[Scons-users] Dependencies and Pseudo Builders

Tue Sep 8 08:55:30 EDT 2020

Hi!
Thank You! You're great!
I've started my journey across the Scons again, from scratch.
I've read the article (https://github.com/SCons/scons/wiki/ToolsForFools)
that you have mentioned and I've replaced my PseudoBuilders by Builder
packed into Tool. I think my SCons understanding is far better than
yesterday, but I still have a bunch of questions...

Also thank you for your patience and teaching me "how to fish" :-)

Point 3)
>> There a problem appears, I've written following pseudo builder:
>>
>>     def run_test(env, path):
>>         try:
>>             process_output = subprocess.run([path], check=True,
>> stdout=subprocess.PIPE, universal_newlines=True).stdout
>>         except subprocess.CalledProcessError as e:
>>             process_output = e.output
>>
>>         return process_output
>>
>> As you can see there is no created any files, all results of the call is
>> stored in memory. So I just need to return that results.
>> But if I add it to env:
>> test_result = env.RunTest(path)
>> env.Depend(test_result, program)
>> then that builder is called too early (before source code is built) and I
>> have no idea how to make a correct dependency between Program from Point2
>> and it's run in Point3. I suppose that builder should return something from
>> SCons env but I have no idea what it should be.
>>
>
> What do you want to do with the results?
> Be explicit.
>

I would like to start unit tests, grab the outputs (which is useless
without processing), analyze them, and convert them to XML and HTML
formats.

Correct me if I'm wrong:
 1. I should use Builder instead of PseudoBuilder
 2. So my Builder should take a list of Program compiled before as a
$SOURCE
 3. My Builder may call a Python function instead of calling any app
(following https://scons.org/doc/production/HTML/scons-user/ch18s04.html),
that function does all that Pythonic things

Again
Enormous Thank You!

pon., 7 wrz 2020 o 17:05 Bill Deegan <bill at baddogconsulting.com> napisał(a):

> Greetings,
>
> You've got a lot of things not correct.. ;)
> But as a newbie.. to be expected.
>

So true :-)

> What documents have you read?
> Did you read the users guide?
> (That's a good place to start)
> *Don't just start googling stuff and follow random stackoverflow pages..
> you'll end up with a giant mess that probably doesn't work, probably isn't
> correct even if it does work and zero understanding of how to do it
> correctly.*
>
>
So true, again.

See comments inline below.
>
>
> On Sun, Sep 6, 2020 at 7:31 PM Michał Palczewski <
> michal.palczewski at gmail.com> wrote:
>
>> Hi Everybody!
>> At the very beginning, I would like to say Hello! to everybody, I'm a
>> newbie here :-D
>>
>> But let's go to the point. Frankly speaking I need some help to write
>> correct and SConsy idiomatic SConstruct to generate, build, and run unit
>> tests. The entire flow is as follows:
>>
>> 1) Generate Unity 'test_runner' code - I use provided Unity test runner
>> generator, it's Ruby script
>> 2) Build Program, where the code generated in point 1 is one of the input
>> source files
>> 3) Run the Program that has been build in point 2
>> 4) Get the results and start Python script to analyze the results.
>>
>> Generally, I think I know (or not....) how to perform each action, but I
>> cannot ling all of them together to force the correct order of those steps.
>>
>> Let's describe my ideas:
>>
>> Point 1)
>> To do Point1 I've made a PseudoBuilder (basing on:
>> https://scons.org/doc/production/HTML/scons-user/ch20.html)
>>
>>     def generate_runner(env, test, test_runner):
>>         os.makedirs(os.path.dirname(test_runner), exist_ok=True)
>>         env.Execute(f"ruby
>> {env['UNITY_DIR']}/auto/generate_test_runner.rb {test} {test_runner}")
>>         return SCons.Node.FS.FS().File(test_runner)
>> ...
>> env.AddMethod(generate_runner, "GenerateRunner")
>>
>> Is it Execute correct here?
>>
>
> All the above is completely incorrect.
>

Yeah.

> You want to create a builder here and not a psuedo builder.
> You should (Almost) never use Execute.
> You should (Almost) never have to explicitly create a File node.. Not sure
> how you went down that path.
> If there's some scons docs that lead you that way please let us know so we
> can revise them.
>
> See the user guide,  the man page, and also this wiki page
> https://github.com/SCons/scons/wiki/ToolsForFools
>
> Do you have to create many test running source files? (or just one, if
> just one, then env.Command() will likely do the trick)
>
>
>
>> Point 2)
>> To do Point2 I've used build-in Builder combined by dependency with my
>> own one:
>>
>> runner = env.GenerateRunner('test_case_source", "test_case_runner.c")
>> program = env.Program(name="test_case_name",
>> souces=['test_case_source.c', 'test_case_runner.c']
>>
>> env.Depends(program, runner)
>>
>> And until this Point everything seems to be working correctly.
>> In fact, all files from Point 1 are generated in single run but it always
>> happens before Point 2,
>>
>> .e.g.:
>> ruby
>> ruby
>> ruby
>> gcc
>> gcc
>> gcc
>>
>> when I would expect (doubtfully?):
>> ruby
>> gcc
>> ruby
>> gcc
>> ruby
>> gcc
>>
>> but I stop thinking about that because it generally works
>>
>
> Another important point. DONT try to force order. The correct way to use
> SCons (and really any build system), is to list dependencies. The tools
> should connect the dots for you.
>
> And if you have to use Depends() you're probably doing something wrong.
>
> If you have a builder (which you should) which generates
> test_case_runner.c from test_case_source, and you have
> a Program() which has test_case_runner.c as a source. No need to do
> anything else. SCons will figure that out.
>
>
>> Point 3)
>> There a problem appears, I've written following pseudo builder:
>>
>>     def run_test(env, path):
>>         try:
>>             process_output = subprocess.run([path], check=True,
>> stdout=subprocess.PIPE, universal_newlines=True).stdout
>>         except subprocess.CalledProcessError as e:
>>             process_output = e.output
>>
>>         return process_output
>>
>> As you can see there is no created any files, all results of the call is
>> stored in memory. So I just need to return that results.
>> But if I add it to env:
>> test_result = env.RunTest(path)
>> env.Depend(test_result, program)
>> then that builder is called too early (before source code is built) and I
>> have no idea how to make a correct dependency between Program from Point2
>> and it's run in Point3. I suppose that builder should return something from
>> SCons env but I have no idea what it should be.
>>
>
> What do you want to do with the results?
> Be explicit.
>
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