[PATCH] sprinters: bugfix when NULL passed for a string.

[Austin Clements]

LGTM.

This won't commute with [0], since that introduces broken tests that are
fixed by this patch.

I think we should remove the fields in the JSON header object for
missing headers (except perhaps From and Date, if those really are
mandatory headers), but I think we should do that after the freeze,
since it might affect frontends.  It probably makes sense to add an
Emacs test or two to the tests in [0].

[0] id:"1344389313-7886-1-git-send-email-amdragon at mit.edu"

On Tue, 07 Aug 2012, Mark Walters <markwalters1009 at gmail.com> wrote:
> The string function in a sprinter may be called with a NULL string
> pointer (eg if a header is absent). This causes a segfault. We fix
> this by checking for a null pointer in the string functions and update
> the sprinter documentation.
>
> At the moment some output when format=text is done directly rather than
> via an sprinter: in that case a null pointer is passed to printf or
> similar and a "(null)" appears in the output. That behaviour is not
> changed in this patch.
> ---
>
> This could really do with some tests (it is the second time this type of
> bug has occurred). To be considered as a message by notmuch new a file
> needs at least one of a From: Subject: or To: header. Thus we should
> have three messages each of which just contains that single header (and
> nothing else) and check that search and show work as expected. 
>
>
>
>  sprinter-json.c |    2 ++
>  sprinter-text.c |    2 ++
>  sprinter.h      |    4 +++-
>  3 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/sprinter-json.c b/sprinter-json.c
> index c9b6835..0a07790 100644
> --- a/sprinter-json.c
> +++ b/sprinter-json.c
> @@ -118,6 +118,8 @@ json_string_len (struct sprinter *sp, const char *val, size_t len)
>  static void
>  json_string (struct sprinter *sp, const char *val)
>  {
> +    if (val == NULL)
> +	val = "";
>      json_string_len (sp, val, strlen (val));
>  }
>  
> diff --git a/sprinter-text.c b/sprinter-text.c
> index dfa54b5..10343be 100644
> --- a/sprinter-text.c
> +++ b/sprinter-text.c
> @@ -38,6 +38,8 @@ text_string_len (struct sprinter *sp, const char *val, size_t len)
>  static void
>  text_string (struct sprinter *sp, const char *val)
>  {
> +    if (val == NULL)
> +	val = "";
>      text_string_len (sp, val, strlen (val));
>  }
>  
> diff --git a/sprinter.h b/sprinter.h
> index 5f43175..912a526 100644
> --- a/sprinter.h
> +++ b/sprinter.h
> @@ -27,7 +27,9 @@ typedef struct sprinter {
>       * a list or map, followed or preceded by separators).  For string
>       * and string_len, the char * must be UTF-8 encoded.  string_len
>       * allows non-terminated strings and strings with embedded NULs
> -     * (though the handling of the latter is format-dependent).
> +     * (though the handling of the latter is format-dependent). For
> +     * string (but not string_len) the string pointer passed may be
> +     * NULL.
>       */
>      void (*string) (struct sprinter *, const char *);
>      void (*string_len) (struct sprinter *, const char *, size_t);
> -- 
> 1.7.9.1
>
>
> H
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