SUPPLE: Better support for error messages, show them in the example

7 files changed, 144 insertions, 69 deletions

diff --git a/example/simple-example.lua b/example/simple-example.lua
index 33f62e8..327167f 100644
--- a/example/simple-example.lua
+++ b/example/simple-example.lua
@@ -44,3 +44,12 @@ setmetatable(tab, mt)
 -- Finally, run the subcode
 print(supple.host.run(subcode, "@test-code", tab))
 assert(tab.tot == 24)
+
+-- Now run a supple command which we expect to error out.
+print(supple.host.run("unknown()", "@test-code"))
+
+-- And now, one where we pass an error from host to sandbox and back
+print(supple.host.run("local f = ... f()", "@test-code", function() unknown() end))
+
+-- And now, one where we pass an error from sandbox to host to sandbox and back
+print(supple.host.run("local f = ... f(function() unknown() end)", "@test-code", function(ff) ff() end))
diff --git a/lib/supple/comms.lua b/lib/supple/comms.lua
index efe737f..25aeb39 100644
--- a/lib/supple/comms.lua
+++ b/lib/supple/comms.lua
@@ -18,6 +18,8 @@ local objects = require "supple.objects"
 local unpack = unpack
 local tonumber = tonumber
 local error = error
+local getinfo = debug.getinfo
+local concat = table.concat
 
 local fd = -1
 
@@ -49,67 +51,94 @@ local function recv_msg()
    return str
 end
 
-local function wait_for_response()
-   local back = request.deserialise(recv_msg())
-   -- back could be three things
-   -- an error (raise it)
-   if back.error then
-      error(back.message .. "\n" .. back.traceback)
-   end
-   -- A result, return it
-   if back.error == false then
-      return unpack(back.results)
+local function captcha(msg)
+   local traceback = {}
+   local level = 2
+   local info = getinfo(level, "Snlf")
+   while info do
+      if info.currentline > 0 and 
+	 not info.short_src:match("/supple/[^%.]+%.lua$") then
+	 local ttype, tag = objects.find_tag(info.func)
+	 if ttype then
+	    info.name = tag
+	 end
+	 local line = 
+	    ("\t%s:%d in function %s"):format(info.short_src,
+					      info.currentline,
+					      info.name or "<anon>")
+	 traceback[#traceback+1] = line
+      end
+      level = level + 1
+      info = getinfo(level, "Snlf")
    end
-   -- A method call, call it
+   return {msg, concat(traceback, "\n") or ""}
+end
 
-   local function safe_method(fn)
-      local ok, res = pcall(fn)
-      local resp
-      if not ok then
-	 resp = request.error(res, "")
+local function wait_for_response()
+   repeat
+      local back = request.deserialise(recv_msg())
+      -- back could be three things
+      -- an error (raise it)
+      if back.error then
+	 local msg = back.message
+	 if back.traceback and back.traceback ~= "" then
+	    msg = msg .. "\n" .. back.traceback
+	 end
+	 error(msg, 2)
+      end
+      -- A result, return it
+      if back.error == false then
+	 return unpack(back.results)
+      end
+      -- A method call, call it
+      
+      local function safe_method(fn)
+	 local ok, res = xpcall(fn, captcha)
+	 local resp
+	 if not ok then
+	    resp = request.error(unpack(res))
+	 else
+	    resp = request.response(unpack(res))
+	 end
+	 send_msg(resp)
+      end
+      if back.method == "__gc" then
+	 -- __gc is the garbage collect mechanism
+	 objects.forget_mine(back.object)
+	 send_msg(request.response())
+      elseif back.method == "__call" then
+	 -- __call is the function call mechanism
+	 safe_method(function()
+			local obj = objects.receive { tag = back.object }
+			return {obj(unpack(back.args))}
+		     end)
+      elseif back.method == "__len" then
+	 safe_method(function()
+			local obj = objects.receive { tag = back.object }
+			return {#obj}
+		     end)
+      elseif back.method == "__index" then
+	 safe_method(function()
+			local obj = objects.receive { tag = back.object }
+			return {obj[back.args[1]]}
+		     end)
+      elseif back.method == "__newindex" then
+	 safe_method(function()
+			local obj = objects.receive { tag = back.object }
+			obj[back.args[1]] = back.args[2]
+			return {}
+		     end)
       else
-	 resp = request.response(unpack(res))
+	 safe_method(function()
+			local obj = objects.receive { tag = back.object }
+			local meth = capi.raw_getmm(obj, back.method)
+			if not meth then
+			   error("Unknown or disallowed method: " .. back.method, "")
+			end
+			return {meth(obj, unpack(back.args))}
+		     end)
       end
-      send_msg(resp)
-   end
-   if back.method == "__gc" then
-      -- __gc is the garbage collect mechanism
-      objects.forget_mine(back.object)
-      send_msg(request.response())
-   elseif back.method == "__call" then
-      -- __call is the function call mechanism
-      safe_method(function()
-		     local obj = objects.receive { tag = back.object }
-		     return {obj(unpack(back.args))}
-		  end)
-   elseif back.method == "__len" then
-      safe_method(function()
-		     local obj = objects.receive { tag = back.object }
-		     return {#obj}
-		  end)
-   elseif back.method == "__index" then
-      safe_method(function()
-		     local obj = objects.receive { tag = back.object }
-		     return {obj[back.args[1]]}
-		  end)
-   elseif back.method == "__newindex" then
-      safe_method(function()
-		     local obj = objects.receive { tag = back.object }
-		     obj[back.args[1]] = back.args[2]
-		     return {}
-		  end)
-   else
-      safe_method(function()
-		     local obj = objects.receive { tag = back.object }
-		     local meth = capi.raw_getmm(obj, back.method)
-		     if not meth then
-			error("Unknown or disallowed method: " .. back.method, "")
-		     end
-		     return {meth(obj, unpack(back.args))}
-		  end)
-   end
-   -- And try again
-   return wait_for_response()
+   until false
 end
 
 local function make_call(object, method, ...)
diff --git a/lib/supple/host.lua b/lib/supple/host.lua
index a828046..f0181fa 100644
--- a/lib/supple/host.lua
+++ b/lib/supple/host.lua
@@ -15,6 +15,7 @@ local subprocess = require 'luxio.subprocess'
 local comms = require 'supple.comms'
 local objects = require 'supple.objects'
 
