Catch expected exceptions thrown by DirectoryHelper

ThomasBarnekow · ThomasBarnekow · commit 3afb1754e612 · 2015-02-23T17:24:04.000+01:00
The DirectoryHelper.DeleteDirectory() method throws exceptions. Affected tests will be reported as FAILED although this happens during cleanup after the test was run. This commit deals with those exceptions by retrying to delete the directory up to four times, which removes directories in all but rare cases. The method catches DirectoryNotFoundException, IOException, and UnauthorizedAccessException and will only log a trace message if it can't finally delete the directory. It will rethrow any other type of exception. Closes libgit2#970.
diff --git a/LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs b/LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs
@@ -156,7 +156,7 @@ public string SandboxAssumeUnchangedTestRepo()
         {
             return Sandbox(AssumeUnchangedRepoWorkingDirPath);
         }
-        
+
         public string SandboxSubmoduleSmallTestRepo()
         {
             var submoduleTarget = Path.Combine(ResourcesDirectory.FullName, "submodule_target_wd");
diff --git a/LibGit2Sharp.Tests/TestHelpers/DirectoryHelper.cs b/LibGit2Sharp.Tests/TestHelpers/DirectoryHelper.cs
@@ -2,6 +2,8 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
+using System.Threading;
 
 namespace LibGit2Sharp.Tests.TestHelpers
 {
@@ -47,40 +49,61 @@ public static void DeleteDirectory(string directoryPath)
 
             if (!Directory.Exists(directoryPath))
             {
-                Trace.WriteLine(
-                    string.Format("Directory '{0}' is missing and can't be removed.",
-                        directoryPath));
-
+                Trace.WriteLine(string.Format("Directory '{0}' is missing and can't be removed.", directoryPath));
                 return;
             }
+            NormalizeAttributes(directoryPath);
+            TryDeleteDirectory(directoryPath, 5, 16, 2);
+        }
 
+        private static void NormalizeAttributes(string directoryPath)
+        {
             string[] files = Directory.GetFiles(directoryPath);
             string[] dirs = Directory.GetDirectories(directoryPath);
 
             foreach (string file in files)
             {
                 File.SetAttributes(file, FileAttributes.Normal);
-                File.Delete(file);
             }
-
             foreach (string dir in dirs)
             {
-                DeleteDirectory(dir);
+                NormalizeAttributes(dir);
             }
-
             File.SetAttributes(directoryPath, FileAttributes.Normal);
-            try
-            {
-                Directory.Delete(directoryPath, false);
-            }
-            catch (IOException)
+        }
+
+        private static Type[] whitelist = new[] { typeof(DirectoryNotFoundException), typeof(IOException), typeof(UnauthorizedAccessException) };
+
+        private static void TryDeleteDirectory(string directoryPath, int maxAttempts, int initialTimeout, int timeoutFactor)
+        {
+            for (int attempt = 1; attempt <= maxAttempts; attempt++)
             {
-                Trace.WriteLine(string.Format("{0}The directory '{1}' could not be deleted!" +
-                                                    "{0}Most of the time, this is due to an external process accessing the files in the temporary repositories created during the test runs, and keeping a handle on the directory, thus preventing the deletion of those files." +
-                                                    "{0}Known and common causes include:" +
-                                                    "{0}- Windows Search Indexer (go to the Indexing Options, in the Windows Control Panel, and exclude the bin folder of LibGit2Sharp.Tests)" +
-                                                    "{0}- Antivirus (exclude the bin folder of LibGit2Sharp.Tests from the paths scanned by your real-time antivirus){0}",
-                    Environment.NewLine, Path.GetFullPath(directoryPath)));
+                try
+                {
+                    Directory.Delete(directoryPath, true);
+                    return;
+                }
+                catch (Exception ex)
+                {
+                    if (!whitelist.Contains(ex.GetType()))
+                    {
+                        throw;
+                    }
+
+                    if (attempt < maxAttempts)
+                    {
+                        Thread.Sleep(initialTimeout * (int)Math.Pow(timeoutFactor, attempt - 1));
+                        continue;
+                    }
+
+                    Trace.WriteLine(string.Format("{0}The directory '{1}' could not be deleted due to a {2}: {3}" +
+                                                  "{0}Most of the time, this is due to an external process accessing the files in the temporary repositories created during the test runs, and keeping a handle on the directory, thus preventing the deletion of those files." +
+                                                  "{0}Known and common causes include:" +
+                                                  "{0}- Windows Search Indexer (go to the Indexing Options, in the Windows Control Panel, and exclude the bin folder of LibGit2Sharp.Tests)" +
+                                                  "{0}- Antivirus (exclude the bin folder of LibGit2Sharp.Tests from the paths scanned by your real-time antivirus)" +
+                                                  "{0}- TortoiseGit (change the 'Icon Overlays' settings, e.g., adding the bin folder of LibGit2Sharp.Tests to 'Exclude paths' and appending an '*' to exclude all subfolders as well)",
+                        Environment.NewLine, Path.GetFullPath(directoryPath), ex.GetType(), ex.Message));
+                }
             }
         }
     }

Original file line number	Diff line number	Diff line change
`@@ -156,7 +156,7 @@ public string SandboxAssumeUnchangedTestRepo()`
`156`	`156`	`{`
`157`	`157`	`return Sandbox(AssumeUnchangedRepoWorkingDirPath);`
`158`	`158`	`}`
`159`		`-`
	`159`	`+`
`160`	`160`	`public string SandboxSubmoduleSmallTestRepo()`
`161`	`161`	`{`
`162`	`162`	`var submoduleTarget = Path.Combine(ResourcesDirectory.FullName, "submodule_target_wd");`