fix(coroutine): rethrow errors from cb_to_co

lua/coerce/coroutine.lua

@@ -34,6 +34,9 @@ M.cb_to_co = function(f)
 				-- If we are suspended, then we f_co has yielded control after calling f.
 				-- Use the caller of this callback to resume computation until the next yield.
 				local cb_ret = { coroutine.resume(this) }
+				if not cb_ret[1] then
+					error(cb_ret[2])
+				end
 				return unpack(shift(cb_ret))
 			end
 		end, ...)

neovim.yml

@@ -9,6 +9,9 @@ globals:
       - type: bool
       - type: string
         required: false
+  assert.has.errors:
+    args:
+      - type: function
   assert.are.same:
     args:
       - type: any

tests/coerce/coroutine_spec.lua

@@ -61,5 +61,27 @@ describe("coerce.coroutine", function()
 			assert.are.same(3, f_co_ret_sum)
 			assert.are.same(2, f_co_ret_mul)
 		end)
+
+		it("rethrows errors after callback", function()
+			local f_cb = function() end
+
+			-- f is a function that will “execute” the callback asynchronously through f_cb.
+			local f = function(cb)
+				f_cb = function()
+					return cb()
+				end
+			end
+
+			local f_co = coroutine.create(function()
+				cco.cb_to_co(f)()
+				error("Catch me!")
+			end)
+
+			-- Resume the coroutine, which will call f and yield.
+			coroutine.resume(f_co)
+
+			-- Simulate the callback being called asynchronously.
+			assert.has.errors(f_cb)
+		end)
 	end)
 end)