Merge pull request #2023 from tyrielv/tyrielv/fix-prefetch-merge

Fix build break: bad merge in prefetch cache parameters

Author: tyrielv

GVFS/GVFS.Common/Prefetch/BlobPrefetcher.cs

@@ -688,6 +688,42 @@ private void SavePrefetchArgs(string targetCommit, bool hydrate)
             }
         }
 
+        /// <summary>
+        /// Updates the noop prefetch cache after a successful prefetch that was
+        /// handled externally (e.g. offloaded to the mount process). This mirrors
+        /// the logic in <see cref="SavePrefetchArgs"/> but is callable without a
+        /// BlobPrefetcher instance.
+        /// </summary>
+        public static void UpdateNoopCache(
+            FileBasedDictionary<string, string> prefetchCache,
+            int maxCacheSize,
+            string commitId,
+            List<string> files,
+            List<string> folders,
+            bool hydrate)
+        {
+            if (prefetchCache == null || maxCacheSize <= 0)
+            {
+                return;
+            }
+
+            string cacheKey = ComputeCacheKey(files, folders, hydrate);
+
+            Dictionary<string, string> allEntries = prefetchCache.GetAllKeysAndValues();
+            if (allEntries.Count >= maxCacheSize && !allEntries.ContainsKey(cacheKey))
+            {
+                using (Dictionary<string, string>.Enumerator enumerator = allEntries.GetEnumerator())
+                {
+                    if (enumerator.MoveNext())
+                    {
+                        prefetchCache.RemoveAndFlush(enumerator.Current.Key);
+                    }
+                }
+            }
+
+            prefetchCache.SetValueAndFlush(cacheKey, commitId);
+        }
+
         internal static string ComputeCacheKey(List<string> files, List<string> folders, bool hydrate)
         {
             List<string> sortedFiles = new List<string>(files);

GVFS/GVFS.FunctionalTests/Tests/EnlistmentPerFixture/PrefetchBlobsOffloadTests.cs

@@ -42,12 +42,13 @@ public void PrefetchBlobsMountedReportsStats()
         public void PrefetchBlobsUnmountedFallsBackToDirectAuth()
         {
             // Unmount, then blob prefetch should fall back to direct auth
-            // and still succeed.
+            // and still succeed. Use a file not prefetched by earlier tests
+            // so the noop cache doesn't short-circuit.
             this.Enlistment.UnmountGVFS();
 
             try
             {
-                string output = this.Enlistment.Prefetch($"--files {Path.Combine("GVFS", "GVFS", "Program.cs")}");
+                string output = this.Enlistment.Prefetch($"--files {Path.Combine("GVFS", "GVFS.Common", "GVFSEnlistment.cs")}");
                 output.ShouldContain("Matched blobs:");
                 output.ShouldContain("Downloaded:");
             }
@@ -69,12 +70,14 @@ public void PrefetchBlobsMountedWithFolders()
         public void PrefetchBlobsMountedAfterRemount()
         {
             // After unmount + remount, blob prefetch should work via
-            // the mount process again.
+            // the mount process again. Since this file was already
+            // prefetched in Order(1), the noop cache correctly detects
+            // there's nothing new to download.
             this.Enlistment.UnmountGVFS();
             this.Enlistment.MountGVFS();
 
             string output = this.Enlistment.Prefetch($"--files {Path.Combine("GVFS", "GVFS", "Program.cs")}");
-            output.ShouldContain("Matched blobs:");
+            output.ShouldContain("Nothing new to prefetch.");
         }
     }
 }

GVFS/GVFS.Mount/InProcessMount.cs

@@ -1123,7 +1123,8 @@ private void HandlePrefetchBlobsRequest(NamedPipeMessages.Message message, Named
                         objectRequestor,
                         request.Files,
                         request.Folders,
-                        lastPrefetchArgs,
+                        prefetchCache: null,
+                        maxCacheSize: 0,
                         chunkSize: 4000,
                         searchThreadCount: maxThreads,
                         downloadThreadCount: downloadThreads,

GVFS/GVFS/CommandLine/PrefetchVerb.cs

@@ -231,12 +231,15 @@ protected override void Execute(GVFSEnlistment enlistment)
                                     cacheServerFromConfig,
                                     out objectRequestor,
                                     out resolvedCacheServer);
-                                this.PrefetchBlobs(tracer, enlistment, headCommitId, filesList, foldersList, lastPrefetchArgs, objectRequestor, resolvedCacheServer);
+                                this.PrefetchBlobs(tracer, enlistment, headCommitId, filesList, foldersList, prefetchCache, prefetchCacheSize, objectRequestor, resolvedCacheServer);
                             }
                             else
                             {
-                                // Mount handled download — now hydrate locally
+                                // Mount handled download — hydrate locally, then update noop
+                                // cache. Cache update is after hydration so a hydration failure
+                                // doesn't suppress the retry on the next run.
                                 this.HydrateMatchingFiles(tracer, enlistment, filesList, foldersList);
+                                BlobPrefetcher.UpdateNoopCache(prefetchCache, prefetchCacheSize, headCommitId, filesList, foldersList, this.HydrateFiles);
                             }
                         }
                         else if (!this.TryPrefetchBlobsViaMountProcess(tracer, enlistment, filesList, foldersList, headCommitId))
@@ -251,6 +254,11 @@ protected override void Execute(GVFSEnlistment enlistment)
                                 out resolvedCacheServer);
                             this.PrefetchBlobs(tracer, enlistment, headCommitId, filesList, foldersList, prefetchCache, prefetchCacheSize, objectRequestor, resolvedCacheServer);
                         }
+                        else
+                        {
+                            // Mount handled download — update noop cache so repeat runs are skipped
+                            BlobPrefetcher.UpdateNoopCache(prefetchCache, prefetchCacheSize, headCommitId, filesList, foldersList, hydrate: false);
+                        }
                     }
                 }
                 catch (VerbAbortedException)