0s' {1..65})"; do
+  if omz generate plugin "$bad" --yes >/dev/null 2>&1; then
+    fail "accepted bad name ${(qq)bad}"
+  else
+    pass "rejected bad name ${(qq)bad}"
+  fi
+done
+after="$(print -l "$ZSH_CUSTOM"/plugins/*(N:t))"
+if [[ "$before" == "$after" ]]; then
+  pass "bad names created nothing"
+else
+  fail "bad names changed \$ZSH_CUSTOM/plugins"
+fi
+
+## Bad command names are rejected
+
+for bad in 'a b' '../x' 'foo;id' 'foo$(id)'; do
+  if omz generate plugin qux -c "$bad" --yes >/dev/null 2>&1; then
+    fail "accepted bad command ${(qq)bad}"
+  else
+    pass "rejected bad command ${(qq)bad}"
+  fi
+done
+
+## Existing plugin, unknown option, missing templates
+
+if omz generate plugin foo --yes >/dev/null 2>&1; then
+  fail "overwrote an existing plugin"
+else
+  pass "refuses to overwrite an existing plugin"
+fi
+
+if omz generate plugin quux --bogus --yes >/dev/null 2>&1; then
+  fail "accepted an unknown option"
+else
+  pass "rejects an unknown option"
+fi
+
+if ( ZSH=/nonexistent; omz generate plugin quux --yes >/dev/null 2>&1 ); then
+  fail "ran without templates"
+else
+  pass "fails cleanly when templates are missing"
+fi
+[[ -e "$ZSH_CUSTOM/plugins/quux" ]] && fail "quux was created by a failed run"
+
+## A failure after the first file is written removes everything it created
+
+broken="$(mktemp -d)"
+mkdir -p "$broken/templates/generators/plugin" "$broken/plugins"
+cp "$ZSH/templates/generators/plugin/plugin.zsh-template" \
+   "$ZSH/templates/generators/plugin/completion-note.zsh-template" "$broken/templates/generators/plugin/"
+# README.md-template is missing, so the plugin file is written and then the README fails
+if ( ZSH="$broken"; omz generate plugin partial -c partial --yes >/dev/null 2>&1 ); then
+  fail "succeeded with a missing README template"
+else
+  pass "fails when a later template is missing"
+fi
+if [[ -e "$ZSH_CUSTOM/plugins/partial" ]]; then
+  fail "partial plugin directory was left behind: $(ls "$ZSH_CUSTOM/plugins/partial")"
+else
+  pass "cleans up the partial plugin directory"
+fi
+command rm -rf "$broken"
+
+## The prompt helper
+
+_omz::generate::plugin::ask "Q" "dflt" 2>/dev/null < <(print '')
+[[ "$REPLY" == "dflt" ]] && pass "ask: empty answer takes the default" || fail "ask: got '$REPLY', expected 'dflt'"
+
+_omz::generate::plugin::ask "Q" "dflt" 2>/dev/null < <(print '  hi there  ')
+[[ "$REPLY" == "hi there" ]] && pass "ask: trims whitespace" || fail "ask: got '$REPLY', expected 'hi there'"
+
+if _omz::generate::plugin::ask "Q" 2>/dev/null < /dev/null; then
+  fail "ask: did not fail on EOF"
+else
+  pass "ask: fails on EOF"
+fi
+
+print -u2
+if (( failures )); then
+  print -u2 "\e[31m$failures test(s) failed\e[0m"
+  exit 1
+fi
+print -u2 "\e[32mAll tests passed\e[0m"

templates/generators/plugin/README-cache.md-template

@@ -0,0 +1,7 @@
+
+## Cache
+
+This plugin caches the completion script and automatically updates it when the
+plugin is loaded, which is usually when you start a new terminal emulator.
+
+The cache is stored at `$ZSH_CACHE_DIR/completions/_%command%`.

templates/generators/plugin/README-generic.md-template

@@ -0,0 +1,11 @@
+# %name% plugin
+
+%description%
+
+To use it, add `%name%` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... %name%)
+```
+
+This plugin does not add any aliases.

templates/generators/plugin/README.md-template

@@ -0,0 +1,20 @@
+# %name% plugin
+
+%description%
+
+To use it, add `%name%` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... %name%)
+```
+
+## Aliases
+
+| Alias        | Command            | Description           |
+| :----------- | ------------------ | :-------------------- |
+| `%command%s` | `%command% status` | Show %command% status |
+
+## Requirements
+
+This plugin requires [%command%](https://example.com) to be installed.
+%cache%

