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

[Bill Deegan]

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
>>>>>> https://pairlist4.pair.net/mailman/listinfo/scons-users
>>>>>>
>>>>> _______________________________________________
> Scons-users mailing list
> Scons-users at scons.org
> https://pairlist4.pair.net/mailman/listinfo/scons-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://pairlist4.pair.net/pipermail/scons-users/attachments/20180906/29b6127c/attachment.html>