From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Cc: git@vger.kernel.org, gitster@pobox.com, hi-angel@yandex.ru,
peff@peff.net, ramsay@ramsayjones.plus.com,
sunshine@sunshineco.com
Subject: Re: [PATCH v5 1/1] worktree add: sanitize worktree names
Date: Mon, 11 Mar 2019 14:05:32 +0100 (STD) [thread overview]
Message-ID: <nycvar.QRO.7.76.6.1903111401220.41@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20190308092834.12549-2-pclouds@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 3151 bytes --]
Hi Duy,
On Fri, 8 Mar 2019, Nguyễn Thái Ngọc Duy wrote:
> diff --git a/refs.c b/refs.c
> index 142888a40a..e9f83018f0 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -72,30 +72,57 @@ static unsigned char refname_disposition[256] = {
> * - it ends with ".lock", or
> * - it contains a "@{" portion
> */
> -static int check_refname_component(const char *refname, int *flags)
> +static int check_refname_component(const char *refname, int *flags,
> + struct strbuf *sanitized)
> {
> const char *cp;
> char last = '\0';
> + size_t component_start;
This variable is uninitialized. It is then...
> +
> + if (sanitized)
> + component_start = sanitized->len;
... initialized only when `sanitized` is not `NULL`, and subsequently...
>
> for (cp = refname; ; cp++) {
> int ch = *cp & 255;
> unsigned char disp = refname_disposition[ch];
> +
> + if (sanitized && disp != 1)
> + strbuf_addch(sanitized, ch);
> +
> switch (disp) {
> case 1:
> goto out;
> case 2:
> - if (last == '.')
> - return -1; /* Refname contains "..". */
> + if (last == '.') { /* Refname contains "..". */
> + if (sanitized)
> + sanitized->len--; /* collapse ".." to single "." */
> + else
> + return -1;
> + }
> break;
> case 3:
> - if (last == '@')
> - return -1; /* Refname contains "@{". */
> + if (last == '@') { /* Refname contains "@{". */
> + if (sanitized)
> + sanitized->buf[sanitized->len-1] = '-';
> + else
> + return -1;
> + }
> break;
> case 4:
> - return -1;
> + /* forbidden char */
> + if (sanitized)
> + sanitized->buf[sanitized->len-1] = '-';
> + else
> + return -1;
> + break;
> case 5:
> - if (!(*flags & REFNAME_REFSPEC_PATTERN))
> - return -1; /* refspec can't be a pattern */
> + if (!(*flags & REFNAME_REFSPEC_PATTERN)) {
> + /* refspec can't be a pattern */
> + if (sanitized)
> + sanitized->buf[sanitized->len-1] = '-';
> + else
> + return -1;
> + }
>
> /*
> * Unset the pattern flag so that we only accept
> @@ -109,26 +136,48 @@ static int check_refname_component(const char *refname, int *flags)
> out:
> if (cp == refname)
> return 0; /* Component has zero length. */
> - if (refname[0] == '.')
> - return -1; /* Component starts with '.'. */
> +
> + if (refname[0] == '.') { /* Component starts with '.'. */
> + if (sanitized)
> + sanitized->buf[component_start] = '-';
... used a loooooooong time after that, also only if `sanitized` is not
`NULL`.
Apparently for some GCC versions, this is too cute, and it complains that
this variable might be used uninitialized:
https://dev.azure.com/gitgitgadget/git/_build/results?buildId=4352&view=logs
And quite honestly, even for mere humans it is not all *that* clear that
`sanitized` cannot be changed from `NULL` to non-`NULL` in the code in
between, *in particular* because the changes extend over two hunks, the
code between is not shown.
I would strongly advise against trying to be so cute, and just initialize
the variable already. Over-optimization in such instances makes the code a
lot harder to reason about.
Ciao,
Johannes
next prev parent reply other threads:[~2019-03-11 13:06 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-18 14:36 git gc fails with "unable to resolve reference" for worktree hi-angel
2019-02-18 15:02 ` Duy Nguyen
2019-02-18 15:09 ` hi-angel
2019-02-18 15:18 ` Duy Nguyen
2019-02-20 14:34 ` hi-angel
2019-02-21 11:00 ` [PATCH] worktree add: sanitize worktree names Nguyễn Thái Ngọc Duy
2019-02-21 11:28 ` Konstantin Kharlamov
2019-02-21 11:38 ` Duy Nguyen
2019-02-21 11:44 ` Konstantin Kharlamov
2019-02-21 11:52 ` Duy Nguyen
2019-02-21 13:23 ` Jeff King
2019-02-21 12:19 ` [PATCH v2 0/1] " Nguyễn Thái Ngọc Duy
2019-02-21 12:19 ` [PATCH v2 1/1] " Nguyễn Thái Ngọc Duy
2019-02-21 13:22 ` Jeff King
2019-02-21 17:41 ` Ramsay Jones
2019-02-22 9:21 ` Duy Nguyen
2019-02-26 10:58 ` [PATCH v3 0/1] " Nguyễn Thái Ngọc Duy
2019-02-26 10:58 ` [PATCH v3 1/1] " Nguyễn Thái Ngọc Duy
2019-02-27 12:08 ` Jeff King
2019-02-27 14:23 ` Eric Sunshine
2019-02-27 16:04 ` Jeff King
2019-03-03 1:22 ` Junio C Hamano
2019-03-04 11:19 ` Duy Nguyen
2019-03-04 12:04 ` Duy Nguyen
2019-03-04 15:06 ` Johannes Schindelin
2019-03-05 12:08 ` [PATCH v4 0/2] " Nguyễn Thái Ngọc Duy
2019-03-05 12:08 ` [PATCH v4 1/2] refs.c: refactor check_refname_component() Nguyễn Thái Ngọc Duy
2019-03-06 21:49 ` Jeff King
2019-03-07 23:24 ` Eric Sunshine
2019-03-05 12:08 ` [PATCH v4 2/2] worktree add: sanitize worktree names Nguyễn Thái Ngọc Duy
2019-03-08 9:28 ` [PATCH v5 0/1] " Nguyễn Thái Ngọc Duy
2019-03-08 9:28 ` [PATCH v5 1/1] " Nguyễn Thái Ngọc Duy
2019-03-10 2:02 ` Eric Sunshine
2019-03-11 6:20 ` Junio C Hamano
2019-03-11 9:24 ` Duy Nguyen
2019-03-11 22:39 ` Jeff King
2019-03-12 6:32 ` Junio C Hamano
2019-03-11 6:36 ` Junio C Hamano
2019-03-11 9:27 ` Duy Nguyen
2019-03-11 13:05 ` Johannes Schindelin [this message]
2019-03-12 6:45 ` Junio C Hamano
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