From 28c405faa991eb8c20b641867ae06a8dc376f7ed Mon Sep 17 00:00:00 2001
From: azerr <azerr@redhat.com>
Date: Tue, 12 Sep 2023 14:54:38 +0200
Subject: [PATCH] fix: NPE in LSPIJUtils.editorForElement

Fixes #1156

Signed-off-by: azerr <azerr@redhat.com>
---
 .../devtools/intellij/lsp4ij/LSPIJUtils.java  |  4 +--
 .../LSPDocumentationProvider.java             | 29 ++++++++++++++-----
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/redhat/devtools/intellij/lsp4ij/LSPIJUtils.java b/src/main/java/com/redhat/devtools/intellij/lsp4ij/LSPIJUtils.java
index f3edb724c..ee59687d8 100644
--- a/src/main/java/com/redhat/devtools/intellij/lsp4ij/LSPIJUtils.java
+++ b/src/main/java/com/redhat/devtools/intellij/lsp4ij/LSPIJUtils.java
@@ -428,8 +428,8 @@ public static Editor editorForFile(VirtualFile file) {
         return editors.length > 0 ? editors[0] : null;
     }
 
-    public static Editor editorForElement(PsiElement element) {
-        if (element.getContainingFile() != null && element.getContainingFile().getVirtualFile() != null) {
+    public static Editor editorForElement(@Nullable PsiElement element) {
+        if (element != null && element.getContainingFile() != null && element.getContainingFile().getVirtualFile() != null) {
             return editorForFile(element.getContainingFile().getVirtualFile());
         }
         return null;
diff --git a/src/main/java/com/redhat/devtools/intellij/lsp4ij/operations/documentation/LSPDocumentationProvider.java b/src/main/java/com/redhat/devtools/intellij/lsp4ij/operations/documentation/LSPDocumentationProvider.java
index ffb9804c1..1aba08130 100644
--- a/src/main/java/com/redhat/devtools/intellij/lsp4ij/operations/documentation/LSPDocumentationProvider.java
+++ b/src/main/java/com/redhat/devtools/intellij/lsp4ij/operations/documentation/LSPDocumentationProvider.java
@@ -66,21 +66,36 @@ public String getQuickNavigateInfo(PsiElement element, PsiElement originalElemen
 
     @Nullable
     @Override
-    public String generateDoc(PsiElement element, @Nullable PsiElement originalElement) {
+    public String generateDoc(@NotNull PsiElement element, @Nullable PsiElement originalElement) {
         try {
             Project project = element.getProject();
             if (project.isDisposed()) {
                 return null;
             }
-            Editor editor = LSPIJUtils.editorForElement(element);
-            if (editor == null) {
-                return null;
+            Editor editor = null;
+            List<MarkupContent> markupContent = null;
+            if (element instanceof LSPPsiElementForLookupItem) {
+                // Show documentation for a given completion item in the "documentation popup" (see IJ Completion setting)
+                // (LSP textDocument/completion request)
+                editor = LSPIJUtils.editorForElement(element);
+                markupContent = ((LSPPsiElementForLookupItem) element).getDocumentation();
+            } else {
+                // Show documentation for a hovered element (LSP textDocument/hover request).
+                if (originalElement == null) {
+                    return null;
+                }
+                editor = LSPIJUtils.editorForElement(originalElement);
+                VirtualFile file = originalElement.getContainingFile().getVirtualFile();
+                if (LSPVirtualFileWrapper.hasWrapper(file)) {
+                    int targetOffset = getTargetOffset(originalElement);
+                    markupContent = LSPVirtualFileWrapper.getLSPVirtualFileWrapper(file).getHoverContent(originalElement, targetOffset, editor);
+                }
             }
-            List<MarkupContent> result = getMarkupContents(element, originalElement);
-            if (result == null || result.isEmpty()) {
+
+            if (editor == null || markupContent == null || markupContent.isEmpty()) {
                 return null;
             }
-            String s = result
+            String s = markupContent
                     .stream()
                     .map(m -> m.getValue())
                     .collect(Collectors.joining("\n\n"));