Build error

[lePereT]

Hi all, I'm getting an error from CMake in my attempt to build a recent version of luv for OpenWrt.

Essentially I'm using the makefile here: https://github.com/openwrt/packages/blob/master/lang/luv/Makefile and amending the version number and hash to 1.36 or 1.34. Whereas 1.22 builds, more recent version builds fail with this message:

CMake Error at /home/ubuntu/wrtbuilder/openwrt/staging_dir/host/share/cmake-3.11/Modules/FindPackageHandleStandardArgs.cmake:137 (message):
  Could NOT find Lua (missing: LUA_INCLUDE_DIR)
Call Stack (most recent call first):
  /home/ubuntu/wrtbuilder/openwrt/staging_dir/host/share/cmake-3.11/Modules/FindPackageHandleStandardArgs.cmake:378 (_FPHSA_FAILURE_MESSAGE)
  /home/ubuntu/wrtbuilder/openwrt/staging_dir/host/share/cmake-3.11/Modules/FindLua.cmake:193 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:111 (find_package)

Is there something basic that I'm doing wrong? Or has something changed between 1.22 and 1.34+ that I need to incorporate. Libuv appears to building fine.

Thanks!

[squeek502]

The find_package(Lua) changed to use REQUIRED in 1a70120

This might have been a mistake, since presumably it's failing to find the libraries, not the headers, and we only actually link against the libraries on Windows. So, the REQUIRED should probably be removed for find_package(Lua) on non-Windows.

[lePereT]

Thanks for this squeek502. I've tried rebuilding with your patch applied atop 1.36.0 and voila, a slightly different error:

-- Could NOT find Lua (missing: LUA_INCLUDE_DIR)
CMake Error at CMakeLists.txt:128 (message):
  Failed to find Lua headers.  Variable `LUA_INCLUDE_DIR' expected to be
  defined.

(Using Ubuntu 18.04 x64 to build with lua 5.1 and libdevellua 5.1 and luarocks all installed)

[squeek502]

Could you try the following patch:

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 357d7f6..9b7ff1d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,9 +112,6 @@ else (LUA)
       else()
         find_package(LuaJIT)
       endif()
-      if(NOT LUAJIT_INCLUDE_DIR)
-        message( FATAL_ERROR "Failed to find LuaJIT headers. Variable `LUAJIT_INCLUDE_DIR' expected to be defined.")
-      endif()
       include_directories(${LUAJIT_INCLUDE_DIR})
     else (USE_LUAJIT)
       # We only link the libs on Windows, so find_package fully succeeding
@@ -124,9 +121,6 @@ else (LUA)
       else()
         find_package(Lua)
       endif()
-      if(NOT LUA_INCLUDE_DIR)
-        message( FATAL_ERROR "Failed to find Lua headers. Variable `LUA_INCLUDE_DIR' expected to be defined.")
-      endif()
       include_directories(${LUA_INCLUDE_DIR})
     endif (USE_LUAJIT)

I expect it to fail to find the headers at compile time, but if it doesn't, then that's worth knowing, as it means something stranger is going on.

[lePereT]

as you suspected, it fails to find the headers:

/home/ubuntu/wrtbuilder/openwrt/build_dir/target-mips_24kc_musl/luv-1.36.0-0-rt1/src/luv.c:20:10: fatal error: compat-5.3.h: No such file or directory
 #include "compat-5.3.h"

so i'm glad those checks are working! am i missing an obvious package?

$ apt list --installed | grep lua

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

liblua5.1-0/bionic,now 5.1.5-8.1build2 amd64 [installed]
liblua5.1-0-dbg/bionic,now 5.1.5-8.1build2 amd64 [installed]
liblua5.1-0-dev/bionic,now 5.1.5-8.1build2 amd64 [installed]
liblua5.2-0/bionic,now 5.2.4-1.1build1 amd64 [installed,automatic]
liblua5.3-0/bionic-updates,bionic-security,now 5.3.3-1ubuntu0.18.04.1 amd64 [installed,automatic]
liblua5.3-dev/bionic-updates,bionic-security,now 5.3.3-1ubuntu0.18.04.1 amd64 [installed]
lua-any/bionic,now 24 all [installed,automatic]
lua-compat53/bionic,now 0.3-3 amd64 [installed]
lua-sec/bionic,now 0.6-4 amd64 [installed]
lua-socket/bionic,now 3.0~rc1+git+ac3201d-4 amd64 [installed,automatic]
lua5.1/bionic,now 5.1.5-8.1build2 amd64 [installed]
luarocks/bionic,now 2.4.2+dfsg-1 all [installed]

[squeek502]

That is not the header I expected it not to be able to find (I was expecting lua.h or some other Lua header). We provide compat-5.3.h in our release tarball, and add its directory to the include paths here:

luv/CMakeLists.txt

Lines 160 to 166 in 9054ac8

	if(NOT LUA_COMPAT53_DIR)
	set(LUA_COMPAT53_DIR deps/lua-compat-5.3)
	endif()
	if(DEFINED ENV{LUA_COMPAT53_DIR})
	set(LUA_COMPAT53_DIR $ENV{LUA_COMPAT53_DIR})
	endif()
	include_directories(${LUA_COMPAT53_DIR}/c-api)

so I'm not really sure how its failing to find that...

[lePereT]

I made a mistake with the packaging and lost lua-compat-5.3 my bad!

When I fixed, interestingly, the combination of your small patch on top of your pull request builds flawlessly, and leads to a working build:

root@OpenWrt:~# lua helloworld.lua 
Now quitting.
root@OpenWrt:~# 

The pull request by itself fails to build.

[squeek502]

Strange, that means that CMake's FindLua.cmake is failing to find the Lua headers but your C compiler is succeeding. Do you know the path of the lua.h that is being used?

[rphillips]

Does the following fix it?

  if(NOT LUA_COMPAT53_DIR)
    set(LUA_COMPAT53_DIR ${CMAKE_SOURCE_DIR}/deps/lua-compat-5.3)
  endif()

[squeek502]

Re-opening this because, while I think #489 is the correct fix for what I understand the problem to be, I still want to investigate what's going on here since #489 won't fix @lePereT's problem without the patch in #488 (comment), but that patch shouldn't be necessary. I want to try to understand how CMake can fail to find the Lua headers while the C compiler succeeds.

EDIT: @lePereT's could you answer this?

Do you know the path of the lua.h that is being used?

[lePereT]

Hi Squeek, could you tell me how I might do that? Simply look for lua.h on the Ubuntu build server?

[squeek502]

The best place to look would be the CMakeFiles/libluv.dir/depend.make generated in your CMake build directory and look for a line like CMakeFiles/libluv.dir/src/luv.c.o: /usr/include/lua5.1/lua.h.

EDIT: On second thought, the above probably won't have a lua.h since the problem is that CMake is unable to find the path to lua.h 🤔.

If you can't find that, then try:

ls -d /usr/include/*/lua.h
ls -d /usr/include/lua*
ls -d /usr/local/include/*/lua.h
ls -d /usr/local/include/lua*