Revert async process substitution & completion strategy

They're not quite ready. Keep them on a feature branch for now.

Makefile

@@ -1,8 +1,10 @@
 SRC_DIR    := ./src
 
 SRC_FILES := \
+	$(SRC_DIR)/setup.zsh \
 	$(SRC_DIR)/config.zsh \
 	$(SRC_DIR)/util.zsh \
+	$(SRC_DIR)/features.zsh \
 	$(SRC_DIR)/bind.zsh \
 	$(SRC_DIR)/highlight.zsh \
 	$(SRC_DIR)/widgets.zsh \

README.md

@@ -2,7 +2,7 @@
 
 _[Fish](http://fishshell.com/)-like fast/unobtrusive autosuggestions for zsh._
 
-It suggests commands as you type.
+It suggests commands as you type, based on command history.
 
 Requirements: Zsh v4.3.11 or later
 
@@ -39,13 +39,10 @@ Set `ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE` to configure the style that the suggestion
 
 ### Suggestion Strategy
 
-`ZSH_AUTOSUGGEST_STRATEGY` is an array that specifies how suggestions should be generated. The strategies in the array are tried successively until a suggestion is found. There are currently three built-in strategies to choose from:
+`ZSH_AUTOSUGGEST_STRATEGY` is an array that specifies how suggestions should be generated. The strategies in the array are tried successively until a suggestion is found. There are currently two built-in strategies to choose from:
 
 - `history`: Chooses the most recent match from history.
 - `match_prev_cmd`: Like `history`, but chooses the most recent match whose preceding history item matches the most recently executed command ([more info](src/strategies/match_prev_cmd.zsh)). Note that this strategy won't work as expected with ZSH options that don't preserve the history order such as `HIST_IGNORE_ALL_DUPS` or `HIST_EXPIRE_DUPS_FIRST`.
-- `completion`: (experimental) Chooses a suggestion based on what tab-completion would suggest. (requires `zpty` module)
-
-For example, setting `ZSH_AUTOSUGGEST_STRATEGY=(history completion)` will first try to find a suggestion from your history, but, if it can't find a match, will find a suggestion from the completion engine.
 
 
 ### Widget Mapping
@@ -70,7 +67,7 @@ This can be useful when pasting large amount of text in the terminal, to avoid t
 
 ### Enable Asynchronous Mode
 
-As of `v0.4.0`, suggestions can be fetched asynchronously. To enable this behavior, set the `ZSH_AUTOSUGGEST_USE_ASYNC` variable (it can be set to anything).
+As of `v0.4.0`, suggestions can be fetched asynchronously using the `zsh/zpty` module. To enable this behavior, set the `ZSH_AUTOSUGGEST_USE_ASYNC` variable (it can be set to anything).
 
 
 ### Key Bindings

spec/async_spec.rb

@@ -1,4 +1,8 @@
 context 'with asynchronous suggestions enabled' do
+  before do
+    skip 'Async mode not supported below v5.0.8' if session.zsh_version < Gem::Version.new('5.0.8')
+  end
+
   let(:options) { ["ZSH_AUTOSUGGEST_USE_ASYNC="] }
 
   describe '`up-line-or-beginning-search`' do
@@ -26,6 +30,55 @@ context 'with asynchronous suggestions enabled' do
       end
     end
   end
+
+  it 'should not add extra carriage returns before newlines' do
+    session.
+      send_string('echo "').
+      send_keys('escape').
+      send_keys('enter').
+      send_string('"').
+      send_keys('enter')
+
+    session.clear_screen
+
+    session.send_string('echo')
+    wait_for { session.content }.to eq("echo \"\n\"")
+  end
+
+  it 'should treat carriage returns and newlines as separate characters' do
+    session.
+      send_string('echo "').
+      send_keys('C-v').
+      send_keys('enter').
+      send_string('foo"').
+      send_keys('enter')
+
+    session.
+      send_string('echo "').
+      send_keys('control').
+      send_keys('enter').
+      send_string('bar"').
+      send_keys('enter')
+
+    session.clear_screen
+
+    session.
+      send_string('echo "').
+      send_keys('C-v').
+      send_keys('enter')
+
+    wait_for { session.content }.to eq('echo "^Mfoo"')
+  end
+
+  describe 'exiting a subshell' do
+    it 'should not cause error messages to be printed' do
+      session.run_command('$(exit)')
+
+      sleep 1
+
+      expect(session.content).to eq('$(exit)')
+    end
+  end
 end
 
