fix(unittests): do not consider process crash to be a success

unittests relied on the exact setup of coredumps on CI to detect
process crashing, and otherwise completely discarded errors.

Dectect child process failure reliably using process status, so that
unittests actually work locally as well.

1 files changed, 19 insertions, 8 deletions

diff --git a/test/unit/helpers.lua b/test/unit/helpers.lua
index 29ea0235be..4576edf436 100644
--- a/test/unit/helpers.lua
+++ b/test/unit/helpers.lua
@@ -471,8 +471,9 @@ else
     close = ffi.C.close,
     wait = function(pid)
       ffi.errno(0)
+      local stat_loc = ffi.new('int[1]', {0})
       while true do
-        local r = ffi.C.waitpid(pid, nil, ffi.C.kPOSIXWaitWUNTRACED)
+        local r = ffi.C.waitpid(pid, stat_loc, ffi.C.kPOSIXWaitWUNTRACED)
         if r == -1 then
           local err = ffi.errno(0)
           if err == ffi.C.kPOSIXErrnoECHILD then
@@ -485,6 +486,7 @@ else
           assert(r == pid)
         end
       end
+      return stat_loc[0]
     end,
     exit = ffi.C._exit,
   }
@@ -730,18 +732,22 @@ local function check_child_err(rd)
   end
 end
 
-local function itp_parent(rd, pid, allow_failure)
-  local err, emsg = pcall(check_child_err, rd)
-  sc.wait(pid)
+local function itp_parent(rd, pid, allow_failure, location)
+  local ok, emsg = pcall(check_child_err, rd)
+  local status = sc.wait(pid)
   sc.close(rd)
-  if not err then
+  if not ok then
     if allow_failure then
-      io.stderr:write('Errorred out:\n' .. tostring(emsg) .. '\n')
+      io.stderr:write('Errorred out ('..status..'):\n' .. tostring(emsg) .. '\n')
       os.execute([[
         sh -c "source ci/common/test.sh
         check_core_dumps --delete \"]] .. Paths.test_luajit_prg .. [[\""]])
     else
-      error(emsg)
+      error(tostring(emsg)..'\nexit code: '..status)
+    end
+  elseif status ~= 0 then
+    if not allow_failure then
+      error("child process errored out with status "..status.."!\n\n"..location)
     end
   end
 end
@@ -758,6 +764,11 @@ local function gen_itp(it)
       -- FIXME Fix tests with this true
       return
     end
+
+    -- Pre-emptively calculating error location, wasteful, ugh!
+    -- But the way this code messes around with busted implies the real location is strictly
+    -- not available in the parent when an actual error occurs. so we have to do this here.
+    local location = debug.traceback()
     it(name, function()
       local rd, wr = sc.pipe()
       child_pid = sc.fork()
@@ -768,7 +779,7 @@ local function gen_itp(it)
         sc.close(wr)
         local saved_child_pid = child_pid
         child_pid = nil
-        itp_parent(rd, saved_child_pid, allow_failure)
+        itp_parent(rd, saved_child_pid, allow_failure, location)
       end
     end)
   end