Selecting *Compile-log* buffer automatically

Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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Hi all,

I often tweak my elisp codes and byte-compile them.
I recently found that I had been moving focus to the *Compile-log* buffer
and burying it after byte-compiling an elisp file.
Selecting *Compile-log* buffer automatically reduces commands to do this.
After my investigation on bytecomp.el and warning.el, there seems to be no
option to select the *Compile-log* buffer automatically
when it shows up in the active frame.

Does it make sense to do
- On byte-compiling an elisp file, select the byte-compile-log-buffer
window automatically if the buffer is visible, and
- Add a variable to switch the function enable/disable.
?

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Re: Selecting *Compile-log* buffer automatically

[Eli Zaretskii]

> From: Kiso Katsuyuki <katsuyuki2388@gmail.com>
> Date: Sun, 10 Dec 2023 12:38:22 -0600
> 
> I often tweak my elisp codes and byte-compile them.
> I recently found that I had been moving focus to the *Compile-log* buffer and burying it after
> byte-compiling an elisp file.
> Selecting *Compile-log* buffer automatically reduces commands to do this.

Can you elaborate why you needed to select it?  Emacs has commands to
scroll non-selected windows, you should be able to view the
compilation log without the need to select its window.

We could, of course, provide an optional feature whereby the log
window is selected.  But in that case, I think it at least should not
be selected unconditionally, only if there are some warnings or
errors.

Thanks.

Re: Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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Hi Eli,

Thanks for the comments!

>Can you elaborate why you needed to select it?  Emacs has commands to
>scroll non-selected windows, you should be able to view the
>compilation log without the need to select its window.

In almost all my byte-compile, warnings like "Warning: assignment to free
variable...",
"Warning: the function ‘foo’ might not be defined at runtime", and etc.
occur.
Warnings and Errors have Emacs display the *Compile-log* buffer
(this is the default behavior). I usually ignores this kind of warnings,
so I just move focus to the *Compile-log* buffer window, bury it (keybind
"q" by default),
and then I can restore the original window configuration. I want to skip
the step to move focus to
the *Compile-log* buffer window.

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Re: Selecting *Compile-log* buffer automatically

[Eli Zaretskii]

> From: Kiso Katsuyuki <katsuyuki2388@gmail.com>
> Date: Sun, 10 Dec 2023 19:07:31 -0600
> Cc: emacs-devel@gnu.org
> 
> >Can you elaborate why you needed to select it?  Emacs has commands to
> >scroll non-selected windows, you should be able to view the
> >compilation log without the need to select its window.
> 
> In almost all my byte-compile, warnings like "Warning: assignment to free variable...",
> "Warning: the function ‘foo’ might not be defined at runtime", and etc. occur.
> Warnings and Errors have Emacs display the *Compile-log* buffer
> (this is the default behavior). I usually ignores this kind of warnings,
> so I just move focus to the *Compile-log* buffer window, bury it (keybind "q" by default),
> and then I can restore the original window configuration. I want to skip the step to move focus to
> the *Compile-log* buffer window.

So maybe we should indeed add an optional behavior, for those case.

Do you agree that the compile log window should be only selected if
there are actually warnings or errors during the last compilation?

Re: Selecting *Compile-log* buffer automatically

[Juri Linkov]

> I recently found that I had been moving focus to the *Compile-log* buffer
> and burying it after byte-compiling an elisp file.
> Selecting *Compile-log* buffer automatically reduces commands to do this.
> After my investigation on bytecomp.el and warning.el, there seems to be no
> option to select the *Compile-log* buffer automatically
> when it shows up in the active frame.
>
> Does it make sense to do
> - On byte-compiling an elisp file, select the byte-compile-log-buffer
> window automatically if the buffer is visible, and
> - Add a variable to switch the function enable/disable.
> ?

I believe this should be customizable with something like

  (setopt display-buffer-alist
   '(("\\*Compile-log\\*" nil (select-window . t))))

Re: Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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>Do you agree that the compile log window should be only selected if
>there are actually warnings or errors during the last compilation?

