Re: [PATCH] strbuf: change an always NULL/"" strbuf_addftime() param to bool

From: Jeff King <peff@peff.net>
Date: Jun 23, 2017, 14:51 UTC
Message-ID: <20170623145102.h7rt6zaqajfzuhsk@sigill.intra.peff.net>
In-Reply-To: <20170623144603.11774-1-avarab@gmail.com>

On Fri, Jun 23, 2017 at 02:46:03PM +0000, Ævar Arnfjörð Bjarmason wrote:

Show 12 quoted lines

> Change the code for deciding what's to be done about %Z to stop
> passing always either a NULL or "" char * to
> strbuf_addftime(). Instead pass a boolean int to indicate whether the
> strftime() %Z format should be omitted, which is what this code is
> actually doing.
> 
> This code grew organically between the changes in 9eafe86d58 ("Merge
> branch 'rs/strbuf-addftime-zZ'", 2017-06-22) yielding an end result
> that wasn't very readable. Out of context it looked as though the call
> to strbuf_addstr() might be adding a custom tz_name to the string, but
> actually tz_name would always be "", so the call to strbuf_addstr()
> just to add an empty string to the format was pointless.

The idea was that eventually the caller might be able to come up with a TZ that is not blank, but is also not what strftime("%Z") would produce. Conceivably that could be done if Git commits carried the "%Z" information (not likely), or if we used a reverse-lookup table (also not likely).

This closes the door on that. Since we don't have immediate plans to go that route, I'm OK with this patch. It would be easy enough to re-open the door if we change our minds later.

Show 8 quoted lines

>  /**
>   * Add the time specified by `tm`, as formatted by `strftime`.
> - * `tz_name` is used to expand %Z internally unless it's NULL.
>   * `tz_offset` is in decimal hhmm format, e.g. -600 means six hours west
>   * of Greenwich, and it's used to expand %z internally.  However, tokens
>   * with modifiers (e.g. %Ez) are passed to `strftime`.
> + * `omit_strftime_tz_name` when set, means don't let `strftime` format
> + * %Z, instead do our own formatting.

Since we now always turn it into a blank string, perhaps "do our own formatting" could be more descriptive: we convert it into the empty string.

-Peff