 

spec/integrations/client_zpty_spec.rb

@@ -1,14 +1,10 @@
 describe 'a running zpty command' do
   let(:before_sourcing) { -> { session.run_command('zmodload zsh/zpty && zpty -b kitty cat') } }
 
-  context 'when using `completion` strategy' do
-    let(:options) { ["ZSH_AUTOSUGGEST_STRATEGY=completion"] }
-
-    it 'is not affected' do
-      session.send_keys('a').send_keys('C-h')
+  it 'is not affected by running zsh-autosuggestions' do
+    sleep 1 # Give a little time for precmd hooks to run
     session.run_command('zpty -t kitty; echo $?')
 
     wait_for { session.content }.to end_with("\n0")
   end
 end
-end

spec/options/async_zpty_name_spec.rb

@@ -0,0 +1,19 @@
+context 'when async suggestions are enabled' do
+  let(:options) { ["ZSH_AUTOSUGGEST_USE_ASYNC="] }
+
+  describe 'the zpty for async suggestions' do
+    it 'is created with the default name' do
+      session.run_command('zpty -t zsh_autosuggest_pty &>/dev/null; echo $?')
+      wait_for { session.content }.to end_with("\n0")
+    end
+
+    context 'when ZSH_AUTOSUGGEST_ASYNC_PTY_NAME is set' do
+      let(:options) { super() + ['ZSH_AUTOSUGGEST_ASYNC_PTY_NAME=foo_pty'] }
+
+      it 'is created with the specified name' do
+        session.run_command('zpty -t foo_pty &>/dev/null; echo $?')
+        wait_for { session.content }.to end_with("\n0")
+      end
+    end
+  end
+end

spec/strategies/completion_spec.rb

@@ -1,26 +0,0 @@
-describe 'the `completion` suggestion strategy' do
-  let(:options) { ['ZSH_AUTOSUGGEST_STRATEGY=completion'] }
-  let(:before_sourcing) do
-    -> do
-      session.
-        run_command('autoload compinit && compinit').
-        run_command('_foo() { compadd bar }').
-        run_command('compdef _foo baz')
-    end
-  end
-
-  it 'suggests the first completion result' do
-    session.send_string('baz ')
-    wait_for { session.content }.to eq('baz bar')
-  end
-
-  context 'when async mode is enabled' do
-    let(:options) { ['ZSH_AUTOSUGGEST_USE_ASYNC=true', 'ZSH_AUTOSUGGEST_STRATEGY=completion'] }
-
-    it 'suggests the first completion result' do
-      session.send_string('baz ')
-      wait_for { session.content }.to eq('baz bar')
-    end
-  end
-end
-

spec/terminal_session.rb

@@ -18,6 +18,10 @@ class TerminalSession
     tmux_command("new-session -d -x #{opts[:width]} -y #{opts[:height]} '#{cmd}'")
   end
 
+  def zsh_version
+    @zsh_version ||= Gem::Version.new(`#{ZSH_BIN} -c 'echo -n $ZSH_VERSION'`)
+  end
+
   def tmux_socket_name
     @tmux_socket_name ||= SecureRandom.hex(6)
   end

src/async.zsh

@@ -3,61 +3,107 @@
 # Async                                                              #
 #--------------------------------------------------------------------#
 
-zmodload zsh/system
+# Zpty process is spawned running this function
+_zsh_autosuggest_async_server() {
+	emulate -R zsh
 
