Config flag for showing hydration status

Some users are reporting issues (both performance and reliability) with
the new hydration status feature.

* Add a config flag to enable or disable hydration status calculation
and reporting as part of git status. The flag is disabled by default.
* Add "--porcelain" as an arg that disables hydration status reporting
for scripting scenarios.
* Update the "run gvfs health for details" message to clarify that it
should be run at the repo root to correspond to the summary.

Author: tyrielv

GVFS/GVFS.Common/Enlistment.cs

@@ -122,5 +122,18 @@ public bool GetTrustPackIndexesConfig()
 
             return trustPackIndexes;
         }
+
+        public bool GetStatusHydrationConfig()
+        {
+            var gitProcess = this.CreateGitProcess();
+
+            if (gitProcess.TryGetFromConfig(GVFSConstants.GitConfig.ShowHydrationStatus, forceOutsideEnlistment: false, out var valueString)
+                && bool.TryParse(valueString, out var statusHydrationConfig))
+            {
+                return statusHydrationConfig;
+            }
+
+            return GVFSConstants.GitConfig.ShowHydrationStatusDefault;
+        }
     }
 }

GVFS/GVFS.Common/GVFSConstants.cs

@@ -42,6 +42,9 @@ public static class GitConfig
             /* Intended to be a temporary config to allow testing of distrusting pack indexes from cache server
              * before it is enabled by default. */
             public const string TrustPackIndexes = GVFSPrefix + "trust-pack-indexes";
+
+            public const string ShowHydrationStatus = GVFSPrefix + "show-hydration-status";
+            public const bool ShowHydrationStatusDefault = false;
         }
 
         public static class LocalGVFSConfig

GVFS/GVFS.Common/GitStatusCache.cs

@@ -52,7 +52,7 @@ public class GitStatusCache : IDisposable
 
         private object cacheFileLock = new object();
 
-        internal static bool TEST_EnableHydrationSummary = true;
+        internal static bool? TEST_EnableHydrationSummaryOverride = null;
 
         public GitStatusCache(GVFSContext context, GitStatusCacheConfig config)
             : this(context, config.BackoffTime)
@@ -341,7 +341,8 @@ private void RebuildStatusCacheIfNeeded(bool ignoreBackoff)
 
         private void UpdateHydrationSummary()
         {
-            if (!TEST_EnableHydrationSummary)
+            bool enabled = TEST_EnableHydrationSummaryOverride ?? this.context.Enlistment.GetStatusHydrationConfig();
+            if (!enabled)
             {
                 return;
             }

GVFS/GVFS.Common/HealthCalculator/EnlistmentHydrationSummary.cs

@@ -28,12 +28,12 @@ public string ToMessage()
         {
             if (!IsValid)
             {
-                return "Error calculating hydration. Run 'gvfs health' for details.";
+                return "Error calculating hydration summary. Run 'gvfs health' at the repository root for hydration status details.";
             }
 
             int fileHydrationPercent = TotalFileCount == 0 ? 0 : (100 * HydratedFileCount) / TotalFileCount;
             int folderHydrationPercent = TotalFolderCount == 0 ? 0 : ((100 * HydratedFolderCount) / TotalFolderCount);
-            return $"{fileHydrationPercent}% of files and {folderHydrationPercent}% of folders hydrated. Run 'gvfs health' for details.";
+            return $"{fileHydrationPercent}% of files and {folderHydrationPercent}% of folders hydrated. Run 'gvfs health' at the repository root for details.";
         }
 
         public static EnlistmentHydrationSummary CreateSummary(

GVFS/GVFS.Hooks/Program.cs

@@ -88,8 +88,9 @@ private static void RunPreCommands(string[] args)
                     ProcessHelper.Run("gvfs", "prefetch --commits", redirectOutput: false);
                     break;
                 case "status":
-                    /* If status is being run to serialize for caching, skip the health display */
-                    if (!args.Any(arg => arg.StartsWith("--serialize", StringComparison.OrdinalIgnoreCase)))
+                    /* If status is being run to serialize for caching, or if --porcelain is specified, skip the health display */
+                    if (!ArgsBlockHydrationStatus(args)
+                        && ConfigurationAllowsHydrationStatus())
                     {
                         /* Display a message about the hydration status of the repo */
                         ProcessHelper.Run("gvfs", "health --status", redirectOutput: false);
@@ -98,6 +99,30 @@ private static void RunPreCommands(string[] args)
             }
         }
 
+        private static bool ArgsBlockHydrationStatus(string[] args)
+        {
+            return args.Any(arg =>
+                arg.StartsWith("--serialize", StringComparison.OrdinalIgnoreCase)
+                || arg.StartsWith("--porcelain", StringComparison.OrdinalIgnoreCase));
+        }
+
+        private static bool ConfigurationAllowsHydrationStatus()
+        {
+            try
+            {
+                ProcessResult result = ProcessHelper.Run("git", $"config --get {GVFSConstants.GitConfig.ShowHydrationStatus}");
+                bool hydrationStatusEnabled;
+                if (bool.TryParse(result.Output.Trim(), out hydrationStatusEnabled))
+                {
+                    return hydrationStatusEnabled;
+                }
+            }
+            catch (Exception)
+            {
+            }
+            return GVFSConstants.GitConfig.ShowHydrationStatusDefault;
+        }
+
         private static void ExitWithError(params string[] messages)
         {
             foreach (string message in messages)

GVFS/GVFS.UnitTests/Common/GitStatusCacheTests.cs

@@ -73,7 +73,7 @@ public void SetUp()
                 this.fileSystem,
                 new MockGitRepo(tracer, enlistment, this.fileSystem),
                 enlistment);
-            GitStatusCache.TEST_EnableHydrationSummary = false;
+            GitStatusCache.TEST_EnableHydrationSummaryOverride = false;
         }
 
         [TearDown]
@@ -85,7 +85,7 @@ public void TearDown()
             this.gitParentPath = null;
             this.gvfsMetadataPath = null;
             this.enlistmentDirectory = null;
-            GitStatusCache.TEST_EnableHydrationSummary = true;
+            GitStatusCache.TEST_EnableHydrationSummaryOverride = null;
         }
 
         [TestCase]