--- Begin Message ---
|
Subject: |
30.0.50; nconc compiler optimization breaks user packages |
|
Date: |
Thu, 27 Apr 2023 01:50:42 +0300 |
Hello,
I'm sorry if you received similar emails from me, there were problems
with sending.
Commit e6ca5834a6eab91023e9f968b65683d0a74db1e7 ('Improved nconc and append
compiler optimisations') breaks
vertico.el package. After very long debugging time I figured out that this
commit affects behavior of
`completion-hilit-commonality` function of minibuffer.el. I don't completely
understand how it works buf try
do describe some details.
If I set breakpoint before breaking commit to 'vertico--affixate then I'll get
next stacktrace
```
Debugger entered--entering a function:
* vertico--affixate((#("report-emacs-bug" 0 1 (face
(completions-first-difference))) #("cd" 0 1 (face
(completions-first-difference))) #("5x5" 0 1 (face
(completions-first-difference))) #("arp" 0 1 (face
(completions-first-difference))) #("dbx" 0 1 (face
(completions-first-difference))) #("dig" 0 1 (face
(completions-first-difference))) #("erc" 0 1 (face
(completions-first-difference))) #("ert" 0 1 (face
(completions-first-difference))) #("eww" 0 1 (face
(completions-first-difference))) #("ftp" 0 1 (face
(completions-first-difference)))))
vertico--arrange-candidates()
vertico--exhibit()
...
```
buf if I do the same after breaking commit I'll get stacktrace
```
Debugger entered--entering a function:
* vertico--affixate((#("report-emacs-bug" 0 1 (face
(completions-first-difference))) #("cd" 0 1 (face
(completions-first-difference))) #("5x5" 0 1 (face
(completions-first-difference))) #("arp" 0 1 (face
(completions-first-difference))) #("dbx" 0 1 (face
(completions-first-difference))) #("dig" 0 1 (face
(completions-first-difference))) #("erc" 0 1 (face
(completions-first-difference))) #("ert" 0 1 (face
(completions-first-difference))) #("eww" 0 1 (face
(completions-first-difference))) #("ftp" 0 1 (face
(completions-first-difference))) . 0))
vertico--arrange-candidates()
vertico--exhibit()
...
```
As you can see, the difference is in the tail of the list. With the such tail
vertico.el package crashed with error:
```
Error in post-command-hook (vertico--exhibit): (wrong-type-argument listp 0)
```
But testing `completion-hilit-commonality` in REPL separetely from vertico.el
package
give the same result (with 0 at the end of list).
Before sending this report I have tried a lot of versions of the
vertico.el package and have the same result. So I tend to think that problem is
not directly
related to package.
--- End Message ---
--- Begin Message ---
|
Subject: |
Re: bug#63103: 30.0.50; nconc compiler optimization breaks user packages |
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Date: |
Thu, 27 Apr 2023 14:28:58 +0200 |
27 apr. 2023 kl. 12.42 skrev Daniel Mendler <mail@daniel-mendler.de>:
> I think it is
> kind of nice that `nconc' can be used as a tool to turn a proper list
> into an improper list and vice versa.
It's a bit obscure, though --
(setcdr (last X) nil)
is a lot clearer than
(nconc X nil)
and when the latter is preferred for performance, a comment might be polite to
the reader.
Anyway, a fix has been pushed to master, and the manual entry for `nconc` got
an extra example.
--- End Message ---