-_zsh_autosuggest_async_request() {
-	typeset -g _ZSH_AUTOSUGGEST_ASYNC_FD _ZSH_AUTOSUGGEST_CHILD_PID
-
-	# If we've got a pending request, cancel it
-	if [[ -n "$_ZSH_AUTOSUGGEST_ASYNC_FD" ]] && { true <&$_ZSH_AUTOSUGGEST_ASYNC_FD } 2>/dev/null; then
-		# Close the file descriptor and remove the handler
-		exec {_ZSH_AUTOSUGGEST_ASYNC_FD}<&-
-		zle -F $_ZSH_AUTOSUGGEST_ASYNC_FD
-
-		# Zsh will make a new process group for the child process only if job
-		# control is enabled (MONITOR option)
-		if [[ -o MONITOR ]]; then
-			# Send the signal to the process group to kill any processes that may
-			# have been forked by the suggestion strategy
-			kill -TERM -$_ZSH_AUTOSUGGEST_CHILD_PID 2>/dev/null
-		else
-			# Kill just the child process since it wasn't placed in a new process
-			# group. If the suggestion strategy forked any child processes they may
-			# be orphaned and left behind.
-			kill -TERM $_ZSH_AUTOSUGGEST_CHILD_PID 2>/dev/null
-		fi
-	fi
-
-	# Fork a process to fetch a suggestion and open a pipe to read from it
-	exec {_ZSH_AUTOSUGGEST_ASYNC_FD}< <(
-		# Tell parent process our pid
-		echo $sysparams[pid]
-
-		# Fetch and print the suggestion
-		local suggestion
-		_zsh_autosuggest_fetch_suggestion "$1"
-		echo -nE "$suggestion"
-	)
-
-	# Read the pid from the child process
-	read _ZSH_AUTOSUGGEST_CHILD_PID <&$_ZSH_AUTOSUGGEST_ASYNC_FD
-
-	# When the fd is readable, call the response handler
-	zle -F "$_ZSH_AUTOSUGGEST_ASYNC_FD" _zsh_autosuggest_async_response
+	# There is a bug in zpty module (fixed in zsh/master) by which a
+	# zpty that exits will kill all zpty processes that were forked
+	# before it. Here we set up a zsh exit hook to SIGKILL the zpty
+	# process immediately, before it has a chance to kill any other
+	# zpty processes.
+	zshexit() {
+		kill -KILL $$
+		sleep 1 # Block for long enough for the signal to come through
 	}
 
-# Called when new data is ready to be read from the pipe
+	# Don't add any extra carriage returns
+	stty -onlcr
+
+	# Don't translate carriage returns to newlines
+	stty -icrnl
+
+	# Silence any error messages
+	exec 2>/dev/null
+
+	local last_pid
+
+	while IFS='' read -r -d $'\0' query; do
+		# Kill last bg process
+		kill -KILL $last_pid &>/dev/null
+
+		# Run suggestion search in the background
+		(
+			local suggestion
+			_zsh_autosuggest_fetch_suggestion "$query"
+			echo -n -E "$suggestion"$'\0'
+		) &
+
+		last_pid=$!
+	done
+}
+
+_zsh_autosuggest_async_request() {
+	# Write the query to the zpty process to fetch a suggestion
+	zpty -w -n $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME "${1}"$'\0'
+}
+
+# Called when new data is ready to be read from the pty
 # First arg will be fd ready for reading
 # Second arg will be passed in case of error
 _zsh_autosuggest_async_response() {
-	if [[ -z "$2" || "$2" == "hup" ]]; then
-		# Read everything from the fd and give it as a suggestion
-		zle autosuggest-suggest -- "$(cat <&$1)"
+	setopt LOCAL_OPTIONS EXTENDED_GLOB
 
-		# Close the fd
-		exec {1}<&-
+	local suggestion
+
+	zpty -rt $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME suggestion '*'$'\0' 2>/dev/null
+	zle autosuggest-suggest -- "${suggestion%%$'\0'##}"
+}
+
+_zsh_autosuggest_async_pty_create() {
+	# With newer versions of zsh, REPLY stores the fd to read from
+	typeset -h REPLY
+
+	# If we won't get a fd back from zpty, try to guess it
+	if (( ! $_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD )); then
+		integer -l zptyfd
+		exec {zptyfd}>&1  # Open a new file descriptor (above 10).
+		exec {zptyfd}>&-  # Close it so it's free to be used by zpty.
 	fi
 
