From b08b3de6707fd9ec2ce76343aac9e7721ed1e407 Mon Sep 17 00:00:00 2001
From: Davide Magrin <magrin.davide@gmail.com>
Date: Thu, 20 Dec 2018 14:39:39 +0100
Subject: [PATCH] Fix empty compile_commands.json

This commit re-enables the keep_last_cmd member variable in the TaskBase class
(which was disabled by default in Waf 2.0.9) when clang_compilation_database.py
is used. The clang_compilation_database.py file was correctly updated in the
relevant Waf commit introducing the change [1], but is missing in ns-3's bundled
version of Waf.

[1] https://gitlab.com/ita1024/waf/commit/7778868718333932708a3915825f5c3f4ac53341
---
 waf-tools/clang_compilation_database.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/waf-tools/clang_compilation_database.py b/waf-tools/clang_compilation_database.py
index a9e61ff07..53e637a20 100644
--- a/waf-tools/clang_compilation_database.py
+++ b/waf-tools/clang_compilation_database.py
@@ -15,9 +15,11 @@ Usage:
 """
 
 import sys, os, json, shlex, pipes
-from waflib import Logs, TaskGen
+from waflib import Logs, TaskGen, Task
 from waflib.Tools import c, cxx
 
+Task.TaskBase.keep_last_cmd = True
+
 if sys.hexversion >= 0x3030000:
 	quote = shlex.quote
 else: