bug#74772: [PATCH] Consistently add wildcards for completion-pcm-leading-wildcard

[Spencer Baugh via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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Tags: patch


completion-pcm--find-all-completions has two different phases:
First we turn the minibuffer text into a regex and matches
completion alternatives against it.  If that finds no matches,
then we strip some text off the completions and minibuffer text
and call ourselves recursively to find completions, then filter
the results with the removed text (converted into a regex).

Because of this, completion-pcm-leading-wildcard had
inconsistent behavior: in the second phase, the filter created
from the removed text would have a leading wildcard.  That
effectively adds wildcards in the middle of the minibuffer text
at the start of each "word".  But the first phrase created a
regex which had no such wildcards.  Thus, the two phases could
get substantially different results.

We fix this by changing completion-pcm-leading-wildcard to
consistently add a leading wildcard for each word.  This was
always my intention.

* lisp/minibuffer.el (completion-pcm--string->pattern): Include
a wildcard after each delimter with
completion-pcm-leading-wildcard.
* lisp/minibuffer.el (completion-pcm-leading-wildcard): Update
docs.
* doc/emacs/mini.texi (Completion Styles): Update docs.

In GNU Emacs 29.2.50 (build 11, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.15.12, Xaw scroll bars) of 2024-12-02 built on
 igm-qws-u22796a
Repository revision: ddde0f4eead134864c7db775c0aeb93f201c35f6
Repository branch: my-emacs-29
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Rocky Linux 8.10 (Green Obsidian)

Configured using:
 'configure --with-x-toolkit=lucid --without-gpm --without-gconf
 --without-selinux --without-imagemagick --with-modules --with-gif=no
 --with-tree-sitter --with-native-compilation=aot
 PKG_CONFIG_PATH=/usr/local/home/garnish/libtree-sitter/0.22.6-1/lib/pkgconfig/'


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From c6229d0dc2d78486dac00e5a8a1d6f95a08b80fd Mon Sep 17 00:00:00 2001
From: Spencer Baugh <sbaugh@janestreet.com>
Date: Tue, 10 Dec 2024 12:41:49 -0500
Subject: [PATCH] Consistently add wildcards for
 completion-pcm-leading-wildcard

completion-pcm--find-all-completions has two different phases:
First we turn the minibuffer text into a regex and matches
completion alternatives against it.  If that finds no matches,
then we strip some text off the completions and minibuffer text
and call ourselves recursively to find completions, then filter
the results with the removed text (converted into a regex).

Because of this, completion-pcm-leading-wildcard had
inconsistent behavior: in the second phase, the filter created
from the removed text would have a leading wildcard.  That
effectively adds wildcards in the middle of the minibuffer text
at the start of each "word".  But the first phrase created a
regex which had no such wildcards.  Thus, the two phases could
get substantially different results.

We fix this by changing completion-pcm-leading-wildcard to
consistently add a leading wildcard for each word.  This was
always my intention.

* lisp/minibuffer.el (completion-pcm--string->pattern): Include
a wildcard after each delimter with
completion-pcm-leading-wildcard.
* lisp/minibuffer.el (completion-pcm-leading-wildcard): Update
docs.
* doc/emacs/mini.texi (Completion Styles): Update docs.
---
 doc/emacs/mini.texi |  6 +++---
 lisp/minibuffer.el  | 17 +++++++++--------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/doc/emacs/mini.texi b/doc/emacs/mini.texi
index 0fcd24ed79d..8e0d58d0f7c 100644
--- a/doc/emacs/mini.texi
+++ b/doc/emacs/mini.texi
@@ -577,9 +577,9 @@ Completion Styles
 
 @vindex completion-pcm-leading-wildcard
 If @code{completion-pcm-leading-wildcard} is set to @code{t}, this style
-always acts as if a @dfn{wildcard} is present at the start of the
-minibuffer text, similar to the @code{substring} style.  For example,
-@samp{l-m} will complete to @samp{emacs-lisp-mode}.
+always acts as if a @dfn{wildcard} is present at the start of each word
+in the minibuffer text, similar to the @code{substring} style.  For
+example, @samp{l-ode} will complete to @samp{emacs-lisp-mode}.
 
 @item emacs22
 @cindex @code{emacs22}, completion style
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 2d27fef44ab..cf9ff46e572 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -3996,17 +3996,18 @@ completion-pcm--pattern-trivial-p
 	 trivial)))
 
 (defcustom completion-pcm-leading-wildcard nil
-  "If non-nil, partial-completion completes as if there's a leading wildcard.
+  "If non-nil, partial-completion adds a leading wildcard for each word.
 
-If nil (the default), partial-completion requires a matching completion
-alternative to have the same beginning as the first \"word\" in the
-minibuffer text, where \"word\" is determined by
+If nil (the default), partial-completion requires each word in a
+matching completion alternative to have the same beginning as each
+\"word\" in the minibuffer text, where \"word\" is determined by
 `completion-pcm-word-delimiters'.
 
 If non-nil, partial-completion allows any string of characters to occur
-at the beginning of a completion alternative, as if a wildcard such as
-\"*\" was present at the beginning of the minibuffer text.  This makes
-partial-completion behave more like the substring completion style."
+at the beginning of each word in a completion alternative, as if a
+wildcard such as \"*\" was present at the beginning of each word.  This
+makes partial-completion behave more like the substring completion
+style."
   :version "31.1"
   :type 'boolean)
 
@@ -4053,7 +4054,7 @@ completion-pcm--string->pattern
               (setq p0 p)
             (push (substring string p (match-end 0)) pattern)
             ;; `any-delim' is used so that "a-b" also finds "array->beginning".
-            (setq pending 'any-delim)
+            (setq pending (if completion-pcm-leading-wildcard 'prefix 'any-delim))
             (setq p0 (match-end 0))))
         (setq p p0))
 
-- 
2.39.3