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

[RW]

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
>>>>> https://pairlist4.pair.net/mailman/listinfo/scons-users
>>>>>
>>>>
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