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0015116

CMake

public

2014-08-29 13:11

2015-11-02 09:13

Reporter

Vijay Pradeep

Assigned To

Brad King

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

Linux

Ubuntu

OS Version

12.04

Product Version

CMake 2.8.12.2

Target Version

CMake 3.2.1

Fixed in Version

CMake 3.2.1

Summary

0015116: cmake add_custom_command issue with multiple output files

Description

I'm noticing some potential incorrect behavior in cmake when working with add_custom_command and multiple output files. I've been able to isolate the problem to a minimal example (see below). It seems that when I have two output files specified in my add_custom_command, the second output file's upstream dependencies are not being tracked correctly in some cases. The cmake documentation clearly mentions that multiple output files are allowed. What's interesting here is that swapping the order of the output files causes different behavior, suggesting that the first OUTPUT file is being treated differently.

(Crossposted here: http://stackoverflow.com/questions/24416133/cmake-add-custom-command-issue-with-multiple-output-files [^])

Steps To Reproduce

Example CMakeLists.txt:

cmake_minimum_required(VERSION 2.8)

add_library(mybaz baz.cpp)

add_custom_command(
  OUTPUT baz2.cpp
  COMMAND cp baz.cpp baz2.cpp
  DEPENDS baz.cpp
  COMMENT "Copying baz.cpp to baz2.cpp")

add_custom_target(mytarget
  DEPENDS baz2.cpp
  COMMENT "Running mytarget")

add_dependencies(mybaz mytarget)

add_custom_command(
  OUTPUT bar.cpp baz.cpp
  COMMAND cat a.txt > bar.cpp
  COMMAND cat a.txt > baz.cpp
  DEPENDS a.txt
  COMMENT "Generating bar.cpp and baz.cpp")

======================================================

Below are the commands that I run:

> touch a.txt
> cmake .
    ...snip... (configuration runs fine)
> make
Scanning dependencies of target mytarget
[ 20%] Generating bar.cpp and baz.cpp
[ 40%] Copying baz.cpp to baz2.cpp
[ 60%] Running mytarget
[ 60%] Built target mytarget
Scanning dependencies of target mybaz
[ 80%] Building CXX object CMakeFiles/mybaz.dir/baz.cpp.o
Linking CXX static library libmybaz.a
[100%] Built target mybaz
  (everything looks good)

> touch a.txt
> make
[ 20%] Generating bar.cpp and baz.cpp
[ 40%] Running mytarget
[ 60%] Built target mytarget
Scanning dependencies of target mybaz
[ 80%] Building CXX object CMakeFiles/mybaz.dir/baz.cpp.o
Linking CXX static library libmybaz.a
[100%] Built target mybaz
  (I seem to be missing the 'Copying baz.cpp to baz2.cpp' line)

> make
[ 20%] Copying baz.cpp to baz2.cpp
[ 40%] Running mytarget
[ 60%] Built target mytarget
[100%] Built target mybaz
  ( The 'Copying baz.cpp to baz2.cpp' executes this time )

Tags

No tags attached.

Attached Files

console_output_ubuntu_14_04_cmake_2_8_12_2.txt [^] (2,558 bytes) 2014-12-04 11:41 [Show Content] [Hide Content]

vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 14.04.1 LTS
Release:	14.04
Codename:	trusty
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ cmake --version
cmake version 2.8.12.2
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ ls
CMakeLists.txt
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ cat CMakeLists.txt 
cmake_minimum_required(VERSION 2.8)

add_library(mybaz baz.cpp)

add_custom_command(
  OUTPUT baz2.cpp
  COMMAND cp baz.cpp baz2.cpp
  DEPENDS baz.cpp
  COMMENT "Copying baz.cpp to baz2.cpp")

add_custom_target(mytarget
  DEPENDS baz2.cpp
  COMMENT "Running mytarget")

add_dependencies(mybaz mytarget)

add_custom_command(
  OUTPUT bar.cpp baz.cpp
  COMMAND cat a.txt > bar.cpp
  COMMAND cat a.txt > baz.cpp
  DEPENDS a.txt
  COMMENT "Generating bar.cpp and baz.cpp")
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ touch a.txt
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ cmake .
-- The C compiler identification is GNU 4.8.2
-- The CXX compiler identification is GNU 4.8.2
-- Check for working C compiler: /usr/lib/ccache/cc
-- Check for working C compiler: /usr/lib/ccache/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/lib/ccache/c++
-- Check for working CXX compiler: /usr/lib/ccache/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/vijaypradeep/scratch/cmake_bug
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ make
Scanning dependencies of target mytarget
[ 20%] Generating bar.cpp and baz.cpp
[ 40%] Copying baz.cpp to baz2.cpp
[ 60%] Running mytarget
[ 60%] Built target mytarget
Scanning dependencies of target mybaz
[ 80%] Building CXX object CMakeFiles/mybaz.dir/baz.cpp.o
Linking CXX static library libmybaz.a
[100%] Built target mybaz
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ touch a.txt
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ make
[ 20%] Generating bar.cpp and baz.cpp
[ 40%] Running mytarget
[ 60%] Built target mytarget
Scanning dependencies of target mybaz
[ 80%] Building CXX object CMakeFiles/mybaz.dir/baz.cpp.o
Linking CXX static library libmybaz.a
[100%] Built target mybaz
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$ make
[ 20%] Copying baz.cpp to baz2.cpp
[ 40%] Running mytarget
[ 60%] Built target mytarget
[100%] Built target mybaz
vijaypradeep@vijaypradeep-vm:~/scratch/cmake_bug$

Relationships

Notes
(0036825) Shootfast (reporter) 2014-09-18 12:36	Hi, just reporting that I am also experiencing this bug on cmake 3.0.0.

