Fix ProjectImports.zip regression from shared FileUtilities statics

src/Build.UnitTests/BinaryLogger_Tests.cs

@@ -542,6 +542,39 @@ public void BinaryLoggerShouldNotThrowWhenMetadataCannotBeExpanded()
             ObjectModelHelpers.BuildProjectExpectSuccess(project, binaryLogger);
         }
 
+        /// <summary>
+        /// Regression test for dotnet/dotnet#5433 — ClearCacheDirectory must not destroy the
+        /// ProjectImports archive before it is embedded in the binlog.
+        /// </summary>
+        [Fact]
+        public void BinlogEmbeddedImportsSurviveClearCacheDirectory()
+        {
+            string logFilePath = Path.Combine(_env.DefaultTestDirectory.Path, "test.binlog");
+
+            var collector = new ProjectImportsCollector(logFilePath, createFile: false, runOnBackground: false);
+            collector.AddFileFromMemory("testfile.proj", "<Project />");
+
+            // This is what XMake.cs does after EndBuild — wipes the cache directory.
+            FileUtilities.ClearCacheDirectory();
+
+            // ProcessResult must still read the archive after the cache dir is gone.
+            bool archiveRead = false;
+            collector.ProcessResult(
+                stream =>
+                {
+                    stream.Length.ShouldBeGreaterThan(0);
+                    archiveRead = true;
+                },
+                error => throw new InvalidOperationException(error));
+            archiveRead.ShouldBeTrue("Archive must be readable after ClearCacheDirectory");
+
+            // DeleteArchive must not throw (directory must still exist).
+            collector.DeleteArchive();
+
+            // Satisfy the fixture's expectation that _logFile exists.
+            File.WriteAllText(_logFile, string.Empty);
+        }
+
         /// <summary>
         /// Regression test for https://github.com/dotnet/msbuild/issues/6323.
         /// </summary>

src/Build/Logging/BinaryLogger/ProjectImportsCollector.cs

@@ -63,15 +63,12 @@ public ProjectImportsCollector(
             }
             else
             {
-                string cacheDirectory = FileUtilities.GetCacheDirectory();
-                if (!FileSystems.Default.DirectoryExists(cacheDirectory))
-                {
-                    Directory.CreateDirectory(cacheDirectory);
-                }
+                // Store the temporary archive in TempFileDirectory rather than GetCacheDirectory()
+                // because ClearCacheDirectory() wipes the cache dir during build shutdown.
+                string tempDirectory = FileUtilities.TempFileDirectory;
 
-                // Archive file will be temporarily stored in MSBuild cache folder and deleted when no longer needed
                 _archiveFilePath = Path.Combine(
-                    cacheDirectory,
+                    tempDirectory,
                     GetArchiveFilePath(
                         Path.GetFileName(logFilePath),
                         sourcesArchiveExtension));
@@ -304,7 +301,9 @@ public void Close()
         public void DeleteArchive()
         {
             Close();
-            File.Delete(_archiveFilePath);
+
+            // Best effort — the archive may already have been cleaned up.
+            FileUtilities.DeleteNoThrow(_archiveFilePath);
         }
     }
 }