[vfs][refactoring] redefine BatchingFileSystem contract: always return case-sensitive maps

... thus it is responsibility of a caller to convert returned map to case-insensitive, if needed, and deal with possible inconsistencies during that conversion

GitOrigin-RevId: 83b2c714a4e9cba62281d2bf2a05ebd04f643225

platform/analysis-api/src/com/intellij/openapi/vfs/newvfs/ArchiveFileSystem.java

@@ -165,10 +165,11 @@ public abstract class ArchiveFileSystem extends NewVirtualFileSystem implements
 
     ArchiveHandler handler = getHandler(dir);
     if (childNames == null) {
-      childNames = createFilePathSet(handler.list(directoryRelativePath), isCaseSensitive());
+      childNames = createFilePathSet(handler.list(directoryRelativePath), /*isCaseSensitive: */ true);
     }
 
-    Map<String, FileAttributes> childrenWithAttributes = createFilePathMap(childNames.size(), isCaseSensitive());
+    //We must return 'normal' (case-sensitive) map from this method, see BatchingFileSystem.listWithAttributes() contract:
+    Map<String, FileAttributes> childrenWithAttributes = createFilePathMap(childNames.size(), /*isCaseSensitive: */ true);
 
     for (String childName : childNames) {
       String childRelativePath = normalizedDirectoryPath + childName;

platform/analysis-api/src/com/intellij/openapi/vfs/newvfs/persistent/BatchingFileSystem.java

@@ -18,12 +18,20 @@ import java.util.Set;
 @ApiStatus.Internal
 public interface BatchingFileSystem {
   /**
-   * Returns a list of files in a directory along with their attributes.
-   * When the {@code childrenNames} set is {@code null}, all files should be returned.
-   * TODO RC: specify, should returned map be case-(in)sensitive, according to dir.isCaseSensitive(), or it should be a plain
-   *          case-sensitive map, and it is up to client code to transform it, if needed?
+   * @return directory's children, in form of Map[childName-> FileAttributes]
+   * When the {@code childrenNames} is not-null, only those children's data should be returned (if exists!),
+   * when {@code childrenNames} is null -> all directory's children should be returned.
+   * Returned map should be a 'normal' (i.e., case-sensitive) map -- it is up to calling code to covert it to case-insensitive, if
+   * needed.
    */
-  @NotNull Map<@NotNull String, @NotNull FileAttributes> listWithAttributes(@NotNull VirtualFile dir, @Nullable Set<String> childrenNames);
+  //Why contract defines returned map to be case-sensitive? Because dir.isCaseSensitive() is tricky, and sometimes it's value could
+  // be unreliable/outdated -- in which case this method would provide incorrect info, be it defined to return map with case-sensitivity
+  // =dir.isCaseSensitive().
+  // But the responsibility of (Batching)FileSystem is _only_ to be golden-source of info about actual file system state -- it is
+  // the responsibility of the caller (=VFS) to deal with (possible) inconsistencies between VFS state and actual FS state.
+  //MAYBE RC: return List<Pair<String,FileAttributes>>? this way question of case-sensitivity is not even on the table
+  @NotNull Map<@NotNull String, @NotNull FileAttributes> listWithAttributes(@NotNull VirtualFile dir,
+                                                                            @Nullable Set<String> childrenNames);
 
   default @NotNull Map<@NotNull String, @NotNull FileAttributes> listWithAttributes(@NotNull VirtualFile dir) {
     return listWithAttributes(dir, null);

platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java

@@ -372,7 +372,8 @@ public class LocalFileSystemImpl extends LocalFileSystemBase implements Disposab
       return Collections.emptyMap();
     }
     try {
-      Map<String, FileAttributes> childrenWithAttributes = createFilePathMap(10, dir.isCaseSensitive());
+      //We must return 'normal' (case-sensitive) map from this method, see BatchingFileSystem.listWithAttributes() contract:
+      Map<String, FileAttributes> childrenWithAttributes = createFilePathMap(10, /*caseSensitive: */true);
 
       PlatformNioHelper.visitDirectory(Path.of(toIoPath(dir)), filter, (file, ioAttributesHolder) -> {
         try {

platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/RefreshWorker.java

@@ -255,6 +255,11 @@ final class RefreshWorker {
       for (String name : childrenNames) {
         childrenWithAttributes.put(name, null);
       }
+      if(childrenWithAttributes.size()!=childrenNames.length){
+        //TODO RC: seems like dir.isCaseSensitive() is wrong/outdated (i.e. actual dir case-sensitivity is different from
+        //         FS-default, and it wasn't yet determined).
+        //         We should re-query dir.case-sensitivity
+      }
     }
     myIoTime.addAndGet(System.nanoTime() - t);
 
@@ -401,15 +406,23 @@ final class RefreshWorker {
   }
 
   /** Converts a case-sensitive rawDirList map into case-insensitive, if toCaseSensitive=false, leaves the map as-is otherwise */
-  private static @NotNull Map<String, FileAttributes> adjustCaseSensitivity(@NotNull Map<String, FileAttributes> rawDirList,
+  private static @NotNull Map<String, FileAttributes> adjustCaseSensitivity(@NotNull Map<String, FileAttributes> childrenWithAttributes,
                                                                             boolean toCaseSensitive) {
     if (toCaseSensitive) {
-      return rawDirList;
+      return childrenWithAttributes;
     }
     else {
-      Map<String, FileAttributes> filtered = createFilePathMap(rawDirList.size(), /*caseSensitive: */ false);
-      filtered.putAll(rawDirList);
-      return filtered;
+      Map<String, FileAttributes> childrenWithAttributesCaseInsensitive = createFilePathMap(
+        childrenWithAttributes.size(),
+        /*caseSensitive: */ false
+      );
+      childrenWithAttributesCaseInsensitive.putAll(childrenWithAttributes);
+      if (childrenWithAttributesCaseInsensitive.size() != childrenWithAttributes.size()) {
+        //TODO RC: seems like a conflict if dir.isCaseSensitive() is wrong/outdated (i.e. actual dir case-sensitivity
+        //         is different from FS-default, and it wasn't yet determined).
+        //         We should re-query dir.case-sensitivity
+      }
+      return childrenWithAttributesCaseInsensitive;
     }
   }
 

platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/persistent/PersistentFSImpl.java

@@ -456,6 +456,7 @@ public final class PersistentFSImpl extends PersistentFS implements Disposable {
 
       //TODO RC: we use a map here to prevent duplicates -- but we still add those duplicates to childrenToAdd
       //         -- what's the point?
+      //MAYBE RC: duplicates may indicate wrongly-detected dir.caseSensitivity -- so we should consider re-detect it?
       ChildInfo newChild = justCreated.computeIfAbsent(
         newChildName,
         _newChildName -> makeChildRecord(dir, dirId, _newChildName, childData, fs, null)