fix(index): match AppMap metadata files by name, not JSON file type

On build 262 the AppMap indexes returned nothing, so metadata/name/classMap
lookups (and AppMap discovery) came up empty. Root cause: both the index
input filters and the appMapsWithExcluded search scope gated on
JsonFileType.INSTANCE, but JSON language support is provided by a separate
platform module whose file-type registration is not active in every runtime
(notably the 262 test sandbox). Files such as metadata.json were therefore
not classified as JSON, so a FileTypeSpecificInputFilter never offered them
to the indexer and getScopeRestrictedByFileTypes(..., JsonFileType) excluded
them from the query scope.

The files we index have specific, known names, so the JSON file type gate was
only ever an optimisation on top of an exact-name match. Replace the
FileTypeSpecificInputFilter with a plain FileBasedIndex.InputFilter that matches
by file name alone, and drop the JsonFileType restriction from
appMapsWithExcluded. The scope is only used to query our own name-matched
indexes and to locate *.appmap.json files by extension via the platform's
FilenameIndex, neither of which needs a file-type restriction.

Bump the shared index version (66 -> 67) to rebuild indexes once on upgrade.

Verified: the index tests and OpenRecentAppMapActionTest pass on both 251 and
262 (they failed on 262 before this change).

Assisted-by: Claude:claude-opus-4-8

Author: dividedmind

plugin-core/src/main/java/appland/index/AbstractAppMapMetadataFileIndex.java

@@ -1,7 +1,6 @@
 package appland.index;
 
 import com.google.gson.JsonParseException;
-import com.intellij.json.JsonFileType;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.util.indexing.FileBasedIndex;
 import com.intellij.util.indexing.FileContent;
@@ -20,9 +19,10 @@
 abstract class AbstractAppMapMetadataFileIndex<T> extends SingleEntryFileBasedIndexExtension<T> {
     private static final Logger LOG = Logger.getInstance(AbstractAppMapMetadataFileIndex.class);
 
-    private final FileBasedIndex.InputFilter inputFilter = new NamedFileTypeFilter(JsonFileType.INSTANCE, fileName -> {
-        return getIndexedFileName().equalsIgnoreCase(fileName);
-    });
+    // Match by file name only. We intentionally do not use a FileTypeSpecificInputFilter keyed on the
+    // JSON file type: JSON language support is a separate platform module whose file-type registration
+    // is not active in every runtime (e.g. the 262 test sandbox), which would silently exclude our files.
+    private final FileBasedIndex.InputFilter inputFilter = file -> getIndexedFileName().equalsIgnoreCase(file.getName());
 
     private final SingleEntryIndexer<T> indexer = new SingleEntryIndexer<>(false) {
         @Override

plugin-core/src/main/java/appland/index/AppMapSearchScopes.java

@@ -1,6 +1,5 @@
 package appland.index;
 
-import com.intellij.json.JsonFileType;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.roots.FileIndexFacade;
@@ -23,10 +22,14 @@ private AppMapSearchScopes() {
 
     /**
      * @param project Project
-     * @return Search scope, which contains all .appmap.json files of the project, included files inside excluded directories. The scope is also restricted by the JSON file type.
+     * @return Search scope, which contains all project files, including files inside excluded directories.
+     * The scope is intentionally not restricted by the JSON file type: it is used to query AppMap
+     * metadata indexes whose input filters already match the specific file names, and JSON language
+     * support is an optional platform module that may not classify {@code .json} files as JSON in every
+     * runtime.
      */
     public static @NotNull GlobalSearchScope appMapsWithExcluded(@NotNull Project project) {
-        return GlobalSearchScope.getScopeRestrictedByFileTypes(projectFilesWithExcluded(project), JsonFileType.INSTANCE);
+        return projectFilesWithExcluded(project);
     }
 
     public static @NotNull GlobalSearchScope appMapConfigSearchScope(@NotNull Project project) {

plugin-core/src/main/java/appland/index/ClassMapTypeIndex.java

@@ -1,7 +1,6 @@
 package appland.index;
 
 import appland.files.AppMapFiles;
-import com.intellij.json.JsonFileType;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.DumbService;
 import com.intellij.openapi.project.Project;
@@ -27,7 +26,8 @@
  */
 public class ClassMapTypeIndex extends FileBasedIndexExtension<ClassMapItemType, List<ClassMapItem>> {
     private static final ID<ClassMapItemType, List<ClassMapItem>> INDEX_ID = ID.create("appmap.classMap");
-    private static final FileBasedIndex.FileTypeSpecificInputFilter INPUT_FILTER = new NamedFileTypeFilter(JsonFileType.INSTANCE, ClassMapUtil.CLASS_MAP_FILE::equalsIgnoreCase);
+    // Match by file name only, not by JSON file type (see AbstractAppMapMetadataFileIndex).
+    private static final FileBasedIndex.InputFilter INPUT_FILTER = file -> ClassMapUtil.CLASS_MAP_FILE.equalsIgnoreCase(file.getName());
     private static final DataExternalizer<List<ClassMapItem>> DATA_EXTERNALIZER = new DataExternalizer<>() {
         @Override
         public void save(@NotNull DataOutput out, @NotNull List<ClassMapItem> values) throws IOException {

plugin-core/src/main/java/appland/index/IndexUtil.java

@@ -26,7 +26,8 @@
 
 final class IndexUtil {
     // base version for our indexes, increase when the data structures or the parsing logic change
-    static final int BASE_VERSION = 66;
+    // 67: input filters match by file name only, no longer gated on the JSON file type
+    static final int BASE_VERSION = 67;
 
     // filenames covered by our own indexes
     static final Set<String> indexedFilenames = Collections.unmodifiableSet(findIndexedFilenames());