From d367726709f1d8698b571f04f1831d680523edf4 Mon Sep 17 00:00:00 2001
From: Tobie Morgan Hitchcock <tobie@abcum.com>
Date: Sun, 3 Dec 2017 00:48:50 +0000
Subject: [PATCH] Ensure NULL/VOID/EMPTY values are compared correctly

---
 db/fetch.go       | 178 ++++++++++++++++++++++++++++++----------------
 db/select_test.go |  90 +++++++++++++++++++++++
 2 files changed, 207 insertions(+), 61 deletions(-)

diff --git a/db/fetch.go b/db/fetch.go
index a2a869ad..e8e0561b 100644
--- a/db/fetch.go
+++ b/db/fetch.go
@@ -409,94 +409,150 @@ func binaryMath(op sql.Token, l, r interface{}) interface{} {
 
 func binaryCheck(op sql.Token, l, r, lo, ro interface{}, d *data.Doc) interface{} {
 
+	switch lo.(type) {
+	case *sql.Void:
+		switch ro.(type) {
+		default:
+			return op == sql.NEQ
+		case nil:
+			return op == sql.NEQ
+		case *sql.Void:
+			return op == sql.EQ
+		case *sql.Empty:
+			return op == sql.EQ
+		case *sql.Ident:
+			break
+		}
+	case *sql.Empty:
+		switch ro.(type) {
+		default:
+			return op == sql.NEQ
+		case nil:
+			return op == sql.EQ
+		case *sql.Void:
+			return op == sql.EQ
+		case *sql.Empty:
+			return op == sql.EQ
+		case *sql.Param:
+			break
+		case *sql.Ident:
+			break
+		}
+	}
+
+	switch ro.(type) {
+	case *sql.Void:
+		switch lo.(type) {
+		default:
+			return op == sql.NEQ
+		case nil:
+			return op == sql.NEQ
+		case *sql.Void:
+			return op == sql.EQ
+		case *sql.Empty:
+			return op == sql.EQ
+		case *sql.Ident:
+			break
+		}
+	case *sql.Empty:
+		switch lo.(type) {
+		default:
+			return op == sql.NEQ
+		case nil:
+			return op == sql.EQ
+		case *sql.Void:
+			return op == sql.EQ
+		case *sql.Empty:
+			return op == sql.EQ
+		case *sql.Param:
+			break
+		case *sql.Ident:
+			break
+		}
+	}
+
 	if d != nil {
 
-		switch l := lo.(type) {
-
+		switch lo.(type) {
 		case *sql.Void:
-
-			switch r.(type) {
-			case nil:
-				return op == sql.NEQ
-			}
-
-		case *sql.Ident:
-
-			switch r.(type) {
-
-			case *sql.Void:
-				if op == sql.EQ {
-					return d.Exists(l.ID) == false
-				} else if op == sql.NEQ {
-					return d.Exists(l.ID) == true
-				}
-
-			case nil:
-				if op == sql.EQ {
-					return d.Exists(l.ID) == true && d.Get(l.ID).Data() == nil
-				} else if op == sql.NEQ {
-					return d.Exists(l.ID) == false || d.Get(l.ID).Data() != nil
-				}
-
-			case *sql.Empty:
-				if op == sql.EQ {
-					return d.Exists(l.ID) == false || d.Get(l.ID).Data() == nil
-				} else if op == sql.NEQ {
-					return d.Exists(l.ID) == true && d.Get(l.ID).Data() != nil
-				}
-
-			}
-
-		}
-
-		switch r := ro.(type) {
-
-		case *sql.Void:
-
-			switch l.(type) {
-			case nil:
-				return op == sql.NEQ
-			}
-
-		case *sql.Ident:
-
-			switch l.(type) {
-
-			case *sql.Void:
+			switch r := ro.(type) {
+			case *sql.Ident:
 				if op == sql.EQ {
 					return d.Exists(r.ID) == false
 				} else if op == sql.NEQ {
 					return d.Exists(r.ID) == true
 				}
-
-			case nil:
-				if op == sql.EQ {
-					return d.Exists(r.ID) == true && d.Get(r.ID).Data() == nil
-				} else if op == sql.NEQ {
-					return d.Exists(r.ID) == false || d.Get(r.ID).Data() != nil
-				}
-
-			case *sql.Empty:
+			}
+		case *sql.Empty:
+			switch r := ro.(type) {
+			case *sql.Ident:
 				if op == sql.EQ {
 					return d.Exists(r.ID) == false || d.Get(r.ID).Data() == nil
 				} else if op == sql.NEQ {
 					return d.Exists(r.ID) == true && d.Get(r.ID).Data() != nil
 				}
-
 			}
+		case nil:
+			switch r := ro.(type) {
+			case *sql.Ident:
+				if op == sql.EQ {
+					return d.Exists(r.ID) == true && d.Get(r.ID).Data() == nil
+				} else if op == sql.NEQ {
+					return d.Exists(r.ID) == false || d.Get(r.ID).Data() != nil
+				}
+			}
+		}
 
+		switch ro.(type) {
+		case *sql.Void:
+			switch l := lo.(type) {
+			case *sql.Ident:
+				if op == sql.EQ {
+					return d.Exists(l.ID) == false
+				} else if op == sql.NEQ {
+					return d.Exists(l.ID) == true
+				}
+			}
+		case *sql.Empty:
+			switch l := lo.(type) {
+			case *sql.Ident:
+				if op == sql.EQ {
+					return d.Exists(l.ID) == false || d.Get(l.ID).Data() == nil
+				} else if op == sql.NEQ {
+					return d.Exists(l.ID) == true && d.Get(l.ID).Data() != nil
+				}
+			}
+		case nil:
+			switch l := lo.(type) {
+			case *sql.Ident:
+				if op == sql.EQ {
+					return d.Exists(l.ID) == true && d.Get(l.ID).Data() == nil
+				} else if op == sql.NEQ {
+					return d.Exists(l.ID) == false || d.Get(l.ID).Data() != nil
+				}
+			}
 		}
 
