[OE-core] Submission of 'emit-buildvars' class?

[Enrico Scholz]

Alexander Kanavin <alex.kanavin at gmail.com> writes:

>> I do not know, how this can be done with plain OE.  As said, SDKs are too
>> heavy weighted, 'devshell' too slow and can not be scripted, 'externalsrc'
>> is broken, slow and can not be scripted.
>
> For better or worse, Yocto Project has standardized on devtool (not
> devshell!)

'devtool' is for writing recipes, not for writing software.


> and externalsrc for these kind of local development workflows. You are
> very welcome to improve and add to them, so they are not broken

I tried 'externalsrc' after the per-package sysroot changes but just run
into bugs (class tried to write into read-only mounted source dir, every
2nd 'do_fetch' failed because sysroot was already populated).


Doing a 'make -f ../Makefile.common install' which writes data directly
into the NFS root is much faster than doing all the steps of the dev*
tools.


> or slow,

They *are* slow.

| $ cd workspace/kernel
| 
| $ git commit -m 'empty' --allow-empty
| 
| $ time bitbake linux-mainline
| real    4m7.417s
| user    0m0.763s
| sys     0m0.110s

vs.

| time make -f ../Makefile.kernel  -j12
| real    0m13.204s
| user    0m54.888s
| sys     0m17.970s



Even a plain 'bitbake'  is takes 0.5 sec:

| $ time bitbake
| Nothing to do.  Use 'bitbake world' to build everything, or run 'bitbake --help' for usage information.
| 
| real    0m0.588s
| user    0m0.255s
| sys     0m0.023s

vs.

| $ time make
| real    0m0.007s
| user    0m0.002s
| sys     0m0.005s



And some things are impossible because they are not supported by the
design.  E.g. how would would you implement the flymake 'check-syntax'
target[1]

| check-syntax:
|         gcc -o /dev/null -S ${CHK_SOURCES} || true

with devtool/devshell/externalsrc?


Deciding which task to execute (compile, do_compile_kernelmodules) and
installation into NFS root is not supported by dev* either.



Enrico


Footnotes: 
[1]  https://www.gnu.org/software/emacs/manual/html_mono/flymake.html#Example_002d_002d_002dConfiguring-a-tool-called-via-make

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