bug#27895: 26.0.50; display-line-numbers and header-line-format alignment

[Mark Oteiza <mvoteiza@udel.edu>]

On 05/08/17 at 02:24pm, Eli Zaretskii wrote:
>> > From: Mark Oteiza <mvoteiza@udel.edu>
>> > Date: Mon, 31 Jul 2017 21:35:48 -0400
>> >
>> > Enabling display-line-numbers should affect how header-line-format is
>> > shown.
>>
>> I'm not sure I agree with this, not in this general form.  Modes use
>> header-line in different ways, and I don't think we can decide for all
>> of them up front how they should react to line numbers.
>>
>> While I agree that tabulated-list modes and ruler-mode should indeed
>> be sensitive to line numbers, because the header-line in those modes
>> should align with the rest of buffer text, a counter-example is Info
>> mode, where indenting the header-line will IMO make the display look
>> uglier, almost buggy.
>>
>> If people agree that the effect on header-line should be dependent on
>> the mode, then it follows that the fix should be in the modes, not in
>> the display engine.  Fixing tabulated-list-mode will fix all of its
>> descendants; ruler-mode will need a separate fix.  And likewise for
>> any other mode which reports a similar issue.
>
>No further comments, so I've fixed tabulated-list-mode and ruler-mode
>to be sensitive to display-line-numbers, and I'm boldly marking this
>bug done.

Thanks.  Info mode being an exception is fine I suppose, though I don't
agree that it would look buggy.

However, from -Q:

1. C-x C-b
2. M-x global-display-line-numbers-mode

The header line does not change until one does a revert-buffer in the
buffer list.  This doesn't look good to me.