 	}
 
 	switch l := l.(type) {
 
+	case *sql.Empty:
+		switch r.(type) {
+		default:
+			return op == sql.NEQ || op == sql.SNI || op == sql.NIS || op == sql.CONTAINSNONE
+		case nil:
+			return op == sql.EQ
+		}
+
 	case nil:
 		switch r := r.(type) {
 		default:
 			return op == sql.NEQ || op == sql.SNI || op == sql.NIS || op == sql.CONTAINSNONE
 		case nil:
 			return op == sql.EQ
+		case *sql.Empty:
+			return op == sql.EQ
 		case []interface{}:
 			return chkArrayR(op, l, r)
 		case map[string]interface{}:
diff --git a/db/select_test.go b/db/select_test.go
index 4b42403a..c7b07f76 100644
--- a/db/select_test.go
+++ b/db/select_test.go
@@ -24,6 +24,96 @@ import (
 
 func TestSelect(t *testing.T) {
 
+	Convey("Select temps", t, func() {
+
+		setupDB()
+
+		txt := `
+
+		USE NS test DB test;
+
+		LET var = NULL;
+
+		SELECT * FROM "test" WHERE NULL = "";
+		SELECT * FROM "test" WHERE NULL = $var;
+		SELECT * FROM "test" WHERE NULL = VOID;
+		SELECT * FROM "test" WHERE NULL = NULL;
+		SELECT * FROM "test" WHERE NULL = EMPTY;
+
+		SELECT * FROM "test" WHERE "" = NULL;
+		SELECT * FROM "test" WHERE $var = NULL;
+		SELECT * FROM "test" WHERE VOID = NULL;
+		SELECT * FROM "test" WHERE NULL = NULL;
+		SELECT * FROM "test" WHERE EMPTY = NULL;
+
+		SELECT * FROM "test" WHERE VOID = "";
+		SELECT * FROM "test" WHERE VOID = $var;
+		SELECT * FROM "test" WHERE VOID = NULL;
+		SELECT * FROM "test" WHERE VOID = VOID;
+		SELECT * FROM "test" WHERE VOID = EMPTY;
+
+		SELECT * FROM "test" WHERE "" = VOID;
+		SELECT * FROM "test" WHERE $var = VOID;
+		SELECT * FROM "test" WHERE NULL = VOID;
+		SELECT * FROM "test" WHERE VOID = VOID;
+		SELECT * FROM "test" WHERE EMPTY = VOID;
+
+		SELECT * FROM "test" WHERE EMPTY = "";
+		SELECT * FROM "test" WHERE EMPTY = $var;
+		SELECT * FROM "test" WHERE EMPTY = NULL;
+		SELECT * FROM "test" WHERE EMPTY = VOID;
+		SELECT * FROM "test" WHERE EMPTY = EMPTY;
+
+		SELECT * FROM "test" WHERE "" = EMPTY;
+		SELECT * FROM "test" WHERE $var = EMPTY;
+		SELECT * FROM "test" WHERE NULL = EMPTY;
+		SELECT * FROM "test" WHERE VOID = EMPTY;
+		SELECT * FROM "test" WHERE EMPTY = EMPTY;
+
+		`
+
+		res, err := Execute(setupKV(), txt, nil)
+		So(err, ShouldBeNil)
+		So(res, ShouldHaveLength, 32)
+
+		So(res[2].Result, ShouldHaveLength, 0)
+		So(res[3].Result, ShouldHaveLength, 1)
+		So(res[4].Result, ShouldHaveLength, 0)
+		So(res[5].Result, ShouldHaveLength, 1)
+		So(res[6].Result, ShouldHaveLength, 1)
+
+		So(res[7].Result, ShouldHaveLength, 0)
+		So(res[8].Result, ShouldHaveLength, 1)
+		So(res[9].Result, ShouldHaveLength, 0)
+		So(res[10].Result, ShouldHaveLength, 1)
+		So(res[11].Result, ShouldHaveLength, 1)
+
+		So(res[12].Result, ShouldHaveLength, 0)
+		So(res[13].Result, ShouldHaveLength, 0)
+		So(res[14].Result, ShouldHaveLength, 0)
+		So(res[15].Result, ShouldHaveLength, 1)
+		So(res[16].Result, ShouldHaveLength, 1)
+
+		So(res[17].Result, ShouldHaveLength, 0)
+		So(res[18].Result, ShouldHaveLength, 0)
+		So(res[19].Result, ShouldHaveLength, 0)
+		So(res[20].Result, ShouldHaveLength, 1)
+		So(res[21].Result, ShouldHaveLength, 1)
+
+		So(res[22].Result, ShouldHaveLength, 0)
+		So(res[23].Result, ShouldHaveLength, 1)
+		So(res[24].Result, ShouldHaveLength, 1)
+		So(res[25].Result, ShouldHaveLength, 1)
+		So(res[26].Result, ShouldHaveLength, 1)
+
+		So(res[27].Result, ShouldHaveLength, 0)
+		So(res[28].Result, ShouldHaveLength, 1)
+		So(res[29].Result, ShouldHaveLength, 1)
+		So(res[30].Result, ShouldHaveLength, 1)
+		So(res[31].Result, ShouldHaveLength, 1)
+
+	})
+
 	Convey("Select records from one thing", t, func() {
 
 		setupDB()