[Scons-users] File / Dir relative paths and SConscriptChdir

[RW]

Hi Bill,
I've replaced File with os.path.normpath / os.path.abspath
(to make sure the slashes are the right way round for Windows or Linux)
and I'm now running it directly in the SConscript instead of as a builder
since there are no sources for this particular one
(but there will be for others)

```
header = env.subst('${HEADER_BUILD}/mpversion.h')
header = os.path.normpath(header)
script = env.subst('${TOP}/py/makeversionhdr.py')
script = os.path.abspath(script)
env.Execute(script + ' ' + header, chdir=env.GetLaunchDir())
```

I was using File() instead of env.File which is why the variable
substitution failed from the looks of things


On Fri, 7 Sep 2018 at 02:11, Bill Deegan <bill at baddogconsulting.com> wrote:

> So much that could be improved with your code example below.
> Firstly almost no reason to use File() or Dir(), just use a string.
> Secondly no need to have File(subst...) use File("${TOP}/....")
>
> And never have a builder with no sources. If it's no sources that means it
> can be run when the SConstruct/SConscript is processed, so use  Execute.
> If it can't be run when SConstruct/SConscripts are processed, then it
> depends on something, and you should list those as sources.  Your builder
> can pick and choose what of $SOURCES it uses (or nothing).
>
> What directory does your SConstruct live in?
>
> -Bill
>
> On Thu, Sep 6, 2018 at 7:56 PM RW via Scons-users <scons-users at scons.org>
> wrote:
>
>> I've sorted it out now so no worries, I've also removed the
>> SConscriptChdir() call
>>
>> what I've basically got is
>> a SConscript within a directory such as
>> D:\Temp\micropython\ports\minimal
>> (there being multiple ports under different directories
>>
>> This then pulls in a seperate common SConscript under a path such as
>> D:\Temp\micropython\tools\scons\micropy.py
>>
>> via SConscript('../../tools/scons/micropy.py', {'env': env})
>>
>> because the common script lives in a different directory I needed to make
>> sure the paths resolved correctly
>> Putting in a # at the beginning of the path seems to work best
>> this way it will resolve to D:\Temp\micropython\ports\minimal instead of
>> D:\Temp\micropython\tools\scons
>> which is where the top level script lives
>>
>> As a simple extract
>> ```
>> # TOP Resolves to D:\Temp\micropython
>> env.SetDefault(TOP=Dir('../..'))
>>
>> env.SetDefault(BUILD='build')
>> env.Replace(HEADER_BUILD='${BUILD}/genhdr')
>>
>> # Build the micropython version header
>> def build_mpversion(target, source, env):
>>     # Use File to make sure the directory seperator is the correct way
>> round
>>     cmd = File(env.subst('${TOP}/py/makeversionhdr.py')).abspath
>>     cmd += ' ' + target[0].path
>>     env.Execute(cmd, chdir=env.GetLaunchDir())
>>
>> tgt = env.Command('#${HEADER_BUILD}/mpversion.h', [], build_mpversion)
>> ```
>>
>> Note there's a lot more in this file than just this
>> and part of the initial exercise is to just try and keep the existing
>> logic / if statements
>> from the old Makefile intact to make sure it works before I start to
>> re-arrange stuff to clean it up
>>
>> One thing I have noticed is that if you provide a construction variable
>> as part of the name to a File or Dir
>> such as File('${TOP}/py/makeversionhdr.py') then run .abspath on it for
>> the full path
>> it doesn't look like it expands out the construction variable
>>
>> but this does work
>> env.Replace(TEST1=Dir('../..'))
>> env.Replace(TEST2='$TEST1\\additionaldir')
>> test1 = env.subst('$TEST2')
>> # test1 now equals D:\Temp\micropython\additionaldir
>>
>> On Thu, 6 Sep 2018 at 23:39, Bill Deegan <bill at baddogconsulting.com>
>> wrote:
>>
>>> What command line are you seeing?
>>> Get rid of your SConscriptChdir() call.
>>> I never use it.
>>> You can add as an argument to SConscript, but generally the default
>>> behavior just works.
>>>
>>> Chdir generally breaks parallel builds.
>>> It's possible the default mentioned in the manpage is incorrect. As far
