From 153dd2fe0bf5be124b7bd70e45186691920c3e94 Mon Sep 17 00:00:00 2001
From: Christian Kandeler <christian.kandeler@qt.io>
Date: Tue, 23 Nov 2021 18:02:41 +0100
Subject: [PATCH] ClangCodeModel: Fix overly simplistic check

... when doing function call completion with clangd.
We did not take default arguments into account. E.g. the following
declaration:
    void func(int i, int j = int());
was mis-detected as taking no arguments, causing to the cursor to be at
the wrong location afterwards.

Change-Id: I522921721b0cb347ed593c43ed285ca6d02ccfee
Reviewed-by: David Schulz <david.schulz@qt.io>
---
 src/plugins/clangcodemodel/clangdclient.cpp | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/plugins/clangcodemodel/clangdclient.cpp b/src/plugins/clangcodemodel/clangdclient.cpp
index 7ca82cf1a8d..68a94b1fea9 100644
--- a/src/plugins/clangcodemodel/clangdclient.cpp
+++ b/src/plugins/clangcodemodel/clangdclient.cpp
@@ -2938,10 +2938,12 @@ void ClangdCompletionItem::apply(TextDocumentManipulatorInterface &manipulator,
     if (!edit)
         return;
 
+    const int labelOpenParenOffset = item.label().indexOf('(');
+    const int labelClosingParenOffset = item.label().indexOf(')');
     const auto kind = static_cast<CompletionItemKind::Kind>(
                 item.kind().value_or(CompletionItemKind::Text));
-    const bool isMacroCall = kind == CompletionItemKind::Text && item.label().contains('(')
-            && item.label().contains(')'); // Heuristic
+    const bool isMacroCall = kind == CompletionItemKind::Text && labelOpenParenOffset != -1
+            && labelClosingParenOffset > labelOpenParenOffset; // Heuristic
     const bool isFunctionLike = kind == CompletionItemKind::Function
             || kind == CompletionItemKind::Method || kind == CompletionItemKind::Constructor
             || isMacroCall;
@@ -2951,10 +2953,12 @@ void ClangdCompletionItem::apply(TextDocumentManipulatorInterface &manipulator,
     // Some preparation for our magic involving (non-)insertion of parentheses and
     // cursor placement.
     if (isFunctionLike && !rawInsertText.contains('(')) {
-        if (item.label().contains("()"))     // function takes no arguments
-            rawInsertText += "()";
-        else if (item.label().contains('(')) // function takes arguments
-            rawInsertText += "( )";
+        if (labelOpenParenOffset != -1) {
+            if (labelClosingParenOffset == labelOpenParenOffset + 1) // function takes no arguments
+                rawInsertText += "()";
+            else                                                     // function takes arguments
+                rawInsertText += "( )";
+        }
     }
 
     const int firstParenOffset = rawInsertText.indexOf('(');