Fix issue where partial accept duplicates last word

When z-sy-h is enabled after autosuggestion widgets have already been
bound, partial accepting the last part of a suggestion will result in
that string being duplicated.

I was able to reproduce using the following versions of the two plugins:
- z-sy-h: dde84e1b25f059a298ce3189cddfd0778f998df3
- z-asug: ae315ded4d

and running the following commands interactively one after another:

```
zsh -df
% source path/to/zsh-autosuggestions.zsh
% source path/to/zsh-syntax-highlighting.zsh
% bindkey -e
% bindkey <alt-f>         # shows 'bindkey -e-e'
```

The order of the `source` statements matters and the issue cannot be
reproduced if the two source statements are executed together on one
line.

The problem is very similar to this one:
  https://github.com/zsh-users/zsh-autosuggestions/issues/126#issuecomment-217121315

See GitHub issue #483

CHANGELOG.md

@@ -1,11 +1,5 @@
 # Changelog
 
-## v0.7.0
-- Enable asynchronous mode by default (#498)
-- No longer wrap user widgets starting with `autosuggest-` prefix (#496)
-- Fix a bug wrapping widgets that modify the buffer (#541)
-
-
 ## v0.6.4
 - Fix `vi-forward-char` triggering a bell when using it to accept a suggestion (#488)
 - New configuration option to skip completion suggestions when buffer matches a pattern (#487)

INSTALL.md

@@ -39,10 +39,7 @@
 2. Add the plugin to the list of plugins for Oh My Zsh to load (inside `~/.zshrc`):
 
     ```sh
-    plugins=( 
+    plugins=(zsh-autosuggestions)
-        # other plugins...
-        zsh-autosuggestions
-    )
     ```
 
 3. Start a new terminal session.

LICENSE

@@ -1,5 +1,5 @@
 Copyright (c) 2013 Thiago de Arruda
-Copyright (c) 2016-2021 Eric Freese
+Copyright (c) 2016-2019 Eric Freese
 
 Permission is hereby granted, free of charge, to any person
 obtaining a copy of this software and associated documentation

VERSION

@@ -1 +1 @@
-v0.7.0
+v0.6.4

ZSH_VERSIONS

@@ -14,4 +14,3 @@
 5.5.1
 5.6.2
 5.7.1
-5.8

spec/multi_line_spec.rb

@@ -1,6 +1,11 @@
 describe 'a multi-line suggestion' do
   it 'should be displayed on multiple lines' do
-    with_history("echo \"\n\"") do
+    with_history(-> {
+      session.send_string('echo "')
+      session.send_keys('enter')
+      session.send_string('"')
+      session.send_keys('enter')
+    }) do
       session.send_keys('e')
       wait_for { session.content }.to eq("echo \"\n\"")
     end

spec/spec_helper.rb

@@ -1,7 +1,6 @@
 require 'pry'
 require 'rspec/wait'
 require 'terminal_session'
-require 'tempfile'
 
 RSpec.shared_context 'terminal session' do
   let(:term_opts) { {} }
@@ -22,12 +21,11 @@ RSpec.shared_context 'terminal session' do
   end
 
   def with_history(*commands, &block)
-    Tempfile.create do |f|
-      f.write(commands.map{|c| c.gsub("\n", "\\\n")}.join("\n"))
-      f.flush
-
     session.run_command('fc -p')
-      session.run_command("fc -R #{f.path}")
+
+    commands.each do |c|
+      c.respond_to?(:call) ? c.call : session.run_command(c)
+    end
 
     session.clear_screen
 
@@ -37,7 +35,6 @@ RSpec.shared_context 'terminal session' do
     session.run_command('fc -P')
   end
 end
-end
 
 RSpec.configure do |config|
   config.expect_with :rspec do |expectations|

spec/strategies/special_characters_helper.rb

@@ -1,71 +1,58 @@
 shared_examples 'special characters' do
-  describe 'a special character in the buffer should be treated like any other character' do
+  describe 'a special character in the buffer' do
-    it 'asterisk' do
+    it 'should be treated like any other character' do
       with_history('echo "hello*"', 'echo "hello."') do
         session.send_string('echo "hello*')
         wait_for { session.content }.to eq('echo "hello*"')
       end
-    end
 
