On Wed, 2020-01-22 at 16:39 +0000, Rasmus Villemoes wrote:
> On 22/01/2020 16.50, Richard Purdie wrote:
> > On Wed, 2020-01-22 at 15:46 +0000, Rasmus Villemoes wrote:
> > > On 22/01/2020 15.35, Richard Purdie wrote:
> > > > Bitbake can only detect direct references to variables. The
> > > > code
> > > > above only runs at configure time, not at parse time so its not
> > > > really surprising that bitbake can't know what its doing.
> > >
> > > Well, I thought that as well at first. But there must be
> > > something
> > > done at run-time to feed back the variable dependencies, because
> > > if I
> > > add a completely dumb
> > >
> > > python do_configure() {
> > > import fileinput
> > > + d.getVar("VARIABLE") # silly
> > > with open("foo.txt", "w") as out:
> > > for line in
> > > fileinput.input(files=d.getVar("FOO_INPUT").split()):
> > > line = d.expand(line)
> > > out.write(line)
> > > }
> > >
> > > build the recipe (because now it has of course changed), and then
> > > change VARIABLE, the recipe does get re-built. Or does bitbake
> > > specifically look for d.getVar(<literal>) when it parses a python
> > > function?
> >
> > Bitbake has ASTs for all its python fragments and can search those
> > for
> > getVar() calls. It will spot getVar("X") but can't know what is in
> > d.expand(line).
>
> Yeah, I just tried changing it to
>
> v1 = "VAR"
> v2 = "IABLE"
> d.getVar(v1 + v2)
>
> and bitbake no longer knew about the dependency on VARIABLE :(
>
> I can't be the first one to want to substitute bitbake variables in
> various source files, without necessarily knowing upfront which
> variables might appear.
>
> So thinking out loud (and apologies if this is very silly): Would it
> be
> possible to implement some auto-deps class that a recipe playing the
> above game could inherit. Something like
>
> AUTO_DEPS_TASKS = "configure"
> python() {
> for t in AUTO_DEPS_TASKS:
> f = (tmpdir/cachedir/somewhere)/autodeps/pn/t.inc
> if f does not exist:
> make sure the recipe gets rebuilt
> return
> include f
> }
>
> python write_autodeps(d, t):
> logic to write a "do_t[vardeps] += ..." line to f, called at the
> end
> of t (preferably automatically, but manually if need be)
>
> python expand_autodeps(d, s):
> helper to be used within an autodeps task, recording any variable
> used
> in the expansion of s
Why not do what I already suggested?
I suspect rather than a class you're looking for a helper function in
lib/oe to call into? Just move my suggested function somewhere there?
Cheers,
Richard
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