Yes. I'll be careful about the case when the *Compile-Log* buffer
window is visible before byte-compile-file is invoked.

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Re: Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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>I believe this should be customizable with something like
>
>  (setopt display-buffer-alist
>   '(("\\*Compile-log\\*" nil (select-window . t))))

Hi Juri,

Thank you for the advice, but I tried this and it didn't work.
*Compile-log* buffer isn't selected.
I used emacs 29.1 with no init files loaded.
I'll consider a different way.

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Re: Selecting *Compile-log* buffer automatically

[Juri Linkov]

>>I believe this should be customizable with something like
>> 
>>  (setopt display-buffer-alist
>>   '(("\\*Compile-log\\*" nil (select-window . t))))
>
> Thank you for the advice, but I tried this and it didn't work.
> *Compile-log* buffer isn't selected.
> I used emacs 29.1 with no init files loaded.

This feature was discussed in bug#33258 and bug#46034,
but not yet implemented.  It should be easy to implement
exactly the same way as 'windmove-display-in-direction'
selects the old or new window in 'post-command-hook'.
Ok, I will post a patch to bug-gnu-emacs.

> I'll consider a different way.

Until this is pushed, you could use such a simple advice
that does the same:

(define-advice dired-do-byte-compile (:after (&rest _args) select-window)
  (when-let ((window (get-buffer-window "*Compile-Log*" 0)))
    (select-window window)))

Re: Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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>>>I believe this should be customizable with something like
>>>
>>>  (setopt display-buffer-alist
>>>   '(("\\*Compile-log\\*" nil (select-window . t))))
>>
>> Thank you for the advice, but I tried this and it didn't work.
>> *Compile-log* buffer isn't selected.
>> I used emacs 29.1 with no init files loaded.
>
>This feature was discussed in bug#33258 and bug#46034,
>but not yet implemented.  It should be easy to implement
>exactly the same way as 'windmove-display-in-direction'
>selects the old or new window in 'post-command-hook'.
>Ok, I will post a patch to bug-gnu-emacs.

There seems to be another problem with using display-buffer-alist.
byte-compile-file repeats byte-compile, display-warning (this uses
display-buffer)
for each S-expression. Selecting *Compile-log* buffer before finishing
byte-compiling the last
S-expression causes an error. I checked the error using

(defun select-visible-warning-buffer (_type _message &optional _level
buffer-name)
  "Select the visible warning buffer"
  (unless buffer-name
    (setq buffer-name "*Warnings*"))
  (let ((window (get-buffer-window (get-buffer buffer-name))))
    (if window (select-window window))))

(advice-add 'display-warning :after #'select-visible-warning-buffer)

, and byte-compile causes "Error: End of file during parsing".

display-buffer-alist should affect every display-buffer, so I think
it leads to the same error.

I think selecting the *Compile-Log* buffer separately from display-buffer
is easier. I made the attached patch to select *Compile-Log* buffer
for emacs 29.1 bytecomp.el.


>> I'll consider a different way.
>
>Until this is pushed, you could use such a simple advice
>that does the same:
>
>(define-advice dired-do-byte-compile (:after (&rest _args) select-window)
>  (when-let ((window (get-buffer-window "*Compile-Log*" 0)))
>    (select-window window)))

Thanks. I referred to this when I made the above patch.

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diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 5df1205869c..b9b5b93d1a2 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -1311,10 +1311,13 @@ where the problem was detected.  FILL is a prefix as in
 `warning-fill-prefix'.  LEVEL is the level of the
 problem (`:warning' or `:error').  FILL and LEVEL may be nil.")
 