-    it 'question mark' do
       with_history('echo "hello?"', 'echo "hello."') do
         session.send_string('echo "hello?')
         wait_for { session.content }.to eq('echo "hello?"')
       end
-    end
 
-    it 'backslash' do
       with_history('echo "hello\nworld"') do
         session.send_string('echo "hello\\')
         wait_for { session.content }.to eq('echo "hello\nworld"')
       end
-    end
 
-    it 'double backslash' do
       with_history('echo "\\\\"') do
         session.send_string('echo "\\\\')
         wait_for { session.content }.to eq('echo "\\\\"')
       end
-    end
 
-    it 'tilde' do
       with_history('echo ~/foo') do
         session.send_string('echo ~')
         wait_for { session.content }.to eq('echo ~/foo')
       end
-    end
 
-    it 'parentheses' do
       with_history('echo "$(ls foo)"') do
         session.send_string('echo "$(')
         wait_for { session.content }.to eq('echo "$(ls foo)"')
       end
-    end
 
-    it 'square bracket' do
       with_history('echo "$history[123]"') do
         session.send_string('echo "$history[')
         wait_for { session.content }.to eq('echo "$history[123]"')
         session.send_string('123]')
         wait_for { session.content }.to eq('echo "$history[123]"')
       end
-    end
 
-    it 'octothorpe' do
       with_history('echo "#yolo"') do
         session.send_string('echo "#')
         wait_for { session.content }.to eq('echo "#yolo"')
       end
+
+      with_history('echo "#foo"', 'echo $#abc') do
+        session.send_string('echo "#')
+        wait_for { session.content }.to eq('echo "#foo"')
       end
 
-    it 'caret' do
       with_history('echo "^A"', 'echo "^B"') do
         session.send_string('echo "^A')
         wait_for { session.content }.to eq('echo "^A"')
       end
-    end
 
-    it 'dash' do
       with_history('-foo() {}') do
         session.send_string('-')
         wait_for { session.content }.to eq('-foo() {}')

src/async.zsh

@@ -44,8 +44,7 @@ _zsh_autosuggest_async_request() {
 
 	# There's a weird bug here where ^C stops working unless we force a fork
 	# See https://github.com/zsh-users/zsh-autosuggestions/issues/364
-	autoload -Uz is-at-least
+	command true
-	is-at-least 5.8 || command true
 
 	# Read the pid from the child process
 	read _ZSH_AUTOSUGGEST_CHILD_PID <&$_ZSH_AUTOSUGGEST_ASYNC_FD

src/widgets.zsh

@@ -61,9 +61,20 @@ _zsh_autosuggest_modify() {
 		return $retval
 	fi
 
-	# Optimize if manually typing in the suggestion or if buffer hasn't changed
+	# Optimize if manually typing in the suggestion
-	if [[ "$BUFFER" = "$orig_buffer"* && "$orig_postdisplay" = "${BUFFER:$#orig_buffer}"* ]]; then
+	if (( $#BUFFER > $#orig_buffer )); then
-		POSTDISPLAY="${orig_postdisplay:$(($#BUFFER - $#orig_buffer))}"
+		local added=${BUFFER#$orig_buffer}
+
+		# If the string added matches the beginning of the postdisplay
+		if [[ "$added" = "${orig_postdisplay:0:$#added}" ]]; then
+			POSTDISPLAY="${orig_postdisplay:$#added}"
+			return $retval
+		fi
+	fi
+
+	# Don't fetch a new suggestion if the buffer hasn't changed
+	if [[ "$BUFFER" = "$orig_buffer" ]]; then
+		POSTDISPLAY="$orig_postdisplay"
 		return $retval
 	fi
 
@@ -162,11 +173,13 @@ _zsh_autosuggest_execute() {
 _zsh_autosuggest_partial_accept() {
 	local -i retval cursor_loc
 
