Issue #547 : debug.getinfo reports source and short_src as Lua 5.1

_glua-tests/db.lua

@@ -19,9 +19,9 @@ local function f2()
   assert(info.nups == 1)
   assert(info.name == "f2")
   assert(info.what == "Lua")
-  if string.find(_VERSION, "GopherLua") then
-    assert(info.source == "db.lua")
-  end
+  assert(info.source == "@db.lua")
+  assert(info.short_src == "db.lua")
+  assert(debug.getinfo(2, "S").short_src == "db.lua")
 end
 f2()
 
@@ -35,9 +35,18 @@ assert(info.lastlinedefined == 29)
 assert(info.nups == 0)
 assert(info.name == nil)
 assert(info.what == "Lua")
-if string.find(_VERSION, "GopherLua") then
-  assert(info.source == "db.lua")
-end
+assert(info.source == "@db.lua")
+assert(info.short_src == "db.lua")
+
+-- source and short_src as in Lua 5.1 (#547)
+local s = debug.getinfo(print, "S")
+assert(s.source == "=[C]" and s.short_src == "[C]")
+s = loadstring("return debug.getinfo(1, 'S')", "=custom")()
+assert(s.source == "=custom" and s.short_src == "custom")
+s = loadstring("return debug.getinfo(1, 'S')", "@virtual.lua")()
+assert(s.source == "@virtual.lua" and s.short_src == "virtual.lua")
+s = loadstring("return debug.getinfo(1, 'S')", "chunk\nsecond line")()
+assert(s.short_src == '[string "chunk..."]')
 
 local function f4()
   local a,b,c = 1,2,3

_state.go

@@ -1556,8 +1556,13 @@ func (ls *LState) GetInfo(what string, dbg *Debug, fn LValue) (LValue, error) {
 			} else {
 				dbg.What = "Lua"
 			}
-			if !f.IsG {
+			if f.IsG {
+				dbg.Source = "=[C]" // as Lua 5.1 reports a function that is not Lua code
+			} else {
 				dbg.Source = f.Proto.SourceName
+				if f.Proto.fromFile {
+					dbg.Source = "@" + f.Proto.SourceName
+				}
 				dbg.LineDefined = f.Proto.LineDefined
 				dbg.LastLineDefined = f.Proto.LastLineDefined
 			}

auxlib.go

@@ -386,7 +386,18 @@ func (ls *LState) LoadFile(path string) (*LFunction, error) {
 		}
 	}
 
-	return ls.Load(reader, path)
+	fn, err := ls.Load(reader, path)
+	if err == nil && len(path) > 0 {
+		markLoadedFromFile(fn.Proto)
+	}
+	return fn, err
+}
+
+func markLoadedFromFile(proto *FunctionProto) {
+	proto.fromFile = true
+	for _, p := range proto.FunctionPrototypes {
+		markLoadedFromFile(p)
+	}
 }
 
 func (ls *LState) LoadString(source string) (*LFunction, error) {

debuglib.go

@@ -62,6 +62,7 @@ func debugGetInfo(L *LState) int {
 	}
 	tbl.RawSetString("what", LString(dbg.What))
 	tbl.RawSetString("source", LString(dbg.Source))
+	tbl.RawSetString("short_src", LString(chunkID(dbg.Source)))
 	tbl.RawSetString("currentline", LNumber(dbg.CurrentLine))
 	tbl.RawSetString("nups", LNumber(dbg.NUpvalues))
 	tbl.RawSetString("linedefined", LNumber(dbg.LineDefined))
@@ -171,3 +172,36 @@ func debugTraceback(L *LState) int {
 	L.Push(LString(traceback))
 	return 1
 }
+
+// chunkID is the short_src of a source, as luaO_chunkid in Lua 5.1:
+// "=name" -> name, "@file" -> file, a string chunk -> [string "first line..."].
+func chunkID(source string) string {
+	const idSize = 60
+	switch {
+	case strings.HasPrefix(source, "="):
+		s := source[1:]
+		if len(s) > idSize-1 {
+			s = s[:idSize-1]
+		}
+		return s
+	case strings.HasPrefix(source, "@"):
+		s := source[1:]
+		if len(s) > idSize-1 {
+			s = "..." + s[len(s)-(idSize-1-3):]
+		}
+		return s
+	default:
+		s := source
+		cut := false
+		if i := strings.IndexAny(s, "\r\n"); i >= 0 {
+			s, cut = s[:i], true
+		}
+		if max := idSize - len(`[string "..."]`) - 1; len(s) > max {
+			s, cut = s[:max], true
+		}
+		if cut {
+			s += "..."
+		}
+		return `[string "` + s + `"]`
+	}
+}

function.go

@@ -39,6 +39,8 @@ type FunctionProto struct {
 	DbgCalls           []DbgCall
 	DbgUpvalues        []string
 
+	fromFile bool // loaded by LoadFile: debug info reports the source as "@" + SourceName
+
 	stringConstants []string
 }
 

state.go

@@ -1769,8 +1769,13 @@ func (ls *LState) GetInfo(what string, dbg *Debug, fn LValue) (LValue, error) {
 			} else {
 				dbg.What = "Lua"
 			}
-			if !f.IsG {
+			if f.IsG {
+				dbg.Source = "=[C]" // as Lua 5.1 reports a function that is not Lua code
+			} else {
 				dbg.Source = f.Proto.SourceName
+				if f.Proto.fromFile {
+					dbg.Source = "@" + f.Proto.SourceName
+				}
 				dbg.LineDefined = f.Proto.LineDefined
 				dbg.LastLineDefined = f.Proto.LastLineDefined
 			}