-	# Always remove the handler
-	zle -F "$1"
+	# Fork a zpty process running the server function
+	zpty -b $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME _zsh_autosuggest_async_server
+
+	# Store the fd so we can remove the handler later
+	if (( REPLY )); then
+		_ZSH_AUTOSUGGEST_PTY_FD=$REPLY
+	else
+		_ZSH_AUTOSUGGEST_PTY_FD=$zptyfd
+	fi
+
+	# Set up input handler from the zpty
+	zle -F $_ZSH_AUTOSUGGEST_PTY_FD _zsh_autosuggest_async_response
+}
+
+_zsh_autosuggest_async_pty_destroy() {
+	# Remove the input handler
+	zle -F $_ZSH_AUTOSUGGEST_PTY_FD &>/dev/null
+
+	# Destroy the zpty
+	zpty -d $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME &>/dev/null
+}
+
+_zsh_autosuggest_async_pty_recreate() {
+	_zsh_autosuggest_async_pty_destroy
+	_zsh_autosuggest_async_pty_create
+}
+
+_zsh_autosuggest_async_start() {
+	typeset -g _ZSH_AUTOSUGGEST_PTY_FD
+
+	_zsh_autosuggest_feature_detect_zpty_returns_fd
+	_zsh_autosuggest_async_pty_recreate
+
+	# We recreate the pty to get a fresh list of history events
+	add-zsh-hook precmd _zsh_autosuggest_async_pty_recreate
 }

src/config.zsh

@@ -69,5 +69,5 @@
 # Max size of buffer to trigger autosuggestion. Leave null for no upper bound.
 : ${ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE=}
 
-# Pty name for capturing completions for completion suggestion strategy
-: ${ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME=zsh_autosuggest_completion_pty}
+# Pty name for calculating autosuggestions asynchronously
+: ${ZSH_AUTOSUGGEST_ASYNC_PTY_NAME=zsh_autosuggest_pty}

src/features.zsh

@@ -0,0 +1,19 @@
+
+#--------------------------------------------------------------------#
+# Feature Detection                                                  #
+#--------------------------------------------------------------------#
+
+_zsh_autosuggest_feature_detect_zpty_returns_fd() {
+	typeset -g _ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD
+	typeset -h REPLY
+
+	zpty zsh_autosuggest_feature_detect '{ zshexit() { kill -KILL $$; sleep 1 } }'
+
+	if (( REPLY )); then
+		_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD=1
+	else
+		_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD=0
+	fi
+
+	zpty -d zsh_autosuggest_feature_detect
+}

src/setup.zsh

@@ -0,0 +1,10 @@
+
+#--------------------------------------------------------------------#
+# Setup                                                              #
+#--------------------------------------------------------------------#
+
+# Precmd hooks for initializing the library and starting pty's
+autoload -Uz add-zsh-hook
+
+# Asynchronous suggestions are generated in a pty
+zmodload zsh/zpty

src/start.zsh

@@ -14,8 +14,11 @@ _zsh_autosuggest_start() {
 	# zsh-syntax-highlighting widgets. This also allows modifications
 	# to the widget list variables to take effect on the next precmd.
 	add-zsh-hook precmd _zsh_autosuggest_bind_widgets
+
+	if [[ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]]; then
+		_zsh_autosuggest_async_start
+	fi
 }
 
 # Start the autosuggestion widgets on the next precmd
-autoload -Uz add-zsh-hook
 add-zsh-hook precmd _zsh_autosuggest_start

