[#614] add towncrier to manage changelog additions

[gaborbernat]

• also moved Let skip_install override usedevelop instead of the other way around #571 documentation to news fragment as demonstration
• extended the documentation build to automatically prepend the current new fragments to the changelog, this way news fragments are also subject to the CI operations, but otherwise when we do a release (and there are no news staged don't get in the way)

[obestwalter]

LGTM let's start using it :)

[codecov]

Codecov Report

Merging #615 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #615   +/-   ##
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  Coverage   92.38%   92.38%           
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  Files          11       11           
  Lines        2391     2391           
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  Hits         2209     2209           
  Misses        182      182

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[gaborbernat]

hmmm, still WIP, I need to elevate the header level first

[obestwalter]

the whaddy what what? o.k. go ahead, I have no clue yet how it really works :)

[gaborbernat]

Ok now should be fine; let's wait for the CI to confirm this.

The problem was that now we generate an additional level of headers by town crier, the four big groups. towncrier uses for this level 2 (-), but for us the version numbers were already level 2. So in order to have the correct hierarchy the version numbers in the changelog now are level 1, as it's done in pytest (see https://raw.githubusercontent.com/pytest-dev/pytest/master/CHANGELOG.rst).

[obestwalter]

Great. I am really looking forward to start using this. The manual way was a major PITA.

... and it will look much nicer wherever we put this.

One thing I just thought of: the little helper I built to generate the long description is not needed anymore then:

tox/setup.py

Lines 41 to 63 in 952385a

	def get_linked_changelog(here, n=5):
	"""changelog containing last n releases with links to issues"""
	repo_url = 'https://github.com/tox-dev/tox'
	changelog_url = '%s/blob/master/CHANGELOG' % repo_url
	with io.open(os.path.join(here, 'CHANGELOG'), encoding='utf-8') as f:
	changelog = f.read()
	header_matches = list(re.finditer('^-+$', changelog, re.MULTILINE))
	lines = changelog[:header_matches[n].start()].splitlines()[:-1]
	title = "Changelog (last %s releases - `full changelog <%s>`_)" % (
	n, changelog_url)
	changelog = '\n'.join([title, '=' * len(title), "\n", "\n".join(lines)])
	issue_replacement = r'`#\1 <%s/issues/\1>`_' % repo_url
	for pattern in [r'#(\d+)', r'issue(\d+)']:
	changelog = re.sub(pattern, issue_replacement, changelog)
	pull_replacement = r'`#p\1 <%s/pull/\1>`_' % repo_url
	changelog = re.sub(r'#p(\d+)', pull_replacement, changelog)
	return changelog
	def get_long_description():
	here = os.path.abspath('.')
	with io.open(os.path.join(here, 'README.rst'), encoding='utf-8') as f:
	return "%s\n\n%s" % (f.read(), get_linked_changelog(here))

We should get rid of that right away, before we forget that it' obsolete :)

[obestwalter]

would be something like that then:

def get_long_description(): 
     here = os.path.abspath('.') 
     with io.open(os.path.join(here, 'README.rst'), encoding='utf-8') as f: 
        with io.open(os.path.join(here, 'CHANGELOG.rst'), encoding='utf-8') as g: 
            return "%s\n\n%s" % (f.read(), g.read()) 

[gaborbernat]

@obestwalter there's a filtering step in there, like taking last 5 releases which you removed; but otherwise true 👍

[obestwalter]

changed it in branch (hopefully did not mess it up, did it in web editor).

[obestwalter]

full changelog is o.k. I guess.

[obestwalter]

otherwise, we can readd it later, just want to makw sure we git rid of old busted stuff right away

[RonnyPfannschmidt]

towncrier uses calver, so that version block is not sensible

[gaborbernat]

true, will remove it!

[obestwalter]

mac is awfully slow these days. Anyway let's merge this.

[The-Compiler]

Yeah, Travis had some issues: https://www.traviscistatus.com/