+(defvar byte-compile-warning-flag nil)
+
 (defun byte-compile-log-warning (string &optional fill level)
   "Log a byte-compilation warning.
 STRING, FILL and LEVEL are as described in
 `byte-compile-log-warning-function', which see."
+  (setq byte-compile-warning-flag t)
   (funcall byte-compile-log-warning-function
            string
            (or (byte-compile--warning-source-offset)
@@ -2118,6 +2121,9 @@ See also `emacs-lisp-byte-compile-and-load'."
 		 (y-or-n-p (format "Save buffer %s first? " (buffer-name b))))
 	    (with-current-buffer b (save-buffer)))))
 
+  ;; Reset the warning flag
+  (setq byte-compile-warning-flag nil)
+
   ;; Force logging of the file name for each file compiled.
   (setq byte-compile-last-logged-file nil)
   (let ((byte-compile-current-file filename)
@@ -2244,6 +2250,11 @@ See also `emacs-lisp-byte-compile-and-load'."
 			      target-file))))))
           (unless byte-native-compiling
 	    (kill-buffer (current-buffer))))
+
+	;; select the byte compile log
+	(if byte-compile-select-log-buffer
+	    (if byte-compile-warning-flag (select-visible-byte-compile-log)))
+
 	(if (and byte-compile-generate-call-tree
 		 (or (eq t byte-compile-generate-call-tree)
 		     (y-or-n-p (format "Report call tree for %s? "
@@ -2263,6 +2274,17 @@ See also `emacs-lisp-byte-compile-and-load'."
             (load target-file))
 	t))))
 
+(defcustom byte-compile-select-log-buffer nil
+  "If non-nil, the `byte-compile-log-buffer' window in the selected frame
+is selected when there are warnings."
+  :type 'boolean
+  :group 'bytecomp)
+
+(defun select-visible-byte-compile-log ()
+  "Select the visible byte compile log buffer in the selected frame"
+  (when-let ((window (get-buffer-window byte-compile-log-buffer)))
+    (select-window window)))
+
 ;;; compiling a single function
 ;;;###autoload
 (defun compile-defun (&optional arg)

Re: Selecting *Compile-log* buffer automatically

[Juri Linkov]

>>>>I believe this should be customizable with something like
>>>> 
>>>>  (setopt display-buffer-alist
>>>>   '(("\\*Compile-log\\*" nil (select-window . t))))
>>>
>>> Thank you for the advice, but I tried this and it didn't work.
>>> *Compile-log* buffer isn't selected.
>>> I used emacs 29.1 with no init files loaded.
>> 
>>This feature was discussed in bug#33258 and bug#46034,
>>but not yet implemented.  It should be easy to implement
>>exactly the same way as 'windmove-display-in-direction'
>>selects the old or new window in 'post-command-hook'.
>>Ok, I will post a patch to bug-gnu-emacs.
>
> There seems to be another problem with using display-buffer-alist.
> byte-compile-file repeats byte-compile, display-warning (this uses
> display-buffer)
> for each S-expression. Selecting *Compile-log* buffer before finishing
> byte-compiling the last
> S-expression causes an error. I checked the error using 
>
> (defun select-visible-warning-buffer (_type _message &optional _level
> buffer-name)
>   "Select the visible warning buffer"
>   (unless buffer-name
>     (setq buffer-name "*Warnings*"))
>   (let ((window (get-buffer-window (get-buffer buffer-name))))
>     (if window (select-window window))))
>
> (advice-add 'display-warning :after #'select-visible-warning-buffer)
>
> , and byte-compile causes "Error: End of file during parsing".
>
> display-buffer-alist should affect every display-buffer, so I think
> it leads to the same error.

Indeed, you can't select arbitrary windows in every display-buffer,
because code after every display-buffer expects certain buffers
to be selected.  This was discussed in bug#33258, and the only
possible solution is to select the window when the current command
finishes.  This is implemented in bug#67993.

Re: Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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>Indeed, you can't select arbitrary windows in every display-buffer,
>because code after every display-buffer expects certain buffers
>to be selected.  This was discussed in bug#33258, and the only
>possible solution is to select the window when the current command
>finishes.  This is implemented in bug#67993.

I checked #67993, used the patch, and the *Compile-Log* buffer was selected
successfully without the error. If #67993 is implemented, I'll use
display-buffer-alist.
Otherwise I'll modify bytecomp.el without using display-buffer-alist.
I figured out that the post-command-hook is useful.

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Re: Selecting *Compile-log* buffer automatically

[Kiso Katsuyuki]

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I found the bug #67993 fixed. This is closed. Thank you!

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