[Fixes #7658] FileStreamResultExecutor fails to Dispose FileStream

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/FileStreamResultExecutor.cs

@@ -17,7 +17,7 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
         }
 
         /// <inheritdoc />
-        public virtual Task ExecuteAsync(ActionContext context, FileStreamResult result)
+        public virtual async Task ExecuteAsync(ActionContext context, FileStreamResult result)
         {
             if (context == null)
             {
@@ -29,31 +29,38 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
                 throw new ArgumentNullException(nameof(result));
             }
 
-            Logger.ExecutingFileResult(result);
+            using (result.FileStream)
-
-            long? fileLength = null;
-            if (result.FileStream.CanSeek)
             {
-                fileLength = result.FileStream.Length;
+                Logger.ExecutingFileResult(result);
+
+                long? fileLength = null;
+                if (result.FileStream.CanSeek)
+                {
+                    fileLength = result.FileStream.Length;
+                }
+
+                var (range, rangeLength, serveBody) = SetHeadersAndLog(
+                    context,
+                    result,
+                    fileLength,
+                    result.EnableRangeProcessing,
+                    result.LastModified,
+                    result.EntityTag);
+
+                if (!serveBody)
+                {
+                    return;
+                }
+
+                await WriteFileAsync(context, result, range, rangeLength);
             }
-
-            var (range, rangeLength, serveBody) = SetHeadersAndLog(
-                context,
-                result,
-                fileLength,
-                result.EnableRangeProcessing,
-                result.LastModified,
-                result.EntityTag);
-
-            if (!serveBody)
-            {
-                return Task.CompletedTask;
-            }
-
-            return WriteFileAsync(context, result, range, rangeLength);
         }
 
-        protected virtual Task WriteFileAsync(ActionContext context, FileStreamResult result, RangeItemHeaderValue range, long rangeLength)
+        protected virtual Task WriteFileAsync(
+            ActionContext context,
+            FileStreamResult result,
+            RangeItemHeaderValue range,
+            long rangeLength)
         {
             if (context == null)
             {

test/Microsoft.AspNetCore.Mvc.Core.Test/FileStreamResultTest.cs

@@ -126,6 +126,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(contentRange.ToString(), httpResponse.Headers[HeaderNames.ContentRange]);
             Assert.Equal(contentLength, httpResponse.ContentLength);
             Assert.Equal(expectedString, body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Fact]
@@ -174,6 +175,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(contentRange.ToString(), httpResponse.Headers[HeaderNames.ContentRange]);
             Assert.Equal(5, httpResponse.ContentLength);
             Assert.Equal("Hello", body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Fact]
@@ -217,6 +219,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(lastModified.ToString("R"), httpResponse.Headers[HeaderNames.LastModified]);
             Assert.Equal(entityTag.ToString(), httpResponse.Headers[HeaderNames.ETag]);
             Assert.Equal("Hello World", body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Fact]
@@ -261,6 +264,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(lastModified.ToString("R"), httpResponse.Headers[HeaderNames.LastModified]);
             Assert.Equal(entityTag.ToString(), httpResponse.Headers[HeaderNames.ETag]);
             Assert.Equal("Hello World", body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Theory]
@@ -303,6 +307,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(lastModified.ToString("R"), httpResponse.Headers[HeaderNames.LastModified]);
             Assert.Equal(entityTag.ToString(), httpResponse.Headers[HeaderNames.ETag]);
             Assert.Equal("Hello World", body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Theory]
@@ -346,6 +351,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(contentRange.ToString(), httpResponse.Headers[HeaderNames.ContentRange]);
             Assert.Equal(11, httpResponse.ContentLength);
             Assert.Empty(body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Fact]
@@ -389,6 +395,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Empty(httpResponse.Headers[HeaderNames.ContentRange]);
             Assert.NotEmpty(httpResponse.Headers[HeaderNames.LastModified]);
             Assert.Empty(body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Fact]
@@ -432,6 +439,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Empty(httpResponse.Headers[HeaderNames.ContentRange]);
             Assert.NotEmpty(httpResponse.Headers[HeaderNames.LastModified]);
             Assert.Empty(body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Theory]
@@ -480,6 +488,7 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal("bytes", httpResponse.Headers[HeaderNames.AcceptRanges]);
             Assert.Equal(contentRange.ToString(), httpResponse.Headers[HeaderNames.ContentRange]);
             Assert.Empty(body);
+            Assert.False(readStream.CanSeek);
         }
 
         [Fact]
@@ -541,6 +550,7 @@ namespace Microsoft.AspNetCore.Mvc
             // Assert
             var outBytes = outStream.ToArray();
             Assert.True(originalBytes.SequenceEqual(outBytes));
+            Assert.False(originalStream.CanSeek);
         }
 
         [Fact]
@@ -570,6 +580,31 @@ namespace Microsoft.AspNetCore.Mvc
             var outBytes = outStream.ToArray();
             Assert.True(originalBytes.SequenceEqual(outBytes));
             Assert.Equal(expectedContentType, httpContext.Response.ContentType);
+            Assert.False(originalStream.CanSeek);
+        }
+
+        [Fact]
+        public async Task HeadRequest_DoesNotWriteToBody_AndClosesReadStream()
+        {
+            // Arrange
+            var readStream = new MemoryStream(Encoding.UTF8.GetBytes("Hello, World!"));
+
+            var httpContext = GetHttpContext();
+            httpContext.Request.Method = "HEAD";
+            var outStream = new MemoryStream();
+            httpContext.Response.Body = outStream;
+
+            var actionContext = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
+
+            var result = new FileStreamResult(readStream, "text/plain");
+
+            // Act
+            await result.ExecuteResultAsync(actionContext);
+
+            // Assert
+            Assert.False(readStream.CanSeek);
+            Assert.Equal(200, httpContext.Response.StatusCode);
+            Assert.Equal(0, httpContext.Response.Body.Length);
         }
 
         private static IServiceCollection CreateServices()