URL:
<https://savannah.gnu.org/bugs/?59762>
Summary: make --touch produce local spurious empty files with
out-of-tree Makefile strategy
Project: make
Submitted by: None
Submitted on: Thu 24 Dec 2020 03:43:44 PM UTC
Severity: 3 - Normal
Item Group: Bug
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Component Version: 4.1
Operating System: POSIX-Based
Fixed Release: None
Triage Status: None
_______________________________________________________
Details:
We implemented the out-of-tree compilation strategy
(http://make.mad-scientist.net/papers/multi-architecture-builds/#target.mk)
described by Paul D. Smith on his blog (http://mad-scientist.net/).
We are very thankful for this method as it helped simplify a lot our
multi-architecture compilation process.
However, when using `make --touch` it also `touch` files in the root
directory, files named after all targets that needed to be touched (it also
touch the proper targets in their own build directories).
I observed this issue with `make` 4.1 on Ubuntu 18.04.2 LST and 4.2.1 on
Debian 10 and SUSE Linux Enterprise Server 15.
I made a simplified reproduction usecase which is available on gitlab and can
be obtained with
git clone https://gitlab.com/martn/makeTouchIssue.git
I also attach the simplified `Makefile` and `target.mk` for easier reference
(the actual sources are just dummy files).
Here is the scenario:
make
pgm.o: file1.o file2.o
file2.o: file1.o
The compilation follows the out-of-tree strategy above mentioned; it compiles
in `./build`.
0 I make a full build of a project
$ ls src/
file1.f90 file2.f90 pgm.f90
$ make
compiling file1.o
compiling file2.o
compiling pgm.o
linking pgm.x
:
$ ls build/
file1.o file2.o pgm.o pgm.x
0 I touch `src/file1.f90` (simulating a modification to the code that would
not change any interface)
0 `make` would then want to rebuild everything
But in fact I would just need to recompile `file1.o` and relink `pgm.x`.
0 So I recompile `file1.o` and use `make --touch` to prevent recompiling the
other objects
$ make file1.o
compiling file1.o
:
$ make --touch file2.o pgm.o
touch file2.o
touch pgm.o
touch file2.o
touch pgm.o
Here is the issue; it did touch the object files in `./build` but also touched
two (empty) files in `./`:
$ ls
build file2.o Makefile pgm.o README.md src target.mk
Although I am not sure, I think it is related to the `target.mk` mechanics; so
it might not be a bug, but simply an unwanted side effect.
After concerting with my colleagues we thought pertinent to mention it.
Obviously for real project, these spurious files can seriously clutter the
root directory.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Thu 24 Dec 2020 03:43:44 PM UTC Name: Makefile Size: 835B By: None
<http://savannah.gnu.org/bugs/download.php?file_id=50561>
-------------------------------------------------------
Date: Thu 24 Dec 2020 03:43:44 PM UTC Name: target.mk Size: 322B By: None
<http://savannah.gnu.org/bugs/download.php?file_id=50562>
_______________________________________________________
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