Dto Generation is broken for Formatter Options

[svor]

After applying code format (Edit -> Format or Alt+Shift+L) have an error

SEVERE: Unknown DTO type class org.eclipse.lsp4j.FormattingOptions
java.lang.IllegalArgumentException: Unknown DTO type class org.eclipse.lsp4j.FormattingOptions
	at Unknown.Xo(Throwable.java:66)
	at Unknown.ep(Exception.java:29)
	at Unknown.ip(RuntimeException.java:29)
	at Unknown.yYd(IllegalArgumentException.java:29)
	at Unknown.T2g(DtoFactory.java:113)
	at Unknown.Yfl(DtoFactory.java:38)
	at Unknown._fl(LanguageServerFormatter.java:137)
	at Unknown.O9g(OrionEditorPresenter.java:949)
	at Unknown.x5e(FormatterAction.java:55)
	at Unknown.Wvk(PopupMenu.java:562)
	at Unknown.jwk(PopupMenu.java:719)
	at Unknown.FBd(DOM.java:1481)
	at Unknown.iDd(DOMImplStandard.java:317)
	at Unknown._p(Impl.java:309)
	at Unknown.cq(Impl.java:361)
	at Unknown.anonymous(Impl.java:78)
	at Unknown.bC(StringValidator.java:66)
	at Unknown.aC(StringValidator.java:49)
	at Unknown.OB(RequestBuilder.java:292)
	at Unknown.VMk(AsyncRequest.java:72)
	at Unknown.ZMk(MachineAsyncRequestFactory.java:129)
	at Unknown.anonymous(JsPromise.java:116)
	at Unknown.Vll(OccurrencesProvider.java:92)
	at Unknown.Xll(OccurrencesProvider.java:85)
	at Unknown.anonymous(JsPromise.java:68)
	at Unknown.bC(StringValidator.java:66)
	at Unknown.aC(StringValidator.java:49)
	at Unknown.OB(RequestBuilder.java:292)
	at Unknown.VMk(AsyncRequest.java:72)
	at Unknown.ZMk(MachineAsyncRequestFactory.java:129)
	at Unknown.anonymous(JsPromise.java:116)
	at Unknown.Vll(OccurrencesProvider.java:92)
	at Unknown.Xll(OccurrencesProvider.java:85)
	at Unknown.anonymous(JsPromise.java:68)
	at Unknown.bC(StringValidator.java:66)
	at Unknown.aC(StringValidator.java:49)
	at Unknown.OB(RequestBuilder.java:292)
	at Unknown.VMk(AsyncRequest.java:72)
	at Unknown.ZMk(MachineAsyncRequestFactory.java:129)
	at Unknown.anonymous(JsPromise.java:116)
	at Unknown.bC(StringValidator.java:66)
	at Unknown.aC(StringValidator.java:49)
	at Unknown.OB(RequestBuilder.java:292)
	at Unknown.VMk(AsyncRequest.java:72)
	at Unknown.ZMk(MachineAsyncRequestFactory.java:129)
	at Unknown.anonymous(JsPromise.java:116)
	at Unknown.Vll(OccurrencesProvider.java:92)
	at Unknown.Xll(OccurrencesProvider.java:85)
	at Unknown.anonymous(JsPromise.java:68)
	at Unknown.Vll(OccurrencesProvider.java:92)
	at Unknown.Xll(OccurrencesProvider.java:85)
	at Unknown.anonymous(JsPromise.java:68)
	at Unknown.Vll(OccurrencesProvider.java:92)
	at Unknown.Xll(OccurrencesProvider.java:85)
	at Unknown.anonymous(JsPromise.java:68)

[jonahgraham]

The problem is the LSP4J changed FormattingOptions to be a Map.

Therefore first problem is that org.eclipse.che.api.languageserver.generator.DtoGenerator.generate(File, String, String, String[], String[]) excludes FormattingOptions because its class hierarchy contains LinkedHashMap which is not in one of the listed packages.

You can work around the first problem by doing:

diff --git a/plugins/plugin-languageserver/che-plugin-languageserver-ide/pom.xml b/plugins/plugin-languageserver/che-plugin-languageserver-ide/pom.xml
index e97c25e998..682302578f 100644
--- a/plugins/plugin-languageserver/che-plugin-languageserver-ide/pom.xml
+++ b/plugins/plugin-languageserver/che-plugin-languageserver-ide/pom.xml
@@ -222,6 +222,9 @@
                         <package>org.eclipse.che.api.languageserver.shared.event</package>
                         <package>org.eclipse.che.api.languageserver.shared.model</package>
                     </dtoPackages>
+                    <classes>
+                        <class>org.eclipse.lsp4j.FormattingOptions</class>
+                    </classes>
                     <outputDirectory>${dto-generator-out-directory}</outputDirectory>
                     <genClassName>org.eclipse.che.api.languageserver.shared.dto.DtoClientImpls</genClassName>
                     <impl>client</impl>

which forces the Dto generation to happen and I suppose is there for this kind of situation. But then you hit the second problem.

The second problem is possibly just cosmetic, I am not sure. But the to/from JSON in the generated FormattingOptions does not look like it will work because it will try to create a JSON object from an Either3 directly. This means updating the generator to support this new LSP4J use case.

The simpler option

The alternative solution is to simply not use a Dto for FormattingOptions at all. As FormattingOptions is never used as a LS parameter directly and always used as a field in other types (e.g. DocumentOnTypeFormattingParams.setOptions) then you could just do this because the to/fromJSon of the containing types don't delegate to FormattingOptions and rather handle the FormattingOptions as a Map.

diff --git a/plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/editor/LanguageServerFormatter.java b/plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/editor/LanguageServerFormatter.java
index fe0c8f92e6..1ae5904947 100644
--- a/plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/editor/LanguageServerFormatter.java
+++ b/plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/editor/LanguageServerFormatter.java
@@ -188,7 +188,7 @@ public class LanguageServerFormatter implements ContentFormatter {
   }
 
   private FormattingOptions getFormattingOptions() {
-    FormattingOptions options = dtoFactory.createDto(FormattingOptions.class);
+    FormattingOptions options = new FormattingOptions();
     options.setInsertSpaces(Boolean.parseBoolean(getEditorProperty(EditorProperties.EXPAND_TAB)));
     options.setTabSize(Integer.parseInt(getEditorProperty(EditorProperties.TAB_SIZE)));
     return options;

I'll submit a PR with the second solution.