templates/generators/plugin/completion-cached.zsh-template

@@ -0,0 +1,22 @@
+#
+# Completion
+#
+# %command% generates its own zsh completion, so we cache it instead of
+# maintaining a `_%command%` file by hand.
+#
+# On the first shell after installing this plugin the cache file doesn't exist
+# yet, so compinit hasn't bound it. Do that manually here.
+if [[ ! -f "$ZSH_CACHE_DIR/completions/_%command%" ]]; then
+  typeset -g -A _comps
+  autoload -Uz _%command%
+  _comps[%command%]=_%command%
+fi
+
+# Regenerate the cache in the background so it never blocks shell startup.
+# TMPPREFIX puts the temp file next to the destination, which keeps the move
+# atomic.
+zmodload -F zsh/files b:zf_mv
+() {
+  local TMPPREFIX="$ZSH_CACHE_DIR/completions/_%command%"
+  zf_mv -f -- =( %compgen% ) "$TMPPREFIX"
+} &|

templates/generators/plugin/completion-note.zsh-template

@@ -0,0 +1,6 @@
+#
+# Completion
+#
+# Oh My Zsh adds this directory to $fpath, so a file named `_%command%` next to
+# this one is picked up automatically as the completion for %command%.
+#

templates/generators/plugin/completion.zsh-template

@@ -0,0 +1,32 @@
+#compdef %command%
+#
+# Completion for %command%.
+#
+# This is a starting point. Delete what you don't need. Two references:
+#   https://zsh.sourceforge.io/Doc/Release/Completion-System.html
+#   https://github.com/zsh-users/zsh/blob/master/Etc/completion-style-guide
+
+local -a subcommands
+subcommands=(
+  'status:Show the current status'
+  'run:Run something'
+  'help:Show help for a command'
+)
+
+_arguments -C \
+  '(-h --help)'{-h,--help}'[show help]' \
+  '(-v --version)'{-v,--version}'[show the version]' \
+  '1: :->subcommand' \
+  '*:: :->args'
+
+case $state in
+  subcommand)
+    _describe -t commands '%command% subcommand' subcommands
+    ;;
+  args)
+    case $words[1] in
+      status) _arguments '--short[one-line output]' ;;
+      run)    _files ;;
+    esac
+    ;;
+esac

templates/generators/plugin/plugin-generic.zsh-template

@@ -0,0 +1,48 @@
+# %name% plugin
+#
+# %description%
+#
+# This file is sourced by Oh My Zsh in every new shell, so keep it fast.
+# Avoid running external commands at the top level unless you really need to.
+#
+# Wrapping a command-line tool? Guard everything so people who don't have it
+# installed don't end up with broken aliases:
+#
+# if (( ! $+commands[sometool] )); then
+#   return
+# fi
+
+#
+# Aliases
+#
+# Document every alias in README.md. Short, obvious, and few beats many.
+#
+
+# alias %name%='echo "hello from %name%"'
+
+#
+# Functions
+#
+# Anything that needs arguments in the middle, or more than one command,
+# belongs here rather than in an alias.
+#
+
+# function %name%_hello() {
+#   echo "hello, ${1:-world}"
+# }
+
+#
+# Completion
+#
+# Oh My Zsh adds this directory to $fpath, so a file named `_sometool` next to
+# this one is picked up automatically as the completion for `sometool`.
+#
+
+#
+# Need the path to this plugin's own directory (for data files, a lib/ dir...)?
+# This is the standard way to get it, since $0 is not reliable on its own:
+# https://zdharma-continuum.github.io/Zsh-100-Commits-Club/Zsh-Plugin-Standard.html
+#
+# 0="${ZERO:-${${0:#$ZSH_ARGZERO}:-${(%):-%N}}}"
+# 0="${${(M)0:#/*}:-$PWD/$0}"
+# source "${0:A:h}/lib/helpers.zsh"

templates/generators/plugin/plugin.zsh-template

@@ -0,0 +1,43 @@
+# %name% plugin
+#
+# %description%
+#
+# This file is sourced by Oh My Zsh in every new shell, so keep it fast.
+# Avoid running external commands at the top level unless you really need to.
+
+# Only define anything if the tool is actually installed. Without this guard,
+# people who don't have %command% get aliases that fail with "command not found".
+if (( ! $+commands[%command%] )); then
+  return
+fi
+
+#
+# Aliases
+#
+# Document every alias in README.md. Short, obvious, and few beats many.
+# The one below is just an example: replace it with something %command% can do.
+#
+
+alias %command%s='%command% status'
+
+#
+# Functions
+#
+# Anything that needs arguments in the middle, or more than one command,
+# belongs here rather than in an alias.
+#
+
+# function %name%_current() {
+#   %command% status --short "$@"
+# }
+
+%completion%
+
+#
+# Need the path to this plugin's own directory (for data files, a lib/ dir...)?
+# This is the standard way to get it, since $0 is not reliable on its own:
+# https://zdharma-continuum.github.io/Zsh-100-Commits-Club/Zsh-Plugin-Standard.html
+#
+# 0="${ZERO:-${${0:#$ZSH_ARGZERO}:-${(%):-%N}}}"
+# 0="${${(M)0:#/*}:-$PWD/$0}"
+# source "${0:A:h}/lib/helpers.zsh"