>>> as I know all paths are specified from dir and chdir is only done if
>>> explicitly specified to a builder..
>>>
>>> On Thu, Sep 6, 2018 at 5:58 PM Bill Deegan <bill at baddogconsulting.com>
>>> wrote:
>>>
>>>> So you have two builders with empty sources?
>>>> Not good practice.
>>>>
>>>> Use Execute if you want it to always run..
>>>> -Bill
>>>>
>>>> On Thu, Sep 6, 2018 at 5:18 PM RW <garlicbready at googlemail.com> wrote:
>>>>
>>>>> Hi Bill,
>>>>> I think I've figured it out
>>>>> basically I'm trying to use relative paths which are relative to the
>>>>> top level SConstruct file
>>>>> instead of being relative to a second called script in another
>>>>> directory
>>>>>
>>>>> the first way around this is to use the directory parameter
>>>>> tgt = env.Command(File('testfile.txt', directory ='../src1'), [],
>>>>> build_test)
>>>>>
>>>>> the second way around this is to prefix the path with #
>>>>> tgt = env.Command(File('#testfile.txt'), [], build_test)
>>>>>
>>>>>
>>>>> On Thu, 6 Sep 2018 at 22:10, Bill Deegan <bill at baddogconsulting.com>
>>>>> wrote:
>>>>>
>>>>>> Perhaps you can explain what you're actually trying to do, rather
>>>>>> than providing a toy example?
>>>>>> That will help provide more context correct help.
>>>>>>
>>>>>> On Thu, Sep 6, 2018 at 4:23 PM RW via Scons-users <
>>>>>> scons-users at scons.org> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>> I've got another question, this is over the use of SConscriptChdir
>>>>>>> such as env.SConscriptChdir(0)
>>>>>>> from what I can gather when specifying a File or Dir object or
>>>>>>> making a call to a Command builder at least which will automatically
>>>>>>> convert a string target to a File object.
>>>>>>>
>>>>>>> The File / Dir object will always be relative to the current
>>>>>>> SConstruct file.
>>>>>>> Not relative to the originating SConstruct file (which is what I'm
>>>>>>> trying to do)
>>>>>>>
>>>>>>> To give an example
>>>>>>>
>>>>>>> src1\test1.txt - empty test file
>>>>>>> src1\test2.txt - empty test file
>>>>>>>
>>>>>>> src1\SConstruct
>>>>>>> ```
>>>>>>> import os
>>>>>>>
>>>>>>> EnsureSConsVersion(3, 0, 0)
>>>>>>>
>>>>>>> # Setup the construction env
>>>>>>> env = Environment(ENV={'PATH': os.environ['PATH']})
>>>>>>>
>>>>>>> # Set working directory to not change
>>>>>>> env.SConscriptChdir(0)
>>>>>>>
>>>>>>> # Load in an external script
>>>>>>> SConscript('../src2/testsubscript.py', {'env': env})
>>>>>>> ```
>>>>>>>
>>>>>>> src2\SConstruct
>>>>>>> ```
>>>>>>> # Import the scons environment from the calling script
>>>>>>> Import('env')
>>>>>>>
>>>>>>> def build_test(target, source, env):
>>>>>>>     # At this point the 'testfile.txt' will be automatically changed
>>>>>>> to a File class by SCons
>>>>>>>
>>>>>>>     # print the path scons thinks this file is located at
>>>>>>>     print(target[0].path)
>>>>>>>
>>>>>>> tgt = env.Command(File('testfile.txt'), [], build_test)
>>>>>>> env.Default(tgt)
>>>>>>>
>>>>>>> tgt2 = env.Command('testfile2.txt', [], build_test)
>>>>>>> env.Default(tgt2)
>>>>>>>
>>>>>>> # Even though SConscriptChdir is set to 0 in the originating env,
>>>>>>> File uses the current script as it's reference point
>>>>>>> # D:\Temp\testproject\src2\testfile.txt
>>>>>>> # D:\Temp\testproject\src2\testfile2.txt
>>>>>>> ```
>>>>>>>
>>>>>>> Is this expected behaviour?
>>>>>>> perhaps SConscriptChdir only influences when calling exe's rather
>>>>>>> than the use of File or Dir
>>>>>>> is there some public API way of setting the current directory for
>>>>>>> File / Dir calls?
>>>>>>> thats not the directory of the current SConsscript
>>>>>>> since builders wrap everything in a File automatically, it might
>>>>>>> mean I have to make sure all file paths are absolute before hand.
>>>>>>>
>>>>>>> Many Thanks
>>>>>>> Richard
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Scons-users mailing list
>>>>>>> Scons-users at scons.org
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>>>>>>>
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>
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