Fix override behavior (#538)

AppInspector.RulesEngine/RuleProcessor.cs

@@ -424,21 +424,29 @@ public class RuleProcessor
 
         List<MatchRecord> removes = new();
 
-        foreach (var m in resultsList.Where(x => x.Rule?.Overrides?.Count > 0))
+        foreach (var matchRecord in resultsList.Where(x => x.Rule?.Overrides?.Count > 0))
         {
             if (cancellationToken?.IsCancellationRequested is true)
             {
                 return resultsList;
             }
 
-            foreach (var ovrd in (IList<string>?)m.Rule?.Overrides ?? Array.Empty<string>())
+            foreach (var idToOverride in matchRecord.Rule?.Overrides ?? Array.Empty<string>())
+            {
                 // Find all overriden rules and mark them for removal from issues list
-            foreach (var om in resultsList.FindAll(x => x.Rule?.Id == ovrd))
-                if (om.Boundary.Index >= m.Boundary.Index &&
-                    om.Boundary.Index <= m.Boundary.Index + m.Boundary.Length)
+                foreach (var potentialOverriddenMatch in resultsList.FindAll(x => x.Rule?.Id == idToOverride))
                 {
-                    removes.Add(om);
+                    // Start after or matching start
+                    if (potentialOverriddenMatch.Boundary.Index >= matchRecord.Boundary.Index &&
+                        // End before or matching end
+                        (potentialOverriddenMatch.Boundary.Index + potentialOverriddenMatch.Boundary.Length)
+                            <= (matchRecord.Boundary.Index + matchRecord.Boundary.Length))
+                    {
+                        removes.Add(potentialOverriddenMatch);
+                    }
                 }
+            }
+           
         }
 
         // Remove overriden rules

AppInspector.Tests/RuleProcessor/RuleTests.cs

@@ -1,6 +1,10 @@
+using System.IO;
 using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
 using Microsoft.ApplicationInspector.RulesEngine;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using static Microsoft.CST.RecursiveExtractor.FileEntry;
 
 namespace AppInspector.Tests.RuleProcessor;
 
@@ -65,4 +69,87 @@ public class RuleTests
         rule.Disabled = true;
         Assert.AreEqual(true, rule.Disabled);
     }
+
+    private const string overrideRules = @"[
+    {
+        ""id"": ""SA000005"",
+        ""name"": ""Testing.Rules.Overridee"",
+        ""tags"": [
+            ""Testing.Rules.Overridee""
+        ],
+        ""severity"": ""Critical"",
+        ""description"": ""This rule finds car"",
+        ""patterns"": [
+            {
+                ""pattern"": ""car"",
+                ""type"": ""regex"",
+                ""confidence"": ""High"",
+                ""scopes"": [
+                    ""code""
+                ]
+            }
+        ],
+        ""_comment"": """"
+    },
+    {
+        ""id"": ""SA000006"",
+        ""name"": ""Testing.Rules.Overridee"",
+        ""tags"": [
+            ""Testing.Rules.Overridee""
+        ],
+        ""overrides"": [""SA000005""],
+        ""severity"": ""Critical"",
+        ""description"": ""This rule finds racecar"",
+        ""patterns"": [
+            {
+                ""pattern"": ""racecar"",
+                ""type"": ""regex"",
+                ""confidence"": ""High"",
+                ""scopes"": [
+                    ""code""
+                ]
+            }
+        ],
+        ""_comment"": """"
+    },
+    {
+        ""id"": ""SA000007"",
+        ""name"": ""Testing.Rules.Overridee"",
+        ""tags"": [
+            ""Testing.Rules.Overridee""
+        ],
+        ""overrides"": [""SA000005""],
+        ""severity"": ""Critical"",
+        ""description"": ""This rule finds ar"",
+        ""patterns"": [
+            {
+                ""pattern"": ""ar"",
+                ""type"": ""regex"",
+                ""confidence"": ""High"",
+                ""scopes"": [
+                    ""code""
+                ]
+            }
+        ],
+        ""_comment"": """"
+    }
+]
+";
+    
+    [TestMethod]
+    public async Task Overrides()
+    {
+        RuleSet rules = new();
+        var originalSource = "TestRules";
+        rules.AddString(overrideRules, originalSource);
+        Microsoft.ApplicationInspector.RulesEngine.RuleProcessor processor = new(rules, new RuleProcessorOptions());
+        var entry = await FromStreamAsync("dummy", new MemoryStream(Encoding.UTF8.GetBytes("racecar car")));
+        var langs = new Microsoft.ApplicationInspector.RulesEngine.Languages();
+        langs.FromFileNameOut("dummy.cs", out LanguageInfo info);
+        var results = processor.AnalyzeFile(entry, info);
+        Assert.AreEqual(4, results.Count);
+        Assert.AreEqual(1, results.Count(x=> x.Rule.Id == "SA000006"));
+        Assert.AreEqual(1, results.Count(x=> x.Rule.Id == "SA000005"));
+        Assert.AreEqual(2, results.Count(x=> x.Rule.Id == "SA000007"));
+    }
 }