From 8bcb8b4ddd09315bcbda2d3f9a274a81c911f2d7 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 1 Nov 2026 21:19:03 +0000
Subject: [PATCH 1/2] Initial plan


From 7a38a16f32dd0a734500da3b2f92c8d51788c8f9 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 1 Nov 2026 21:23:29 +0000
Subject: [PATCH 2/2] Skip Dockerfile-specific dockerignore files without
 warnings

Co-authored-by: grvillic <58237075+grvillic@users.noreply.github.com>
---
 .../dockerfile/DockerfileComponentDetector.cs |  1 +
 .../DockerfileComponentDetectorTests.cs       | 34 +++++++++++++++++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs b/src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs
index 00760e336..a4c2f92b0 100644
--- a/src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs
+++ b/src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs
@@ -51,6 +51,7 @@ protected override Task<IObservable<ProcessRequest>> OnPrepareDetectionAsync(
         IDictionary<string, string> detectorArgs,
         CancellationToken cancellationToken = default) =>
         Task.FromResult(processRequests.Where(processRequest =>
+            !processRequest.ComponentStream.Location.EndsWith(".dockerignore", StringComparison.OrdinalIgnoreCase) &&
             !this.IsInSkippedFolder(processRequest.ComponentStream.Location)));
 
     protected override async Task OnFileFoundAsync(ProcessRequest processRequest, IDictionary<string, string> detectorArgs, CancellationToken cancellationToken = default)
diff --git a/test/Microsoft.ComponentDetection.Detectors.Tests/DockerfileComponentDetectorTests.cs b/test/Microsoft.ComponentDetection.Detectors.Tests/DockerfileComponentDetectorTests.cs
index 90d685172..5bfb14f0e 100644
--- a/test/Microsoft.ComponentDetection.Detectors.Tests/DockerfileComponentDetectorTests.cs
+++ b/test/Microsoft.ComponentDetection.Detectors.Tests/DockerfileComponentDetectorTests.cs
@@ -201,18 +201,48 @@ public async Task TestDockerfile_ExtensionFilenameAsync()
     }
 
     [TestMethod]
-    public async Task TestDockerfile_PrefixedFilenameAsync()
+    [DataRow("Dockerfile.prod")]
+    [DataRow("Dockerfile.runtime")]
+    [DataRow("Dockerfile.dockerignore.runtime")]
+    public async Task TestDockerfile_PrefixedFilenameAsync(string fileName)
     {
         var dockerfile = @"FROM redis:7-alpine";
 
         var (scanResult, componentRecorder) = await this.DetectorTestUtility
-            .WithFile("Dockerfile.prod", dockerfile)
+            .WithFile(fileName, dockerfile)
             .ExecuteDetectorAsync();
 
         scanResult.ResultCode.Should().Be(ProcessingResultCode.Success);
         componentRecorder.GetDetectedComponents().Should().ContainSingle();
     }
 
+    [TestMethod]
+    [DataRow("Dockerfile.dockerignore", "node_modules\n*.log")]
+    [DataRow("Dockerfile.runtime.dockerignore", "node_modules\n*.log")]
+    [DataRow("app.dockerfile.dockerignore", "node_modules\n*.log")]
+    [DataRow("DOCKERFILE.DOCKERIGNORE", "node_modules\n*.log")]
+    [DataRow("Dockerfile.dockerignore", "FROM redis:7-alpine")]
+    public async Task TestDockerfile_DockerignoreIsSilentlyIgnoredAsync(string fileName, string contents)
+    {
+        var loggerMock = new Mock<ILogger<DockerfileComponentDetector>>();
+
+        var (scanResult, componentRecorder) = await this.DetectorTestUtility
+            .WithFile(fileName, contents)
+            .AddServiceMock(loggerMock)
+            .ExecuteDetectorAsync();
+
+        scanResult.ResultCode.Should().Be(ProcessingResultCode.Success);
+        componentRecorder.GetDetectedComponents().Should().BeEmpty();
+        loggerMock.Verify(
+            logger => logger.Log(
+                It.Is<LogLevel>(level => level == LogLevel.Warning || level == LogLevel.Error),
+                It.IsAny<EventId>(),
+                It.IsAny<It.IsAnyType>(),
+                It.IsAny<Exception>(),
+                It.IsAny<Func<It.IsAnyType, Exception?, string>>()),
+            Times.Never);
+    }
+
     [TestMethod]
     [DataRow("dockerfile.mjs")]
     [DataRow("dockerfile.d.mts")]