bug#28615: 25.3; rgrep, grep-read-files confusingly completes file names

bug#28615: 25.3; rgrep, grep-read-files confusingly completes file names

[ヌエルモリノ]

rgrep uses grep-read-files to read a filename as the second argument.
However, rgrep cannot actually accept a filename as the second argument.

For example, this is a normal rgrep call

  (rgrep "foo" "*.el" "/some/dir/" nil)

"*.el" is read with grep-read-files, which uses filename completion.
However, actually entering a filename doesn’t really work

  (rgrep "foo" "foo/*.el" "/some/dir/" nil)
  (rgrep "foo" "foo/bar.el" "/some/dir/" nil)

The second argument is passed to the find program as an -iname argument
as a glob, which matches against strictly the filename (e.g., like
file-name-nondirectory) and not the path.

There are a few points that could be improved here.

1. The grep-read-files prompt is confusing.  The prompt is: "Search for
\"foo\" in files: ".  It is not clear that this is asking for a filename
glob.

2. grep-read-files uses filename completion, which suggests that the
user should enter a filename.  This is very misleading as most paths
will fail to work, passing a filename without a slash will likely not
work as the user would expect, and almost certainly a glob would be the
desired input.

In GNU Emacs 25.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.19)
 of 2017-09-16 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.11903000
Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-modules
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong
 -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

bug#28615: [PATCH] Clarify what grep-read-files wants

[Allen Li]

grep-read-files wants a filename glob, not a filename/path.

* lisp/progmodes/grep.el (grep-read-files): Clarify docstring.
  Use file aliases for completion.
  Clarify completing-read prompt.
---
 lisp/progmodes/grep.el | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lisp/progmodes/grep.el b/lisp/progmodes/grep.el
index 01bdb04714..0537c76d30 100644
--- a/lisp/progmodes/grep.el
+++ b/lisp/progmodes/grep.el
@@ -903,7 +903,7 @@ grep-read-regexp
   (read-regexp "Search for" 'grep-tag-default 'grep-regexp-history))

 (defun grep-read-files (regexp)
-  "Read files arg for interactive grep."
+  "Read filename glob arg for interactive grep."
   (let* ((bn (or (buffer-file-name)
  (replace-regexp-in-string "<[0-9]+>\\'" "" (buffer-name))))
  (fn (and bn
@@ -936,10 +936,10 @@ grep-read-files
         (car (car grep-files-aliases))))
  (files (completing-read
  (concat "Search for \"" regexp
- "\" in files"
+ "\" in files matching glob"
  (if default (concat " (default " default ")"))
  ": ")
- 'read-file-name-internal
+ grep-files-aliases
  nil nil nil 'grep-files-history
  (delete-dups
    (delq nil (append (list default default-alias default-extension)
-- 
2.14.2

bug#28615: [PATCH] Clarify what grep-read-files wants

[Eli Zaretskii]

> From: Allen Li <vianchielfaura@gmail.com>
> Date: Wed, 4 Oct 2017 21:15:32 -0700
> 
> grep-read-files wants a filename glob, not a filename/path.
> 
> * lisp/progmodes/grep.el (grep-read-files): Clarify docstring.
>   Use file aliases for completion.
>   Clarify completing-read prompt.

Thanks, I installed a slightly different change for the first 2 parts,
but didn't change the function we pass to completing-read.

With that, I'm closing the bug report.

bug#28615: [PATCH] Clarify what grep-read-files wants

[Allen Li]

On Mon, Oct 9, 2017 at 6:41 AM, Eli Zaretskii <eliz@gnu.org> wrote:
>
> Thanks, I installed a slightly different change for the first 2 parts,
> but didn't change the function we pass to completing-read.
>
> With that, I'm closing the bug report.

Why did you not change the collection function?  As I noted in the
bug, most of the completions that would be provided by
read-file-name-internal don't work, and the ones that do work result
in running rgrep against a single file.  grep-files-aliases seems like
a much better choice than read-file-name-internal, given that
grep-files-aliases is intended to provide aliases for this very
purpose.

bug#28615: [PATCH] Clarify what grep-read-files wants

[Eli Zaretskii]

> From: Allen Li <vianchielfaura@gmail.com>
> Date: Mon, 9 Oct 2017 21:43:59 -0700
> Cc: 28615-done@debbugs.gnu.org
> 
> Why did you not change the collection function?

Because there could be a file called literally like one of the
shorthands in grep-files-aliases, or whose name includes those
shorthands as a substring.

> As I noted in the bug, most of the completions that would be
> provided by read-file-name-internal don't work

IMO, that's okay, because wildcards cannot be meaningfully completed
on.

bug#28615: [PATCH] Clarify what grep-read-files wants

[Allen Li]

On Mon, Oct 9, 2017 at 10:55 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Allen Li <vianchielfaura@gmail.com>
>> Date: Mon, 9 Oct 2017 21:43:59 -0700
>> Cc: 28615-done@debbugs.gnu.org
>>
>> Why did you not change the collection function?
>
> Because there could be a file called literally like one of the
> shorthands in grep-files-aliases, or whose name includes those
> shorthands as a substring.

Not sure what you mean.  There is no use case for completing a
file name.  Are you saying that a user might mistake the completion
on grep-files-aliases as completion on file name?  I believe that
with the new prompt change, that is unlikely.

>
>> As I noted in the bug, most of the completions that would be
>> provided by read-file-name-internal don't work
>
> IMO, that's okay, because wildcards cannot be meaningfully completed
> on.

But the aliases from grep-files-aliases can be meaningfully
completed.  I don't see why we shouldn't provide meaningful
completion if the user defines a lot of aliases, seeing as how
the current file name completion is useless.

bug#28615: [PATCH] Clarify what grep-read-files wants

[Eli Zaretskii]

> From: Allen Li <vianchielfaura@gmail.com>
> Date: Mon, 9 Oct 2017 23:51:47 -0700
> Cc: 28615@debbugs.gnu.org
> 
> Are you saying that a user might mistake the completion on
> grep-files-aliases as completion on file name?

Something like that, yes.  In general, I don't think completing on
wildcards is useful.

> I believe that with the new prompt change, that is unlikely.

People don't always read the prompt paying attention to every word of
it, and "all" is a valid wildcard anyway.

> >> As I noted in the bug, most of the completions that would be
> >> provided by read-file-name-internal don't work
> >
> > IMO, that's okay, because wildcards cannot be meaningfully completed
> > on.
> 
> But the aliases from grep-files-aliases can be meaningfully
> completed.  I don't see why we shouldn't provide meaningful
> completion if the user defines a lot of aliases, seeing as how
> the current file name completion is useless.

I didn't think allowing it to complete on 2 non-file values is
important enough to justify the possible confusion.