src/strategies/completion.zsh

@@ -1,104 +0,0 @@
-
-#--------------------------------------------------------------------#
-# Completion Suggestion Strategy                                     #
-#--------------------------------------------------------------------#
-# Fetches a suggestion from the completion engine
-#
-
-_zsh_autosuggest_capture_postcompletion() {
-	# Always insert the first completion into the buffer
-	compstate[insert]=1
-
-	# Don't list completions
-	unset compstate[list]
-}
-
-_zsh_autosuggest_capture_completion_widget() {
-	local -a +h comppostfuncs
-	comppostfuncs=(_zsh_autosuggest_capture_postcompletion)
-
-	# Only capture completions at the end of the buffer
-	CURSOR=$#BUFFER
-
-	# Run the original widget wrapping `.complete-word` so we don't
-	# recursively try to fetch suggestions, since our pty is forked
-	# after autosuggestions is initialized.
-	zle -- ${(k)widgets[(r)completion:.complete-word:_main_complete]}
-
-	# The completion has been added, print the buffer as the suggestion
-	echo -nE - $'\0'$BUFFER$'\0'
-}
-
-zle -N autosuggest-capture-completion _zsh_autosuggest_capture_completion_widget
-
-_zsh_autosuggest_capture_setup() {
-	# There is a bug in zpty module in older zsh versions by which a
-	# zpty that exits will kill all zpty processes that were forked
-	# before it. Here we set up a zsh exit hook to SIGKILL the zpty
-	# process immediately, before it has a chance to kill any other
-	# zpty processes.
-	if ! is-at-least 5.4; then
-		zshexit() {
-			kill -KILL $$
-			sleep 1 # Block for long enough for the signal to come through
-		}
-	fi
-
-	bindkey '^I' autosuggest-capture-completion
-}
-
-_zsh_autosuggest_capture_completion_sync() {
-	_zsh_autosuggest_capture_setup
-
-	zle autosuggest-capture-completion
-}
-
-_zsh_autosuggest_capture_completion_async() {
-	_zsh_autosuggest_capture_setup
-
-	zmodload zsh/parameter 2>/dev/null || return # For `$functions`
-
-	# Make vared completion work as if for a normal command line
-	# https://stackoverflow.com/a/7057118/154703
-	autoload +X _complete
-	functions[_original_complete]=$functions[_complete]
-	_complete () {
-		unset 'compstate[vared]'
-		_original_complete "$@"
-	}
-
-	# Open zle with buffer set so we can capture completions for it
-	vared 1
-}
-
-_zsh_autosuggest_strategy_completion() {
-	typeset -g suggestion
-	local line REPLY
-
-	# Exit if we don't have completions
-	whence compdef >/dev/null || return
-
-	# Exit if we don't have zpty
-	zmodload zsh/zpty 2>/dev/null || return
-
-	# Zle will be inactive if we are in async mode
-	if zle; then
-		zpty $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME _zsh_autosuggest_capture_completion_sync
-	else
-		zpty $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME _zsh_autosuggest_capture_completion_async "\$1"
-		zpty -w $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME $'\t'
-	fi
-
-	{
-		# The completion result is surrounded by null bytes, so read the
-		# content between the first two null bytes.
-		zpty -r $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME line '*'$'\0''*'$'\0'
-
-		# On older versions of zsh, we sometimes get extra bytes after the
-		# second null byte, so trim those off the end
-		suggestion="${${${(M)line:#*$'\0'*$'\0'*}#*$'\0'}%%$'\0'*}"
-	} always {
-		# Destroy the pty
-		zpty -d $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME
-	}
-}

src/widgets.zsh

@@ -95,7 +95,7 @@ _zsh_autosuggest_modify() {
 
 # Fetch a new suggestion based on what's currently in the buffer
 _zsh_autosuggest_fetch() {
-	if [[ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]]; then
+	if zpty -t "$ZSH_AUTOSUGGEST_ASYNC_PTY_NAME" &>/dev/null; then
 		_zsh_autosuggest_async_request "$BUFFER"
 	else
 		local suggestion

zsh-autosuggestions.zsh

@@ -25,6 +25,16 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 # OTHER DEALINGS IN THE SOFTWARE.
 
+#--------------------------------------------------------------------#
+# Setup                                                              #
+#--------------------------------------------------------------------#
+
+# Precmd hooks for initializing the library and starting pty's
+autoload -Uz add-zsh-hook
+
+# Asynchronous suggestions are generated in a pty
+zmodload zsh/zpty
+
 #--------------------------------------------------------------------#
 # Global Configuration Variables                                     #
 #--------------------------------------------------------------------#
@@ -95,8 +105,8 @@
 # Max size of buffer to trigger autosuggestion. Leave null for no upper bound.
 : ${ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE=}
 
