From dcea5b4f45b2ee0cf33fe300d241e31fadbf8248 Mon Sep 17 00:00:00 2001
From: George Seeger <georgeseeger@hotmail.com>
Date: Wed, 3 Jan 2018 09:07:19 +0000
Subject: [PATCH] Fix for null reference exception on datetime.utcnow.date in
 where clauses

---
 .../Engine/DML/WhereClauseWriterTests.cs      | 21 ++++++++++++++
 Dashing/Engine/DML/WhereClauseWriter.cs       | 28 +++++++++++--------
 2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/Dashing.Tests/Engine/DML/WhereClauseWriterTests.cs b/Dashing.Tests/Engine/DML/WhereClauseWriterTests.cs
index ad7f921d..80d5e616 100644
--- a/Dashing.Tests/Engine/DML/WhereClauseWriterTests.cs
+++ b/Dashing.Tests/Engine/DML/WhereClauseWriterTests.cs
@@ -768,6 +768,27 @@ public void WhereContainsNullableCheck() {
             Assert.Equal(" where ((t_100.[Nullable] is not null) and t_100.[Name] like @l_1)", actual.Sql);
         }
 
+        [Fact]
+        public void DateTimedotNowAsItStands() {
+            var target = MakeTarget();
+            Expression<Func<Comment, bool>> pred = c => c.CommentDate <= DateTime.UtcNow;
+            var now = DateTime.UtcNow;
+            var actual = target.GenerateSql(new[] { pred }, null);
+            var param = (DateTime)actual.Parameters.GetValue("l_1");
+            Assert.Equal(" where ([CommentDate] <= @l_1)", actual.Sql);
+            Assert.True(Math.Abs((param - now).TotalSeconds) < 60); //if it's within a minute, it's just the execution times
+        }
+
+        [Fact]
+        public void DateTimedotDateFix() {
+            var target = MakeTarget();
+            Expression<Func<Comment, bool>> pred = c => c.CommentDate <= DateTime.UtcNow.Date;
+            var actual = target.GenerateSql(new[] { pred }, null);
+            var param = (DateTime)actual.Parameters.GetValue("l_1");
+            Assert.Equal(" where ([CommentDate] <= @l_1)", actual.Sql);
+            Assert.True(DateTime.UtcNow.Date <= param && param <= DateTime.UtcNow.Date);
+        }
+
         private static WhereClauseWriter MakeTarget() {
             return new WhereClauseWriter(new SqlServerDialect(), MakeConfig());
         }
diff --git a/Dashing/Engine/DML/WhereClauseWriter.cs b/Dashing/Engine/DML/WhereClauseWriter.cs
index c7e653b6..5e777759 100644
--- a/Dashing/Engine/DML/WhereClauseWriter.cs
+++ b/Dashing/Engine/DML/WhereClauseWriter.cs
@@ -351,23 +351,27 @@ private ISqlElement VisitMethodCall(MethodCallExpression exp) {
         }
 
         private ISqlElement VisitMemberAccess(MemberExpression exp) {
-            if (exp.Expression == null) {
-                // static property
-                if (this.isTopOfBinaryOrMethod) {
-                    // quicker path
-                    var propInfo = exp.Member as PropertyInfo;
-                    if (propInfo != null) {
-                        return this.AddParameter(propInfo.GetValue(null));
-                    }
-                    var fieldInfo = exp.Member as FieldInfo;
+            if (exp.Expression == null) { // static property
+                
+                //quick path
+                var propInfo = exp.Member as PropertyInfo;
+                if (propInfo != null) {
+                    this.value = propInfo.GetValue(null);
+                } else {
+                     var fieldInfo = exp.Member as FieldInfo;
                     if (fieldInfo != null) {
-                        return this.AddParameter(fieldInfo.GetValue(null));
+                        this.value = fieldInfo.GetValue(null);
+                    } else {
+                            // slow path
+                        this.value = this.GetDynamicValue(exp);
                     }
+                }
 
-                    // slow path
-                    return this.AddParameter(this.GetDynamicValue(exp));
+                if (this.isTopOfBinaryOrMethod) {
+                    return this.AddParameter(this.value);
                 }
 
+                this.isConstantExpression = true;
                 return null;
             }