Errno::ECHILD thrown from Process.waitpid, some Process methods

lib-topaz/bootstrap.rb

@@ -11,6 +11,7 @@
 load_bootstrap.call("comparable.rb")
 load_bootstrap.call("enumerable.rb")
 load_bootstrap.call("enumerator.rb")
+load_bootstrap.call("errno.rb")
 load_bootstrap.call("file.rb")
 load_bootstrap.call("fixnum.rb")
 load_bootstrap.call("hash.rb")

lib-topaz/errno.rb

@@ -0,0 +1,4 @@
+module Errno
+  class ECHILD < Exception
+  end
+end

spec/tags/core/process/wait_tags.txt

@@ -1,4 +1,3 @@
-fails:Process.wait raises a Errno::ECHILD if there are no child processes
 fails:Process.wait waits for any child process if no pid is given
 fails:Process.wait waits for a specific child if a pid is given
 fails:Process.wait coerces the pid to an Integer

topaz/modules/process.py

@@ -4,6 +4,8 @@
 
 from topaz.module import ModuleDef
 from topaz.system import IS_WINDOWS
+from topaz.objects.classobject import W_ClassObject
+from topaz.objects.moduleobject import W_ModuleObject
 
 
 if IS_WINDOWS:
@@ -35,15 +37,21 @@ def method_pid(self, space):
 
     @moduledef.function("waitpid", pid="int")
     def method_waitpid(self, space, pid=-1):
-        pid, status = os.waitpid(pid, 0)
-        status = WEXITSTATUS(status)
-        w_status = space.send(
-            space.find_const(self, "Status"),
-            "new",
-            [space.newint(pid), space.newint(status)]
-        )
-        space.globals.set(space, "$?", w_status)
-        return space.newint(pid)
+        try:
+            pid, status = os.waitpid(pid, 0)
+            status = WEXITSTATUS(status)
+            w_status = space.send(
+                space.find_const(self, "Status"),
+                "new",
+                [space.newint(pid), space.newint(status)]
+            )
+            space.globals.set(space, "$?", w_status)
+            return space.newint(pid)
+        except OSError as ex:
+            errno = space.find_const(self, "Errno")
+            echild = space.find_const(errno, "ECHILD")
+            assert isinstance(echild, W_ClassObject)
+            raise space.error(echild, str(ex))
 
     @moduledef.function("exit", status="int")
     def method_exit(self, space, status=0):