-# Pty name for capturing completions for completion suggestion strategy
-: ${ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME=zsh_autosuggest_completion_pty}
+# Pty name for calculating autosuggestions asynchronously
+: ${ZSH_AUTOSUGGEST_ASYNC_PTY_NAME=zsh_autosuggest_pty}
 
 #--------------------------------------------------------------------#
 # Utility Functions                                                  #
@@ -109,6 +119,25 @@ _zsh_autosuggest_escape_command() {
 	echo -E "${1//(#m)[\"\'\\()\[\]|*?~]/\\$MATCH}"
 }
 
+#--------------------------------------------------------------------#
+# Feature Detection                                                  #
+#--------------------------------------------------------------------#
+
+_zsh_autosuggest_feature_detect_zpty_returns_fd() {
+	typeset -g _ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD
+	typeset -h REPLY
+
+	zpty zsh_autosuggest_feature_detect '{ zshexit() { kill -KILL $$; sleep 1 } }'
+
+	if (( REPLY )); then
+		_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD=1
+	else
+		_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD=0
+	fi
+
+	zpty -d zsh_autosuggest_feature_detect
+}
+
 #--------------------------------------------------------------------#
 # Widget Helpers                                                     #
 #--------------------------------------------------------------------#
@@ -351,7 +380,7 @@ _zsh_autosuggest_modify() {
 
 # Fetch a new suggestion based on what's currently in the buffer
 _zsh_autosuggest_fetch() {
-	if [[ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]]; then
+	if zpty -t "$ZSH_AUTOSUGGEST_ASYNC_PTY_NAME" &>/dev/null; then
 		_zsh_autosuggest_async_request "$BUFFER"
 	else
 		local suggestion
@@ -472,110 +501,6 @@ zle -N autosuggest-enable _zsh_autosuggest_widget_enable
 zle -N autosuggest-disable _zsh_autosuggest_widget_disable
 zle -N autosuggest-toggle _zsh_autosuggest_widget_toggle
 
-#--------------------------------------------------------------------#
-# Completion Suggestion Strategy                                     #
-#--------------------------------------------------------------------#
-# Fetches a suggestion from the completion engine
-#
-
-_zsh_autosuggest_capture_postcompletion() {
-	# Always insert the first completion into the buffer
-	compstate[insert]=1
-
-	# Don't list completions
-	unset compstate[list]
-}
-
-_zsh_autosuggest_capture_completion_widget() {
-	local -a +h comppostfuncs
-	comppostfuncs=(_zsh_autosuggest_capture_postcompletion)
-
-	# Only capture completions at the end of the buffer
-	CURSOR=$#BUFFER
-
-	# Run the original widget wrapping `.complete-word` so we don't
-	# recursively try to fetch suggestions, since our pty is forked
-	# after autosuggestions is initialized.
-	zle -- ${(k)widgets[(r)completion:.complete-word:_main_complete]}
-
-	# The completion has been added, print the buffer as the suggestion
-	echo -nE - $'\0'$BUFFER$'\0'
-}
-
-zle -N autosuggest-capture-completion _zsh_autosuggest_capture_completion_widget
-
-_zsh_autosuggest_capture_setup() {
-	# There is a bug in zpty module in older zsh versions by which a
-	# zpty that exits will kill all zpty processes that were forked
-	# before it. Here we set up a zsh exit hook to SIGKILL the zpty
-	# process immediately, before it has a chance to kill any other
-	# zpty processes.
-	if ! is-at-least 5.4; then
-		zshexit() {
-			kill -KILL $$
-			sleep 1 # Block for long enough for the signal to come through
-		}
-	fi
-
-	bindkey '^I' autosuggest-capture-completion
-}
-
-_zsh_autosuggest_capture_completion_sync() {
-	_zsh_autosuggest_capture_setup
-
-	zle autosuggest-capture-completion
-}
-
-_zsh_autosuggest_capture_completion_async() {
-	_zsh_autosuggest_capture_setup
-
-	zmodload zsh/parameter 2>/dev/null || return # For `$functions`
-
-	# Make vared completion work as if for a normal command line
-	# https://stackoverflow.com/a/7057118/154703
-	autoload +X _complete
-	functions[_original_complete]=$functions[_complete]
-	_complete () {
-		unset 'compstate[vared]'
-		_original_complete "$@"
-	}
-
-	# Open zle with buffer set so we can capture completions for it
-	vared 1
-}
-
-_zsh_autosuggest_strategy_completion() {
-	typeset -g suggestion
-	local line REPLY
-
-	# Exit if we don't have completions
-	whence compdef >/dev/null || return
-
-	# Exit if we don't have zpty
-	zmodload zsh/zpty 2>/dev/null || return
-
-	# Zle will be inactive if we are in async mode
-	if zle; then
-		zpty $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME _zsh_autosuggest_capture_completion_sync
-	else
-		zpty $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME _zsh_autosuggest_capture_completion_async "\$1"
-		zpty -w $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME $'\t'
-	fi
-
-	{
-		# The completion result is surrounded by null bytes, so read the
-		# content between the first two null bytes.
-		zpty -r $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME line '*'$'\0''*'$'\0'
-
-		# On older versions of zsh, we sometimes get extra bytes after the
-		# second null byte, so trim those off the end
-		suggestion="${${${(M)line:#*$'\0'*$'\0'*}#*$'\0'}%%$'\0'*}"
-	} always {
-		# Destroy the pty
-		zpty -d $ZSH_AUTOSUGGEST_COMPLETIONS_PTY_NAME
-	}
-}
-
 #--------------------------------------------------------------------#
 # History Suggestion Strategy                                        #
 #--------------------------------------------------------------------#
@@ -688,63 +613,109 @@ _zsh_autosuggest_fetch_suggestion() {
 # Async                                                              #
 #--------------------------------------------------------------------#
 
