Introduce a resume() wrapper to surface coroutine errors.

1 files changed, 20 insertions, 5 deletions

diff --git a/indra/newview/scripts/lua/qtest.lua b/indra/newview/scripts/lua/qtest.lua
index 12e425b7b2..009446d0c3 100644
--- a/indra/newview/scripts/lua/qtest.lua
+++ b/indra/newview/scripts/lua/qtest.lua
@@ -7,6 +7,19 @@ util = require('util')
 
 inspect = require('inspect')
 
+-- resume() wrapper to propagate errors
+function resume(co, ...)
+    -- if there's an idiom other than table.pack() to assign an arbitrary
+    -- number of return values, I don't yet know it
+    local ok_result = table.pack(coroutine.resume(co, ...))
+    if not ok_result[1] then
+        -- if [1] is false, then [2] is the error message
+        error(ok_result[2])
+    end
+    -- ok is true, whew, just return the rest of the values
+    return table.unpack(ok_result, 2)
+end
+
 -- ------------------ Queue variables are instance-specific ------------------
 q1 = Queue:new()
 q2 = Queue:new()
@@ -51,9 +64,9 @@ coa = coroutine.create(consumer)
 cob = coroutine.create(consumer)
 -- Since consumer() doesn't yield while it can still retrieve values,
 -- consumer(a) will dequeue all values from q1 and return when done.
-coroutine.resume(coa, 'a', q1)
+resume(coa, 'a', q1)
 -- consumer(b) will wake up to find the queue empty and closed.
-coroutine.resume(cob, 'b', q1)
+resume(cob, 'b', q1)
 coroutine.close(coa)
 coroutine.close(cob)
 
@@ -72,7 +85,7 @@ for _, name in {'a', 'b'} do
     local coro = coroutine.create(consumer)
     table.insert(coros, coro)
     -- Resuming both coroutines should leave them both waiting for a queue item.
-    coroutine.resume(coro, name, q3)
+    resume(coro, name, q3)
 end
 
 for _, s in pairs(values) do
@@ -89,6 +102,8 @@ function joinall(coros)
         for i, coro in pairs(coros) do
             if coroutine.status(coro) == 'suspended' then
                 running = true
+                -- directly call coroutine.resume() instead of our resume()
+                -- wrapper because we explicitly check for errors here
                 local ok, message = coroutine.resume(coro)
                 if not ok then
                     print('*** ' .. message)
@@ -105,7 +120,7 @@ end
 
 joinall(coros)
 
-print(string.format('%q', util.join(result, ' ')))
+print(string.format('%q', table.concat(result, ' ')))
 assert(util.equal(values, result))
 
 -- ----------------------------- test ErrorQueue -----------------------------
@@ -118,7 +133,7 @@ for _, name in {'a', 'b'} do
     local coro = coroutine.create(consumer)
     table.insert(coros, coro)
     -- Resuming both coroutines should leave them both waiting for a queue item.
-    coroutine.resume(coro, name, q4)
+    resume(coro, name, q4)
 end
 
 for i = 1, 4 do