From 43654cbbcc2f47acf2150d4101584bd6654241a2 Mon Sep 17 00:00:00 2001
From: Austin Blatt <austinblatt@gmail.com>
Date: Fri, 28 Jul 2017 13:53:14 -0700
Subject: [PATCH 1/2] Initial thoughts

---
 lib/tty/spinner.rb       | 5 +++++
 lib/tty/spinner/multi.rb | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/lib/tty/spinner.rb b/lib/tty/spinner.rb
index 9579973..be86c08 100644
--- a/lib/tty/spinner.rb
+++ b/lib/tty/spinner.rb
@@ -164,6 +164,11 @@ def start
     #
     # @api public
     def auto_spin
+      # TODO: this should probably be the same lock (will need to be a Monitor
+      #   rather than a Mutex) as execute_on_line, so that a spinner starts
+      #   completely before another tries to redraw itself. Also, spin needs to
+      #   run once before a spinner is fully started, so we should probably run
+      #   it once, and then start the Thread.
       SPINNER_START_LOCK.synchronize do
         start
         sleep_time = 1.0 / @interval
diff --git a/lib/tty/spinner/multi.rb b/lib/tty/spinner/multi.rb
index eff1ac2..6bf55db 100644
--- a/lib/tty/spinner/multi.rb
+++ b/lib/tty/spinner/multi.rb
@@ -36,6 +36,8 @@ def initialize(options = {})
       # @api public
       def register(pattern, options = {})
         spinner = TTY::Spinner.new(pattern, @options.merge(options))
+
+        # TODO: If two threads add a spinner at the same time, @spinners.length will be the same for both
         spinner.add_multispinner(self, @spinners.length)
         @spinners << spinner
         spinner

From 7602c94749aa2250471f1b4b494e41e341279a75 Mon Sep 17 00:00:00 2001
From: Austin Blatt <austinblatt@gmail.com>
Date: Fri, 28 Jul 2017 14:03:47 -0700
Subject: [PATCH 2/2] Attempt to fix locks

---
 lib/tty/spinner.rb       | 17 +++++++----------
 lib/tty/spinner/multi.rb | 10 +++++++---
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/lib/tty/spinner.rb b/lib/tty/spinner.rb
index be86c08..dfc46e7 100644
--- a/lib/tty/spinner.rb
+++ b/lib/tty/spinner.rb
@@ -27,6 +27,8 @@ class Spinner
     TICK = '✔'.freeze
     CROSS = '✖'.freeze
 
+    CURSOR_USAGE_LOCK = Monitor.new
+
     # The object that responds to print call defaulting to stderr
     #
     # @api public
@@ -159,20 +161,17 @@ def start
       reset
     end
 
-    SPINNER_START_LOCK = Mutex.new
     # Start automatic spinning animation
     #
     # @api public
     def auto_spin
-      # TODO: this should probably be the same lock (will need to be a Monitor
-      #   rather than a Mutex) as execute_on_line, so that a spinner starts
-      #   completely before another tries to redraw itself. Also, spin needs to
-      #   run once before a spinner is fully started, so we should probably run
-      #   it once, and then start the Thread.
-      SPINNER_START_LOCK.synchronize do
+      CURSOR_USAGE_LOCK.synchronize do
         start
         sleep_time = 1.0 / @interval
+
+        spin
         @thread = Thread.new do
+          sleep(sleep_time)
           while @started_at
             spin
             sleep(sleep_time)
@@ -344,11 +343,9 @@ def reset
 
     private
 
-    LOCK = Mutex.new
-
     def execute_on_line
       if @multispinner
-        LOCK.synchronize do
+        CURSOR_USAGE_LOCK.synchronize do
           lines_up = @multispinner.count_line_offset(@index)
 
           if @first_run
diff --git a/lib/tty/spinner/multi.rb b/lib/tty/spinner/multi.rb
index 6bf55db..0048fb7 100644
--- a/lib/tty/spinner/multi.rb
+++ b/lib/tty/spinner/multi.rb
@@ -20,6 +20,8 @@ class Multi
       def initialize(options = {})
         @options = options
 
+        @create_spinner_lock = Mutex.new
+
         @spinners = []
         @callbacks = {
           success: [],
@@ -37,9 +39,11 @@ def initialize(options = {})
       def register(pattern, options = {})
         spinner = TTY::Spinner.new(pattern, @options.merge(options))
 
-        # TODO: If two threads add a spinner at the same time, @spinners.length will be the same for both
-        spinner.add_multispinner(self, @spinners.length)
-        @spinners << spinner
+        @create_spinner_lock.synchronize do
+          spinner.add_multispinner(self, @spinners.length)
+          @spinners << spinner
+        end
+
         spinner
       end