+local hostname = "host"
 local counter = 0
 
 local function run_wrapper()
@@ -50,7 +51,7 @@ local function run_sandbox(codestr, codename, ...)
    local child, commsfd = run_wrapper()
 
    counter = counter + 1
-   objects.set_name(("host-%d"):format(counter))
+   objects.set_name(("host[%d,%%d]"):format(counter))
    comms._set_fd(commsfd)
    objects.set_proc_call(comms.call)
    
@@ -58,21 +59,37 @@ local function run_sandbox(codestr, codename, ...)
    if not func then
       error(err)
    end
+   -- Clear 'err' because it'll be the environment table for the function
+   -- which we do not need to fill out.
+   err = nil
 
-   local ret = {func(...)}
-   
+   -- In a protected manner, capture the output of the call
+   local args, ret = {...}
+   local function capture()
+      ret = {func(unpack(args))}
+   end
+   local ok, err = pcall(capture)
    -- We need to clean up, so dump all the objects
    func = nil
-   err = nil
    -- And ask the supple API to clear down too
    objects.clean_down(true)
 
    comms._set_fd(-1)
    luxio.kill(child.pid, luxio.SIGKILL)
    child:wait()
-   return unpack(ret)
+   if ok then
+      return ok, unpack(ret)
+   else
+      return ok, err
+   end
+end
+
+local function set_hostname(newname)
+   hostname = newname
+   counter = 0
 end
 
 return {
    run = run_sandbox,
+   set_name = set_hostname,
 }
\ No newline at end of file
diff --git a/lib/supple/objects.lua b/lib/supple/objects.lua
index 5aa1ec7..9220502 100644
--- a/lib/supple/objects.lua
+++ b/lib/supple/objects.lua
@@ -56,6 +56,19 @@ local integral = {
    number = true,
 }
 
+local function new_tag(special_tag)
+   local retstr = special_tag
+   if not retstr then
+      if not my_name:match("%%d") then
+	 retstr = ("%s:%d"):format(my_name, my_counter)
+      else
+	 retstr = my_name:format(my_counter)
+      end
+      my_counter = my_counter + 1
+   end
+   return retstr
+end
+
 local function give(obj, special_tag)
    -- If the object is integral, return it directly
    if integral[type(obj)] then
@@ -74,9 +87,7 @@ local function give(obj, special_tag)
       return { tag = tag }
    end
    -- otherwise wrap it freshly for us and return that.
-   local tag = (special_tag and special_tag or 
-		("%s:%d"):format(my_name, my_counter))
-   my_counter = my_counter + 1
+   local tag = new_tag(special_tag)
    local expn = capi.explain(obj, tag)
    my_objects_by_obj[obj] = tag
    my_objects_by_tag[tag] = obj
@@ -135,6 +146,15 @@ local function forget_mine(tag)
    my_objects_by_obj[obj] = nil
 end
 
+local function find_tag(obj)
+   if my_objects_by_obj[obj] then
+      return "my", my_objects_by_obj[obj]
+   end
+   if their_objects_by_obj[obj] then
+      return "their", their_objects_by_obj[obj]
+   end
+end
+
 return {
    set_name = set_name,
    get_name = get_name,
@@ -143,4 +163,5 @@ return {
    receive = receive,
    clean_down = clean_down,
    forget_mine = forget_mine,
+   find_tag = find_tag,
 }
diff --git a/lib/supple/request.lua b/lib/supple/request.lua
index 97f8f4f..ab8388a 100644
--- a/lib/supple/request.lua
+++ b/lib/supple/request.lua
@@ -22,7 +22,7 @@ local setfenv = setfenv
 local function serialise_error(errstr, traceback)
    return tconcat {
       "error=true,",
-      ("message=%q,"):format(("%s: %s"):format(objects.get_name(), errstr)),
+      ("message=%q,"):format(errstr),
       ("traceback=%q"):format(traceback)
    }
 end
diff --git a/lib/supple/sandbox.lua b/lib/supple/sandbox.lua
index 92b3afd..3c807cb 100644
--- a/lib/supple/sandbox.lua
+++ b/lib/supple/sandbox.lua
@@ -118,7 +118,7 @@ local function run()
       return 1
    end
 
-   objects.set_name(("supple-sandbox[%d]"):format(luxio.getpid()))
+   objects.set_name(("supple-sandbox[%d,%%d]"):format(luxio.getpid()))
    objects.set_proc_call(comms.call)
 
    local function wrappered_load(str, name)
diff --git a/test/test-supple.request.lua b/test/test-supple.request.lua
index 2ea7e66..6ed5f5b 100644
--- a/test/test-supple.request.lua
+++ b/test/test-supple.request.lua
@@ -32,9 +32,8 @@ end
 local suite = setmetatable({}, {__newindex = add_test})
 
 function suite.serialise_error()
-   objects.set_name("n")
    local err = request.error("m","tb")
-   assert(err == [[error=true,message="n: m",traceback="tb"]],
+   assert(err == [[error=true,message="m",traceback="tb"]],
 	  "Error did not serialise properly")
 end