Support ${:_profile_base_location_}

Squashed with:

Chomp ../ from beginging of filenames

In order to have as canonical as possible paths,
chomp ../ from filenames and recalculate base.

Squashed with:

fixup! Support ${:_profile_base_location_}

src/zc/buildout/buildout.py

@@ -1824,6 +1824,17 @@ def _default_globals():
 
 variable_template_split = re.compile('([$]{[^}]*})').split
 
+def _normalize_base_and_filename(base, filename):
+  """Chomp ../ from filename and adjust base accordingly
+
+  in order to have as canonical as possible paths"""
+  counter = 0
+  while filename.startswith('../'):
+    filename = filename.replace('../', '', 1)
+    counter += 1
+  base = base.rsplit('/', counter)[0]
+  return base, filename
+
 def _open(
         base, filename, seen, download_options,
         override, downloaded, user_defaults
@@ -1832,6 +1843,7 @@ def _open(
 
     Recursively open other files based on buildout options found.
     """
+    base, filename = _normalize_base_and_filename(base, filename)
     download_options = _update_section(download_options, override)
     raw_download_options = _unannotate_section(download_options)
     newest = bool_option(raw_download_options, 'newest', 'false')
@@ -1893,6 +1905,13 @@ def _open(
             'No-longer supported "extended-by" option found in %s.' %
             filename)
 
+    # find and expose _profile_base_location_
+    for section in result.values():
+        for value in section.values():
+            if '${:_profile_base_location_}' in value:
+                section['_profile_base_location_'] = base
+                break
+
     result = _annotate(result, filename)
 
     if root_config_file and 'buildout' in result:

src/zc/buildout/tests/buildout.txt

@@ -1269,6 +1269,102 @@ the current section.  We can also use the special option,
     my_name debug
     recipe recipes:debug
 
+It is possible to have access to profile base url from section by
+using ${:_profile_base_location_}:
+
+    >>> write(sample_buildout, 'buildout.cfg',
+    ... """
+    ... [buildout]
+    ... develop = recipes
+    ... parts = data-dir debug
+    ... log-level = INFO
+    ...
+    ... [debug]
+    ... recipe = recipes:debug
+    ... profile_base_location = ${:_profile_base_location_}
+    ...
+    ... [data-dir]
+    ... recipe = recipes:mkdir
+    ... path = mydata
+    ... """)
+
+    >>> print_(system(buildout), end='')
+    Develop: '/sample-buildout/recipes'
+    Uninstalling debug.
+    Updating data-dir.
+    Installing debug.
+    _profile_base_location_ /sample-buildout
+    profile_base_location /sample-buildout
+    recipe recipes:debug
+
+Keep in mind that in case of sections spaning across multiple profiles,
+the topmost value will be presented:
+
+    >>> write(sample_buildout, 'extended.cfg',
+    ... """
+    ... [debug]
+    ... profile_base_location = ${:_profile_base_location_}
+    ... """)
+
+    >>> write(sample_buildout, 'buildout.cfg',
+    ... """
+    ... [buildout]
+    ... extends = extended.cfg
+    ... develop = recipes
+    ... parts = data-dir debug
+    ... log-level = INFO
+    ...
+    ... [debug]
+    ... recipe = recipes:debug
+    ... profile_base_location = ${:_profile_base_location_}
+    ...
+    ... [data-dir]
+    ... recipe = recipes:mkdir
+    ... path = mydata
+    ... """)
+
+    >>> print_(system(buildout), end='')
+    Develop: '/sample-buildout/recipes'
+    Updating data-dir.
+    Updating debug.
+    _profile_base_location_ /sample-buildout
+    profile_base_location /sample-buildout
+    recipe recipes:debug
+
+But of course, in case if accessing happens in extended profile's section,
+this profile's location will be exposed:
+
+    >>> write(sample_buildout, 'extended.cfg',
+    ... """
+    ... [debug]
+    ... profile_base_location = ${:_profile_base_location_}
+    ... """)
+
+    >>> write(sample_buildout, 'buildout.cfg',
+    ... """
+    ... [buildout]
+    ... extends = extended.cfg
+    ... develop = recipes
+    ... parts = data-dir debug
+    ... log-level = INFO
+    ...
+    ... [debug]
+    ... recipe = recipes:debug
+    ...
+    ... [data-dir]
+    ... recipe = recipes:mkdir
+    ... path = mydata
+    ... """)
+
+    >>> print_(system(buildout), end='')
+    Develop: '/sample-buildout/recipes'
+    Updating data-dir.
+    Updating debug.
+    _profile_base_location_ /sample-buildout
+    profile_base_location /sample-buildout
+    recipe recipes:debug
+    >>> remove(sample_buildout, 'extended.cfg')
+
 Automatic part selection and ordering
 -------------------------------------
 

src/zc/buildout/tests/extends-cache.txt

@@ -477,12 +477,30 @@ used:
 ... extends = %sbase.cfg
 ... bar = foo
 ... """ % server_url)
+>>> write(server_data, 'baseC.cfg', """\
+... [buildout]
+... extends-cache = cache
+... extends = baseB.cfg
+... bar = foo
+... """)
+>>> write(server_data, 'baseD.cfg', """\
+... [buildout]
+... extends-cache = cache
+... bar = foo
+... """)
+>>> mkdir(server_data, 'deeper')
+>>> write(server_data, 'deeper', 'base.cfg', """\
+... [buildout]
+... extends-cache = cache
+... extends = ../baseD.cfg
+... bar = foo
+... """)
 >>> write('buildout.cfg', """\
 ... [buildout]
 ... extends-cache = cache
 ... newest = true
-... extends = %sbaseA.cfg %sbaseB.cfg
-... """ % (server_url, server_url))
+... extends = %sbaseA.cfg %sbaseB.cfg %sbaseC.cfg %sdeeper/base.cfg
+... """ % (server_url, server_url, server_url, server_url))
 >>> print_(system(buildout + " -n"))
 Section `buildout` contains unused option(s): 'bar' 'foo'.
 This may be an indication for either a typo in the option's name or a bug in the used recipe.
@@ -501,6 +519,10 @@ a better solution would re-use the logging already done by the utility.)
 The URL http://localhost/baseA.cfg was downloaded.
 The URL http://localhost/base.cfg was downloaded.
 The URL http://localhost/baseB.cfg was downloaded.
+The URL http://localhost/baseC.cfg was downloaded.
+The URL http://localhost/baseB.cfg was downloaded.
+The URL http://localhost/deeper/base.cfg was downloaded.
+The URL http://localhost/baseD.cfg was downloaded.
 Not upgrading because not running a local buildout command.
 Section `buildout` contains unused option(s): 'bar' 'foo'.
 This may be an indication for either a typo in the option's name or a bug in the used recipe.