From: Daniel Shahaf <d.s@daniel.shahaf.name>
To: zsh-workers@zsh.org
Subject: Re: [PATCH] New :P history modifier.
Date: Wed, 17 Aug 2016 16:31:41 +0000 [thread overview]
Message-ID: <20160817163141.GB9003@tarsus.local2> (raw)
In-Reply-To: <160817000240.ZM19759@torch.brasslantern.com>
Bart Schaefer wrote on Wed, Aug 17, 2016 at 00:02:40 -0700:
> On Aug 16, 11:54pm, Daniel Shahaf wrote:
> }
> } WDYT?
>
> The code changes are essentially OK; my only thought is, maybe we
> should just remove the dependency on the POSIX realpath() call even
> from :A, and use xsymlink() everywhere?
>
Two thoughts:
- Does anyone actually build zsh on a system that doesn't have realpath()?
- xsymlink() is not a drop-in replacement: it tolerates trailing
non-existing path components. The single callsite in current master
wouldn't care, though.
> Picking at the docs ...
>
> Given that we went to the trouble of hashing it out, it is probably
> worth noting that :a is intended to result in the path to along which
> "cd" would change under the default setopts (no_chase_dots),
38945 made such a change; do you think further changes are needed?
> and :A is meant to result in the physical directory at the end of that
> path.
No wording comes to mind, here.
>
> } + "a:absolute path, resolve '..' logically"
> } + "A:same, then resolve symlinks"
> } + "P:realpath, resolve '..' physically"
>
> I'm not sure "logical" and "physical"
> are the right words here, but "by text replacement" and "by filesystem
> reference" seem a bit too verbose, so I don't have a suggestion, just
> calling attention.
They might work as parentheticals: "a:... logically (by text
replacement)" and "P:... physically (by filesystem lookup)"?
Some other options:
- :a syntactically / lexically / "like 'cd'"
- :P semantically / "like stat(2)"
(yes, "like 'cd'" is inaccurate if CHASE_* are set)
> You should spell out what "same" means, because the two descriptions
> may not always appear together.
I'll change "same" to "as ':a'".
I wonder if there's a way to make the :A completion text convey "Unless
you're trying to predict what 'cd' is about to do, you probably want :P,
not :A"...
> } +The new word modifier ':P' computes the realpath() of the argument.
> } +It is different from the existing ':a' modifier which does not resolve
> } +symlinks, and from the existing ':A' modifier which always resolves
> ^^^^^^^^
>
> If you're going to compare to both :a and :A, symlinks aren't the largest
> difference vs. :a -- following ".." is. In fact I'd say following ".."
> is more important to the distinction than symlinks are.
>
> } +/before/here/../after to /before/after --- even if /before/here is
> } +a symbolic link. It is recommended to review uses of ':A' and, if
> } +appropriate, convert them to ':P' as soon as compatibility with 5.2 is
> } +no longer a requirement.
>
> So how about e.g.:
>
> The new word modifier ':P' computes the physical path of the argument.
> it is different from the existing ':a' modifier which does always
> resolves /before/here/../after to /before/after, and differs from the
> existing ':A' modifier which resolves symlinks only after here/.. is
> removed even when /before/here is itself a symbolic link.
>
Looks good to me.
What about the "It is recommended [to audit uses of :A and change them
to :P]" sentence that the original patch had, should it be kept or
removed?
> That's all.
Thanks for the review!
Daniel
next prev parent reply other threads:[~2016-08-17 16:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-16 23:54 Daniel Shahaf
2016-08-17 7:02 ` Bart Schaefer
2016-08-17 16:31 ` Daniel Shahaf [this message]
2016-08-17 17:06 ` Bart Schaefer
2016-08-18 16:55 ` Daniel Shahaf
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