bug#61340: 29.0.60; Extra space in xref buffer

[Dmitry Gutov <dgutov@yandex.ru>]

On 08/02/2023 20:51, Juri Linkov wrote:
>>>> This was originally an effort to give the outputted text some "breathing
>>>> room", and I think it looks a little better.
>>> Indeed, it looks better but unfortunately at the cost of caused ambiguity.
>>> I guess this is the reason why Grep and Occur don't add space.
>> I suppose we could try to tone down the colon. Occur uses 'shadow' for both
>> the number and the colon; Grep uses the color from 'default' (with an
>> underline).
>>
>> If we fontify it with 'shadow' rather than 'xref-line-number', that might
>> look a little better.
> I already forgot that the default color is too glaring since I customized
> it long ago to '(xref-line-number ((t (:inherit shadow)))).  But I also
> customized other xref faces e.g. '(xref-file-header ((t (:extend t
> :background "grey90")))), so these faces provide a better look.
> OTOH, I'm not sure if the default of xref-line-number can be changed
> because on the one hand the purple color from compilation-line-number
> is needed in grep to make them more noticeable because the line numbers
> are in the middle of the line unlike in occur.  But on the other hand
> the current theme of xref buffers matches all colors of grep, so any
> change will make their default themes different.

Here's the change I was suggesting.

The difference is subtle, but seems like an improvement:

diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index 63e065e696e..581eda0513e 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -1126,7 +1126,9 @@ xref--insert-xrefs
                                     maximize (xref-location-line
                                               (xref-item-location xref)))
             for line-format = (and max-line
-                                  (format "%%%dd:" (1+ (floor (log 
max-line 10)))))
+                                  (format
+                                   #("%%%dd:" 0 4 (face 
xref-line-number) 5 6 (face shadow))
+                                   (1+ (floor (log max-line 10)))))
             with item-text-props = (list 'mouse-face 'highlight
                                          'keymap xref--button-map
                                          'help-echo
@@ -1146,8 +1148,7 @@ xref--insert-xrefs
                          ((and (equal line prev-line)
                                (equal prev-group group))
                           "")
-                        (t (propertize (format line-format line)
-                                       'face 'xref-line-number)))))
+                        (t (format line-format line)))))
                   ;; Render multiple matches on the same line, together.
                   (when (and (equal prev-group group)
                              (or (null line)