From 0487ea9f642c0e460785db5dc04664b4fb0988f0 Mon Sep 17 00:00:00 2001
From: Thiago de Arruda <tpadilha84@gmail.com>
Date: Mon, 13 Apr 2015 09:51:33 -0300
Subject: [PATCH] build: Improve GenerateHelptags.cmake failure message

Some errors during helptags can be caused by duplicate/wrong tags after
documentation cleanup. Suggest the removal of the "doc" directory.
---
 cmake/GenerateHelptags.cmake | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/cmake/GenerateHelptags.cmake b/cmake/GenerateHelptags.cmake
index 658f4ab9cc..d4f4518b9b 100644
--- a/cmake/GenerateHelptags.cmake
+++ b/cmake/GenerateHelptags.cmake
@@ -9,6 +9,12 @@ else()
 endif()
 
 message(STATUS "Generating helptags in ${HELPTAGS_WORKING_DIRECTORY}.")
+if(EXISTS "${HELPTAGS_WORKING_DIRECTORY}/")
+  message(STATUS "${HELPTAGS_WORKING_DIRECTORY} already exists")
+  # if the doc directory already exists, helptags could fail due to duplicate
+  # tags. Tell the user to remove the directory and try again.
+  set(TROUBLESHOOTING "\nRemove \"${HELPTAGS_WORKING_DIRECTORY}\" and try again")
+endif()
 
 execute_process(
   COMMAND "${CMAKE_CURRENT_BINARY_DIR}/bin/nvim"
@@ -22,5 +28,5 @@ execute_process(
   RESULT_VARIABLE res)
 
 if(NOT res EQUAL 0)
-  message(FATAL_ERROR "Generating helptags failed: ${err} - ${res}")
+  message(FATAL_ERROR "Generating helptags failed: ${err} - ${res}${TROUBLESHOOTING}")
 endif()