From 415a0596bbdefec83c9423de464e846e651b3a0b Mon Sep 17 00:00:00 2001
From: Sam Atman <atmanistan@gmail.com>
Date: Sat, 26 Mar 2022 09:19:36 -0400
Subject: [PATCH 1/2] Adds string conversion, caches 'coroutine' by tag

This patch makes two changes: it caches the return values by tag, and auto-converts a string tag into a private table.

The combination of these means that any module can call something like

```lua
local coro = coromake 'scheduler'
```
And will obtain the same nested coroutines table, without running into a problem with using `yield 'scheduler'` somewhere as a literal value.

Which is visible in the example, but the silent bug is when the string slips into some process or collection.
---
 src/coroutine/make.lua | 39 ++++++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/src/coroutine/make.lua b/src/coroutine/make.lua
index 66d7adb..e94eb68 100644
--- a/src/coroutine/make.lua
+++ b/src/coroutine/make.lua
@@ -1,20 +1,37 @@
-local select      = select
-local create      = coroutine.create
-local isyieldable = coroutine.isyieldable -- luacheck: ignore
-local resume      = coroutine.resume
-local running     = coroutine.running
-local status      = coroutine.status
-local wrap        = coroutine.wrap
-local yield       = coroutine.yield
-
-return function (tag)
+local select       = select
+local setmetatable = setmetatable
+local create       = coroutine.create
+local isyieldable  = coroutine.isyieldable -- luacheck: ignore
+local resume       = coroutine.resume
+local running      = coroutine.running
+local status       = coroutine.status
+local wrap         = coroutine.wrap
+local yield        = coroutine.yield
+
+local _tagged = setmetatable({}, {__mode = 'kv'})
+
+local _str_tags = setmetatable({}, {__mode = 'v'})
+
+return function(tag)
+  if type(tag) == 'string' then
+     local _tag = _str_tags[tag] or {}
+     _str_tags[tag] = _tag
+     tag = _tag
+  end
+
+  tag = tag or {}
+
+  if _tagged[tag] then
+     return _tagged[tag]
+  end
+
   local coroutine = {
     isyieldable = isyieldable,
     running     = running,
     status      = status,
   }
-  tag = tag or {}
 
+  _tagged[tag] = coroutine
   local function for_wrap (co, ...)
     if tag == ... then
       return select (2, ...)

From acd5e2fe1f2cbedb347fcc5ae0de8372cb2cdd68 Mon Sep 17 00:00:00 2001
From: Sam Atman <atmanistan@gmail.com>
Date: Sat, 26 Mar 2022 09:33:51 -0400
Subject: [PATCH 2/2] Restore space mark for cleaner diff

---
 src/coroutine/make.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/coroutine/make.lua b/src/coroutine/make.lua
index e94eb68..f176ecc 100644
--- a/src/coroutine/make.lua
+++ b/src/coroutine/make.lua
@@ -12,7 +12,7 @@ local _tagged = setmetatable({}, {__mode = 'kv'})
 
 local _str_tags = setmetatable({}, {__mode = 'v'})
 
-return function(tag)
+return function (tag)
   if type(tag) == 'string' then
      local _tag = _str_tags[tag] or {}
      _str_tags[tag] = _tag