Adds info about deprecated extensions to VSCode client API

server/src/main/java/org/eclipse/openvsx/adapter/ExtensionQueryResult.java

@@ -41,7 +41,7 @@ public record Extension(
             @Schema(description = "Date and time when this extension was last updated (ISO-8601)")
             String lastUpdated,
             List<String> categories,
-            @Schema(description = "Flag extension as preview")
+            @Schema(description = "Flag extension as preview or deprecated (e.g., 'preview,deprecated', 'preview', 'deprecated')")
             String flags
     ) {
         public static final String FLAG_PREVIEW = "preview";

server/src/main/java/org/eclipse/openvsx/adapter/LocalVSCodeService.java

@@ -548,4 +548,46 @@ private boolean isWebExtension(ExtensionVersion extVer) {
     private boolean test(int flags, int flag) {
         return (flags & flag) != 0;
     }
+
+    /**
+     * Build a VS Code Extensions Control Manifest (partial) containing only the `deprecated` dictionary.
+     * The dictionary maps extension id (publisher.name) to either `true` or an object with optional fields
+     * such as `disallowInstall` and `extension` (replacement recommendation), per IRawExtensionsControlManifest.
+     */
+    public Map<String, Object> buildExtensionsControlManifestDeprecated() {
+        var deprecatedMap = new LinkedHashMap<String, Object>();
+
+        for (var ext : repositories.findAllActiveExtensions()) {
+            if (!ext.isDeprecated()) {
+                continue;
+            }
+
+            var extensionId = ext.getNamespace().getName() + "." + ext.getName();
+
+            var details = new LinkedHashMap<String, Object>();
+
+            if (ext.getDownloadable() != null && !ext.getDownloadable()) {
+                details.put("disallowInstall", true);
+            }
+
+            var replacement = ext.getReplacement();
+            if (replacement != null) {
+                var latestReplacement = repositories.findLatestVersion(replacement, null, false, true);
+                var replacementDisplayName = latestReplacement != null ? latestReplacement.getDisplayName() : replacement.getName();
+                var replacementId = replacement.getNamespace().getName() + "." + replacement.getName();
+                details.put("extension", Map.of(
+                        "id", replacementId,
+                        "displayName", replacementDisplayName
+                ));
+            }
+
+            if (details.isEmpty()) {
+                deprecatedMap.put(extensionId, Boolean.TRUE);
+            } else {
+                deprecatedMap.put(extensionId, details);
+            }
+        }
+
+        return deprecatedMap;
+    }
 }

server/src/main/java/org/eclipse/openvsx/adapter/VSCodeAPI.java

@@ -32,6 +32,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 import static org.eclipse.openvsx.adapter.ExtensionQueryParam.*;
 import static org.eclipse.openvsx.adapter.ExtensionQueryResult.ExtensionFile.*;
@@ -88,6 +89,21 @@ public ExtensionQueryResult extensionQuery(@RequestBody @Parameter(description =
         return extensionQueryRequestHandler.getResult(param, size, DEFAULT_PAGE_SIZE);
     }
 
+    @GetMapping(
+            path = "/vscode/gallery/extensioncontrol",
+            produces = MediaType.APPLICATION_JSON_VALUE
+    )
+    @CrossOrigin
+    @Operation(summary = "Provides VS Code Extensions Control manifest (partial) containing 'deprecated' mapping")
+    @ApiResponse(
+            responseCode = "200",
+            description = "Returns the control manifest"
+    )
+    public Map<String, Object> getExtensionsControlManifest() {
+        // Only provide the deprecated dictionary for now
+        return Map.of("deprecated", local.buildExtensionsControlManifestDeprecated());
+    }
+
     @Observed
     @GetMapping("/vscode/asset/{namespaceName}/{extensionName}/{version}/{assetType}/**")
     @CrossOrigin