[PATCH] util: use string.hexdigits instead of defining it ourselves

[Martijn Pieters]

On 7 October 2016 at 15:14, Augie Fackler <raf at durin42.com> wrote:

> Yeah. I went with this because it seems silly to have our own version of
> the constant when Python already has one that is the right type.
>

There is more silliness.

The whole unquote function duplicates the one in the Python stdlib, from
2.4 somewhere, because it improved perf to not have to import urllib,
see c285bdb0572a48a34c9669a549793e60b5a469d4:

    util.url: copy urllib.unquote() into util to improve startup times

However, Python has since moved this function to urlparse in 2.6 (much
smaller module, so no perf reason anymore), the hex-digits dictionary is
build lazily in Python 3, and *most importantly*, those versions avoid the
quadratic performance behaviour of the 2.4 version we copied into Mercurial
(string building with += that evades the CPython optimisation for string
concatenation because multiple strings are being concatenated in each
expression).

So what *really* needs to happen is splitting out the `url` class out to a
new module (so it is used from fewer places and not always imported) and
then the stdlib unquote should be used again.

I'll see about creating a patch for this.

-- 
Martijn Pieters
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