bug#63959: python-mode does not keep indentation in square brackets []

[kobarity]

Andreas Röhler wrote:
> >> However, it may happen that the previous line is indented for the
> >> inner paren as in the ERT `python-indent-inside-paren-2':
> >> 
> >> data = {'key': {
> >>      'objlist': [
> >>          {'pk': 1,
> >>           'name': 'first'},
> >>          {'pk': 2,
> >>           'name': 'second'}
> >>      ]
> >> }}
> >> 
> >> The line "{'pk': 2," is considered as the continuation line, but it
> >> should not respect the indentation of the PREVIOUS line "'name':
> >> 'first'},".  So skipping such lines with inner parens were needed.
> >> It searches backward for the line which starts with the item of the
> >> same opening paren as the target line.
> >> 
> >> In the case of the above example, if the target line is "{'pk': 2,",
> >> its opening paren is "[" in the line "'objlist': [".  It first checks
> >> the previous line "'name': 'first'},", but its opening paren is "{" in
> >> "{'pk': 1,".  So this line is skipped.  Next, it checks the line
> >> "{'pk': 1," and its opening paren is "[" in the line "'objlist': [",
> >> which is same as the target line.  So the target line's indentation
> >> will be as same as the line "{'pk': 1,".
> >> 
> >> It would be helpful if you could try this patch.
> > Thank you, tested, works for me!
> > 
> >> Does anyone think we should have a customize variable that switches
> >> between the traditional behavior of ignoring the indentation of the
> >> previous line and this new behavior?
> > I doubt it's useful. It is in general how indentation works in many modes, 
> > and I
> > don't think there ever been a variable to disable that. Stefan Monnier in
> > particular has a paper called "SMIE: weakness is power", where such 
> > indentation
> > is shortly discussed.
> > 
> > 
> > IMO the question of previous lines indentation isn't raised here, as a more 
> > specific rule applies: inside a non-empty list
> > indent with its first element. Whereas if list starts empty, as with "[" 
> > here, next indents as that line plus offset.

Let me explain it again.  I added the line numbers.

1: data = {'key': {
2:     'objlist': [
3:         {'pk': 1,
4:          'name': 'first'},
5:         {'pk': 2,
6:          'name': 'second'}
7:     ]
8: }}

I think you are saying that the third line will be indented with an
additional offset to the second line, am I correct?  If so, I totally
agree with you.  This behavior has not changed with my patch.

What I wanted to say in the previous mail is that the fifth line
should align with the third line, not the fourth line.

As for such standard indentation, my patch does not change the
behavior.

However, if the user intentionally changed the indentation of the
third line, the current Python mode would indent the fourth and
subsequent lines as follows:

1: data = {'key': {
2:     'objlist': [
3:             {'pk': 1,  # Intentionally changed
4:              'name': 'first'},
5:         {'pk': 2,
6:          'name': 'second'}
7:     ]
8: }}

After applying my patch, it is indented as follows:

1: data = {'key': {
2:     'objlist': [
3:             {'pk': 1,  # Intentionally changed
4:              'name': 'first'},
5:             {'pk': 2,
6:              'name': 'second'}
7:     ]
8: }}