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

[Austin Clements]

LGTM!

Quoth Mark Walters on Aug 08 at 10:23 pm:
> 
> 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 is the same as id:"874noe1o0r.fsf at qmul.ac.uk" except for being
> based on top of the test in the parent message, and marking the broken
> test fixed.
> 
> Best wishes
> 
> Mark
> 
>  sprinter-json.c      |    2 ++
>  sprinter-text.c      |    2 ++
>  sprinter.h           |    4 +++-
>  test/missing-headers |    2 --
>  4 files changed, 7 insertions(+), 3 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);
> diff --git a/test/missing-headers b/test/missing-headers
> index e79f922..f14b878 100755
> --- a/test/missing-headers
> +++ b/test/missing-headers
> @@ -29,7 +29,6 @@ thread:XXX   2001-01-05 [1/1] (null);  (inbox unread)
>  thread:XXX   1970-01-01 [1/1] Notmuch Test Suite;  (inbox unread)"
>  
>  test_begin_subtest "Search: json"
> -test_subtest_known_broken
>  output=$(notmuch search --format=json '*' | notmuch_search_sanitize)
>  test_expect_equal_json "$output" '
>  [
> @@ -93,7 +92,6 @@ Body
>  message}"
>  
>  test_begin_subtest "Show: json"
> -test_subtest_known_broken
>  output=$(notmuch show --format=json '*' | notmuch_json_show_sanitize)
>  test_expect_equal_json "$output" '
>  [