-	# Save the contents of the buffer so we can restore later if needed
+	# Save the original buffer/postdisplay so we can restore later if needed
 	local original_buffer="$BUFFER"
+	local original_postdisplay="$POSTDISPLAY"
 
 	# Temporarily accept the suggestion.
 	BUFFER="$BUFFER$POSTDISPLAY"
+	unset POSTDISPLAY
 
 	# Original widget moves the cursor
 	_zsh_autosuggest_invoke_original_widget $@
@@ -186,8 +199,9 @@ _zsh_autosuggest_partial_accept() {
 		# Clip the buffer at the cursor
 		BUFFER="${BUFFER[1,$cursor_loc]}"
 	else
-		# Restore the original buffer
+		# Restore the original buffer/postdisplay
 		BUFFER="$original_buffer"
+		POSTDISPLAY="$original_postdisplay"
 	fi
 
 	return $retval

zsh-autosuggestions.zsh

@@ -1,8 +1,8 @@
 # Fish-like fast/unobtrusive autosuggestions for zsh.
 # https://github.com/zsh-users/zsh-autosuggestions
-# v0.7.0
+# v0.6.4
 # Copyright (c) 2013 Thiago de Arruda
-# Copyright (c) 2016-2021 Eric Freese
+# Copyright (c) 2016-2019 Eric Freese
 # 
 # Permission is hereby granted, free of charge, to any person
 # obtaining a copy of this software and associated documentation
@@ -323,9 +323,20 @@ _zsh_autosuggest_modify() {
 		return $retval
 	fi
 
-	# Optimize if manually typing in the suggestion or if buffer hasn't changed
+	# Optimize if manually typing in the suggestion
-	if [[ "$BUFFER" = "$orig_buffer"* && "$orig_postdisplay" = "${BUFFER:$#orig_buffer}"* ]]; then
+	if (( $#BUFFER > $#orig_buffer )); then
-		POSTDISPLAY="${orig_postdisplay:$(($#BUFFER - $#orig_buffer))}"
+		local added=${BUFFER#$orig_buffer}
+
+		# If the string added matches the beginning of the postdisplay
+		if [[ "$added" = "${orig_postdisplay:0:$#added}" ]]; then
+			POSTDISPLAY="${orig_postdisplay:$#added}"
+			return $retval
+		fi
+	fi
+
+	# Don't fetch a new suggestion if the buffer hasn't changed
+	if [[ "$BUFFER" = "$orig_buffer" ]]; then
+		POSTDISPLAY="$orig_postdisplay"
 		return $retval
 	fi
 
@@ -424,11 +435,13 @@ _zsh_autosuggest_execute() {
 _zsh_autosuggest_partial_accept() {
 	local -i retval cursor_loc
 
-	# Save the contents of the buffer so we can restore later if needed
+	# Save the original buffer/postdisplay so we can restore later if needed
 	local original_buffer="$BUFFER"
+	local original_postdisplay="$POSTDISPLAY"
 
 	# Temporarily accept the suggestion.
 	BUFFER="$BUFFER$POSTDISPLAY"
+	unset POSTDISPLAY
 
 	# Original widget moves the cursor
 	_zsh_autosuggest_invoke_original_widget $@
@@ -448,8 +461,9 @@ _zsh_autosuggest_partial_accept() {
 		# Clip the buffer at the cursor
 		BUFFER="${BUFFER[1,$cursor_loc]}"
 	else
-		# Restore the original buffer
+		# Restore the original buffer/postdisplay
 		BUFFER="$original_buffer"
+		POSTDISPLAY="$original_postdisplay"
 	fi
 
 	return $retval
@@ -799,8 +813,7 @@ _zsh_autosuggest_async_request() {
 
 	# There's a weird bug here where ^C stops working unless we force a fork
 	# See https://github.com/zsh-users/zsh-autosuggestions/issues/364
-	autoload -Uz is-at-least
+	command true
-	is-at-least 5.8 || command true
 
 	# Read the pid from the child process
 	read _ZSH_AUTOSUGGEST_CHILD_PID <&$_ZSH_AUTOSUGGEST_ASYNC_FD