-zmodload zsh/system
+# Zpty process is spawned running this function
+_zsh_autosuggest_async_server() {
+	emulate -R zsh
 
-_zsh_autosuggest_async_request() {
-	typeset -g _ZSH_AUTOSUGGEST_ASYNC_FD _ZSH_AUTOSUGGEST_CHILD_PID
-
-	# If we've got a pending request, cancel it
-	if [[ -n "$_ZSH_AUTOSUGGEST_ASYNC_FD" ]] && { true <&$_ZSH_AUTOSUGGEST_ASYNC_FD } 2>/dev/null; then
-		# Close the file descriptor and remove the handler
-		exec {_ZSH_AUTOSUGGEST_ASYNC_FD}<&-
-		zle -F $_ZSH_AUTOSUGGEST_ASYNC_FD
-
-		# Zsh will make a new process group for the child process only if job
-		# control is enabled (MONITOR option)
-		if [[ -o MONITOR ]]; then
-			# Send the signal to the process group to kill any processes that may
-			# have been forked by the suggestion strategy
-			kill -TERM -$_ZSH_AUTOSUGGEST_CHILD_PID 2>/dev/null
-		else
-			# Kill just the child process since it wasn't placed in a new process
-			# group. If the suggestion strategy forked any child processes they may
-			# be orphaned and left behind.
-			kill -TERM $_ZSH_AUTOSUGGEST_CHILD_PID 2>/dev/null
-		fi
-	fi
-
-	# Fork a process to fetch a suggestion and open a pipe to read from it
-	exec {_ZSH_AUTOSUGGEST_ASYNC_FD}< <(
-		# Tell parent process our pid
-		echo $sysparams[pid]
-
-		# Fetch and print the suggestion
-		local suggestion
-		_zsh_autosuggest_fetch_suggestion "$1"
-		echo -nE "$suggestion"
-	)
-
-	# Read the pid from the child process
-	read _ZSH_AUTOSUGGEST_CHILD_PID <&$_ZSH_AUTOSUGGEST_ASYNC_FD
-
-	# When the fd is readable, call the response handler
-	zle -F "$_ZSH_AUTOSUGGEST_ASYNC_FD" _zsh_autosuggest_async_response
+	# There is a bug in zpty module (fixed in zsh/master) by which a
+	# zpty that exits will kill all zpty processes that were forked
+	# before it. Here we set up a zsh exit hook to SIGKILL the zpty
+	# process immediately, before it has a chance to kill any other
+	# zpty processes.
+	zshexit() {
+		kill -KILL $$
+		sleep 1 # Block for long enough for the signal to come through
 	}
 
