git@vger.kernel.org mailing list mirror (one of many)
 help / Atom feed
From: Stefan Beller <sbeller@google.com>
To: Jeff King <peff@peff.net>
Cc: "git@vger.kernel.org" <git@vger.kernel.org>,
	Orgad Shaneh <orgads@gmail.com>
Subject: Re: [PATCH] diff.c: increment buffer pointer in all code path
Date: Thu, 19 Oct 2017 12:53:03 -0700
Message-ID: <CAGZ79kbRFVd=hbc4DCrdkOJ4aUE_g1_NhMbG-tfPGnOJikf1GA@mail.gmail.com> (raw)
In-Reply-To: <20171019052457.gqenoshgyjcw53tb@sigill.intra.peff.net>

On Wed, Oct 18, 2017 at 10:24 PM, Jeff King <peff@peff.net> wrote:
> On Thu, Oct 19, 2017 at 01:04:59AM -0400, Jeff King wrote:
>
>> So. That leaves me with:
>>
>>   - I'm unclear on whether next_byte() is meant to return that trailing
>>     NUL or not. I don't think it causes any bugs, but it certainly
>>     confused me for a function to take a cp/endp pair of pointers, and
>>     then dereference endp. It might be worth either fixing or clarifying
>>     with a comment.
>>
>>   - Those loops to eat trailing whitespace are doing nothing. I'm not
>>     sure if that all works out because next_byte() eats whitespaces or
>>     not (I think not, because it doesn't eat whitespace for the
>>     IGNORE_WHITESPACE_AT_EOL case). But I'm not quite sure what a test
>>     would look like.
>
> I had trouble constructing a test at first, but I think my test lines
> just weren't long enough to trigger the movement heuristics. If I switch
> to something besides seq, I can do:
>
>   # any input that has reasonably sized lines
>   look e | head -50 >file
>   git add file
>
>   perl -i -ne '
>     # pick up lines 20-25 to move to line 40, and
>     # add some trailing whitespace to them
>     if ($. >= 20 && $. <= 25) {
>       s/$/     /;
>       $hold .= $_;
>     } else {
>       print $hold if ($. == 40);
>       print;
>     }
>   ' file
>
>   git diff --color-moved --ignore-space-at-eol
>
> I think that _should_ show the block as moved, but it doesn't. But if I
> apply this patch:
>
> diff --git a/diff.c b/diff.c
> index 93dccd1817..375d9cf447 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -743,8 +743,8 @@ static int moved_entry_cmp(const struct diff_options *diffopt,
>                            const struct moved_entry *b,
>                            const void *keydata)
>  {
> -       const char *ap = a->es->line, *ae = a->es->line + a->es->len;
> -       const char *bp = b->es->line, *be = b->es->line + b->es->len;
> +       const char *ap = a->es->line, *ae = a->es->line + a->es->len - 1;
> +       const char *bp = b->es->line, *be = b->es->line + b->es->len - 1;
>
>         if (!(diffopt->xdl_opts & XDF_WHITESPACE_FLAGS))
>                 return a->es->len != b->es->len  || memcmp(ap, bp, a->es->len);
> @@ -771,7 +771,7 @@ static unsigned get_string_hash(struct emitted_diff_symbol *es, struct diff_opti
>  {
>         if (o->xdl_opts & XDF_WHITESPACE_FLAGS) {
>                 static struct strbuf sb = STRBUF_INIT;
> -               const char *ap = es->line, *ae = es->line + es->len;
> +               const char *ap = es->line, *ae = es->line + es->len - 1;
>                 int c;
>
>                 strbuf_reset(&sb);
>
> it does. It just adjusts our "end pointer" to point to the last valid
> character in the string (rather than one past),

Thanks for spotting. I can send a proper patch with tests if you'd like.


> which seems to be the
> convention that those loops (and next_byte) expect.

I'll look at that again.

Thanks for poking!
Stefan

>
> -Peff

  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-12 19:53 Out of memory with diff.colormoved enabled Orgad Shaneh
2017-10-12 20:05 ` Jeff King
2017-10-12 22:39   ` Stefan Beller
2017-10-12 23:33   ` [PATCH] diff.c: increment buffer pointer in all code path Stefan Beller
2017-10-13  0:18     ` Jeff King
2017-10-13  0:20       ` Jeff King
2017-10-13  0:24         ` Stefan Beller
2017-10-19  5:04         ` Jeff King
2017-10-19  5:24           ` Jeff King
2017-10-19  5:30             ` Junio C Hamano
2017-10-19  5:32               ` Junio C Hamano
2017-10-19  5:32                 ` Jeff King
2017-10-19  5:42               ` Jeff King
2017-10-19 19:55                 ` Stefan Beller
2017-10-19 20:23                 ` [PATCH 0/5] fix "diff --color-moved --ignore-space-at-eol" Jeff King
2017-10-19 20:24                   ` [PATCH 1/5] t4015: refactor --color-moved whitespace test Jeff King
2017-10-19 20:56                     ` Stefan Beller
2017-10-19 21:10                       ` Jeff King
2017-10-19 20:25                   ` [PATCH 2/5] t4015: check "negative" case for "-w --color-moved" Jeff King
2017-10-19 20:54                     ` Stefan Beller
2017-10-19 20:26                   ` [PATCH 3/5] t4015: test the output of "diff --color-moved -b" Jeff King
2017-10-19 21:03                     ` Stefan Beller
2017-10-19 21:14                       ` Jeff King
2017-10-19 20:29                   ` [PATCH 4/5] diff: fix whitespace-skipping with --color-moved Jeff King
2017-10-19 21:15                     ` Stefan Beller
2017-10-19 21:19                       ` Jeff King
2017-10-20  7:23                     ` Simon Ruderich
2017-10-20 22:37                       ` Jeff King
2017-10-19 20:31                   ` [PATCH 5/5] diff: handle NULs in get_string_hash() Jeff King
2017-10-19 21:31                     ` Stefan Beller
2017-10-19 21:39                       ` Jeff King
2017-10-19 21:50                         ` Stefan Beller
2017-10-19 19:53             ` Stefan Beller [this message]
2017-10-19 19:55               ` [PATCH] diff.c: increment buffer pointer in all code path Jeff King

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAGZ79kbRFVd=hbc4DCrdkOJ4aUE_g1_NhMbG-tfPGnOJikf1GA@mail.gmail.com' \
    --to=sbeller@google.com \
    --cc=git@vger.kernel.org \
    --cc=orgads@gmail.com \
    --cc=peff@peff.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

git@vger.kernel.org mailing list mirror (one of many)

Archives are clonable:
	git clone --mirror https://public-inbox.org/git
	git clone --mirror http://ou63pmih66umazou.onion/git
	git clone --mirror http://czquwvybam4bgbro.onion/git
	git clone --mirror http://hjrcffqmbrq6wope.onion/git

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.version-control.git
	nntp://ou63pmih66umazou.onion/inbox.comp.version-control.git
	nntp://czquwvybam4bgbro.onion/inbox.comp.version-control.git
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.version-control.git
	nntp://news.gmane.org/gmane.comp.version-control.git

 note: .onion URLs require Tor: https://www.torproject.org/
       or Tor2web: https://www.tor2web.org/

AGPL code for this site: git clone https://public-inbox.org/ public-inbox