From b2f90f832ad62268e8a0aabd77b7c4cc5dbde9a2 Mon Sep 17 00:00:00 2001
From: Nikolay Turpitko <nikolay@turpitko.com>
Date: Thu, 21 Jan 2016 23:48:19 +0600
Subject: [PATCH] Lua script, HMGET, value for absent key #219

---
 server/script.go      | 19 ++++++++++++++++++-
 server/script_test.go | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/server/script.go b/server/script.go
index d15dfbd..8e6b14f 100644
--- a/server/script.go
+++ b/server/script.go
@@ -84,8 +84,25 @@ func (w *luaWriter) writeSliceArray(lst [][]byte) {
 
 	w.l.CreateTable(len(lst), 0)
 	for i, v := range lst {
-		w.l.PushString(hack.String(v))
+		if v == nil {
+			w.l.PushBoolean(false)
+			//TNL: not sure what is "expected" behaviour here.
+			//Redis returns "false", but may be "nil" is more appropriate?
+			//For me both variants seems better, then empty string.
+			//
+			//w.l.PushNil()
+		} else {
+			w.l.PushString(hack.String(v))
+		}
 		w.l.RawSeti(-2, i+1)
+
+		/*
+			//TNL: and instead of push nil we can just skip it
+			if v != nil {
+				w.l.PushString(hack.String(v))
+				w.l.RawSeti(-2, i+1)
+			}
+		*/
 	}
 }
 
diff --git a/server/script_test.go b/server/script_test.go
index 0446bb7..bae27ff 100644
--- a/server/script_test.go
+++ b/server/script_test.go
@@ -105,6 +105,15 @@ var testScript5 = `
     return ledis.call("PING")
 `
 
+var testScript6 = `
+	ledis.call('hmset', 'zzz', 1, 2, 5, 42)
+	local a = ledis.call('hmget', 'zzz', 1, 2, 5, 42)
+	for i = 1, 5 do
+		a[i] = type(a[i])
+	end
+	return a
+`
+
 func TestLuaCall(t *testing.T) {
 	cfg := config.NewConfigDefault()
 	cfg.Addr = ":11188"
@@ -187,5 +196,29 @@ func TestLuaCall(t *testing.T) {
 		t.Fatal(fmt.Sprintf("%v %T", v, v))
 	}
 
+	err = app.script.l.DoString(testScript6)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	v = luaReplyToLedisReply(l)
+	vv := v.([]interface{})
+	expected := []string{
+		"string",
+		"boolean",
+		"string",
+		"boolean",
+		"nil",
+	}
+	if len(expected) != len(vv) {
+		t.Fatalf("length different: %d, %d", len(expected), len(vv))
+	}
+	for i, r := range vv {
+		s := string(r.([]byte))
+		if s != expected[i] {
+			t.Errorf("reply[%d] expected: %s, actual: %s", i, expected[i], s)
+		}
+	}
+
 	luaClient.db = nil
 }