(0037312) Rongcui Dong (reporter) 2014-11-28 23:17	Not reproduced on cmake version 2.8.12.2 under Ubuntu 14.04

(0037382) Vijay Pradeep (reporter) 2014-12-04 11:48	Hi Rongcui, I just repeated the posted 'steps to reproduce' on Ubuntu 14.04 with CMake 2.8.12.2, and I am still seeing the error. I've also uploaded my full console output from this test for further inspection at console_output_ubuntu_14_04_cmake_2_8_12_2.txt. I'm not sure why we would be seeing different outcomes when we're running the same OS and CMake. I think it would be insightful to compare your console output the the one I just uploaded. If you have a moment, could you please rerun the experiment and upload it? Thanks!

(0037388) Rongcui Dong (reporter) 2014-12-04 15:06	Wait, I think I misunderstood your output. Yes, it behaves exactly like your post. I missed that "Copying" part.

(0037389) Brad King (manager) 2014-12-04 15:13	I can reproduce this too. You're correct that the first output is being treated specially by the Makefile generator. I'm not sure why things were done that way. Instead the multiple output rules should list all outputs on the left hand side of the make rule. I'm working on a fix.

(0037404) Brad King (manager) 2014-12-08 09:02	Fixed and test added: Xcode: Fix rebuild with multiple custom command outputs http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=8a4c6d2d [^] Makefile: Fix rebuild with multiple custom command outputs http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=644b4688 [^] Tests: Cover rebuild with multiple custom command outputs http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=65ea5eb7 [^] Makefile: Workaround Borland Make bug with multiple outputs http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=6c67b816 [^]

(0037447) Vijay Pradeep (reporter) 2014-12-12 12:12	@(Brad King): Thanks for the fix! This will definitely help streamline users' CMake experiences when trying to put together and debug complex CMake projects.

(0038168) Brad King (manager) 2015-03-06 15:35	The fixes in 0015116:0037404 caused a major regression: Wrong behavior with 3.2.0-rc2 http://thread.gmane.org/gmane.comp.programming.tools.cmake.user/51919 [^] Using the style out1 out2: depends... commands... is actually just equivalent to out1: depends... commands... out2: depends... commands... so in parallel builds the commands run multiple times at once.

(0038169) Brad King (manager) 2015-03-06 15:39	Re 0015116:0038168: This is likely the cause of this report too: Parallel build of webkitgtk4 fails with cmake 3.2 https://bugzilla.redhat.com/show_bug.cgi?id=1199360 [^]

(0038170) Brad King (manager) 2015-03-06 15:42 edited on: 2015-03-06 20:00	Re 0015116:0038168: I've drafted the following fix: Makefile: Fix multiple custom command outputs regression http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=66a9c90c [^] which will be included in 3.2 if it passes nightly testing, and will otherwise be revised.

(0039723) Robert Maynard (manager) 2015-11-02 09:13	Closing resolved issues that have not been updated in more than 4 months.

Issue History
Date Modified	Username	Field	Change
2014-08-29 13:11	Vijay Pradeep	New Issue
2014-09-18 12:36	Shootfast	Note Added: 0036825
2014-11-28 23:17	Rongcui Dong	Note Added: 0037312
2014-12-04 11:41	Vijay Pradeep	File Added: console_output_ubuntu_14_04_cmake_2_8_12_2.txt
2014-12-04 11:48	Vijay Pradeep	Note Added: 0037382
2014-12-04 15:06	Rongcui Dong	Note Added: 0037388
2014-12-04 15:13	Brad King	Note Added: 0037389
2014-12-04 15:13	Brad King	Assigned To	=> Brad King
2014-12-04 15:13	Brad King	Status	new => assigned
2014-12-04 15:13	Brad King	Target Version	=> CMake 3.2
2014-12-08 09:02	Brad King	Note Added: 0037404
2014-12-12 11:22	Brad King	Status	assigned => resolved
2014-12-12 11:22	Brad King	Resolution	open => fixed
2014-12-12 11:22	Brad King	Fixed in Version	=> CMake 3.2
2014-12-12 12:12	Vijay Pradeep	Note Added: 0037447
2015-03-06 15:35	Brad King	Note Added: 0038168
2015-03-06 15:35	Brad King	Status	resolved => assigned
2015-03-06 15:35	Brad King	Resolution	fixed => open
2015-03-06 15:35	Brad King	Fixed in Version	CMake 3.2 =>
2015-03-06 15:39	Brad King	Note Added: 0038169
2015-03-06 15:42	Brad King	Note Added: 0038170
2015-03-06 18:14	Brad King	Note Edited: 0038170
2015-03-06 20:00	Brad King	Note Edited: 0038170
2015-03-09 09:43	Brad King	Status	assigned => resolved
2015-03-09 09:43	Brad King	Resolution	open => fixed
2015-03-09 09:43	Brad King	Fixed in Version	=> CMake 3.2
2015-03-09 09:44	Brad King	Fixed in Version	CMake 3.2 => CMake 3.2.1
2015-03-09 09:44	Brad King	Target Version	CMake 3.2 => CMake 3.2.1
2015-11-02 09:13	Robert Maynard	Note Added: 0039723
2015-11-02 09:13	Robert Maynard	Status	resolved => closed