-# Called when new data is ready to be read from the pipe
+	# Don't add any extra carriage returns
+	stty -onlcr
+
+	# Don't translate carriage returns to newlines
+	stty -icrnl
+
+	# Silence any error messages
+	exec 2>/dev/null
+
+	local last_pid
+
+	while IFS='' read -r -d $'\0' query; do
+		# Kill last bg process
+		kill -KILL $last_pid &>/dev/null
+
+		# Run suggestion search in the background
+		(
+			local suggestion
+			_zsh_autosuggest_fetch_suggestion "$query"
+			echo -n -E "$suggestion"$'\0'
+		) &
+
+		last_pid=$!
+	done
+}
+
+_zsh_autosuggest_async_request() {
+	# Write the query to the zpty process to fetch a suggestion
+	zpty -w -n $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME "${1}"$'\0'
+}
+
+# Called when new data is ready to be read from the pty
 # First arg will be fd ready for reading
 # Second arg will be passed in case of error
 _zsh_autosuggest_async_response() {
-	if [[ -z "$2" || "$2" == "hup" ]]; then
-		# Read everything from the fd and give it as a suggestion
-		zle autosuggest-suggest -- "$(cat <&$1)"
+	setopt LOCAL_OPTIONS EXTENDED_GLOB
 
-		# Close the fd
-		exec {1}<&-
+	local suggestion
+
+	zpty -rt $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME suggestion '*'$'\0' 2>/dev/null
+	zle autosuggest-suggest -- "${suggestion%%$'\0'##}"
+}
+
+_zsh_autosuggest_async_pty_create() {
+	# With newer versions of zsh, REPLY stores the fd to read from
+	typeset -h REPLY
+
+	# If we won't get a fd back from zpty, try to guess it
+	if (( ! $_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD )); then
+		integer -l zptyfd
+		exec {zptyfd}>&1  # Open a new file descriptor (above 10).
+		exec {zptyfd}>&-  # Close it so it's free to be used by zpty.
 	fi
 
-	# Always remove the handler
-	zle -F "$1"
+	# Fork a zpty process running the server function
+	zpty -b $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME _zsh_autosuggest_async_server
+
+	# Store the fd so we can remove the handler later
+	if (( REPLY )); then
+		_ZSH_AUTOSUGGEST_PTY_FD=$REPLY
+	else
+		_ZSH_AUTOSUGGEST_PTY_FD=$zptyfd
+	fi
+
+	# Set up input handler from the zpty
+	zle -F $_ZSH_AUTOSUGGEST_PTY_FD _zsh_autosuggest_async_response
+}
+
+_zsh_autosuggest_async_pty_destroy() {
+	# Remove the input handler
+	zle -F $_ZSH_AUTOSUGGEST_PTY_FD &>/dev/null
+
+	# Destroy the zpty
+	zpty -d $ZSH_AUTOSUGGEST_ASYNC_PTY_NAME &>/dev/null
+}
+
+_zsh_autosuggest_async_pty_recreate() {
+	_zsh_autosuggest_async_pty_destroy
+	_zsh_autosuggest_async_pty_create
+}
+
+_zsh_autosuggest_async_start() {
+	typeset -g _ZSH_AUTOSUGGEST_PTY_FD
+
+	_zsh_autosuggest_feature_detect_zpty_returns_fd
+	_zsh_autosuggest_async_pty_recreate
+
+	# We recreate the pty to get a fresh list of history events
+	add-zsh-hook precmd _zsh_autosuggest_async_pty_recreate
 }
 
 #--------------------------------------------------------------------#
@@ -762,8 +733,11 @@ _zsh_autosuggest_start() {
 	# zsh-syntax-highlighting widgets. This also allows modifications
 	# to the widget list variables to take effect on the next precmd.
 	add-zsh-hook precmd _zsh_autosuggest_bind_widgets
+
+	if [[ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]]; then
+		_zsh_autosuggest_async_start
+	fi
 }
 
 # Start the autosuggestion widgets on the next precmd
-autoload -Uz add-zsh-hook
 add-zsh-hook precmd _zsh_autosuggest_start