ticket 1669 - improve i18n docstring extraction

This patch reverts the use of pygettext for i18n string extraction. It
was originally introduced because the help documentation for commands
are in the class docstring and module docstring.

Docstrings are a Python construct whereby any string which immediately
follows a class declaration, function/method declaration or appears
first in a module is taken to be the documentation for that
object. Python automatically assigns that string to the __doc__
variable associated with the object. Explicitly assigning to the
__doc__ variable is equivalent and permitted.

We mark strings in the source for i18n translation by embedding them
in _() or ngettext(). Specialized extraction tools (e.g. xgettext)
scan the source code looking for strings with those markers and
extracts the string for inclusion in a translation catalog.

It was mistakingly assumed one could not mark for translation Python
docstrings. Since some docstrings are vital for our command help
system some method had to be devised to extract docstrings for the
translation catalog. pygettext has the ability to locate and extract
docstrings and it was introduced to acquire the documentation for our
commands located in module and class docstrings.

However pygettext was too large a hammer for this task, it lacked any
fined grained ability to extract only the docstrings we were
interested in. In practice it extracted EVERY docstring in each file
it was presented with. This caused a large number strings to be
extracted for translation which had no reason to be translated, the
string might have been internal code documentation never meant to be
seen by users. Often the superfluous docstrings were long, complex and
likely difficult to translate. This placed an unnecessary burden on
our volunteer translators.

Instead what is needed is some method to extract only those strings
intended for translation. We already have such a mechanism and it is
already widely used, namely wrapping strings intended for translation
in calls to _() or _negettext(), i.e. marking a string for i18n
translation. Thus the solution to the docstring translation problem is
to mark the docstrings exactly as we have been doing, it only requires
that instead of a bare Python docstring we instead assign the marked
string to the __doc__ variable. Using the hypothetical class foo as
an example.

class foo(Command):
    '''
    The foo command takes out the garbage.
    '''

Would become:

class foo(Command):
    __doc__ = _('The foo command takes out the garbage.')

But which docstrings need to be marked for translation? The makeapi
tool knows how to iterate over every command in our public API. It was
extended to validate every command's documentation and report if any
documentation is missing or not marked for translation. That
information was then used to identify each docstring in the code which
needed to be transformed.

In summary what this patch does is:

* Remove the use of pygettext (modification to install/po/Makefile.in)

* Replace every docstring with an explicit assignment to __doc__ where
  the rhs of the assignment is an i18n marking function.

* Single line docstrings appearing in multi-line string literals
  (e.g. ''' or """) were replaced with single line string literals
  because the multi-line literals were introducing unnecessary
  whitespace and newlines in the string extracted for translation. For
  example:

  '''
  The foo command takes out the garbage.
  '''

  Would appear in the translation catalog as:

"\n
  The foo command takes out the garbage.\n
  "

  The superfluous whitespace and newlines are confusing to translators
  and requires us to strip leading and trailing whitespace from the
  translation at run time.

* Import statements were moved from below the docstring to above
  it. This was necessary because the i18n markers are imported
  functions and must be available before the the doc is
  parsed. Technically only the import of the i18n markers had to
  appear before the doc but stylistically it's better to keep all the
  imports together.

* It was observed during the docstring editing process that the
  command documentation was inconsistent with respect to the use of
  periods to terminate a sentence. Some doc had a trailing period,
  others didn't. Consistency was enforced by adding a period to end of
  every docstring if one was missing.

1 files changed, 32 insertions, 63 deletions

diff --git a/ipalib/plugins/automount.py b/ipalib/plugins/automount.py
index 6aa3afd0d..1b2214d11 100644
--- a/ipalib/plugins/automount.py
+++ b/ipalib/plugins/automount.py
@@ -17,7 +17,16 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
-"""
+
+from ipalib import api, errors
+from ipalib import Object, Command
+from ipalib import Flag, Str, IA5Str
+from ipalib.plugins.baseldap import *
+from ipalib import _, ngettext
+import ldap as _ldap
+import os
+
+__doc__ = _("""
 Automount
 
 Stores automount(8) configuration for autofs(8) in IPA.
@@ -101,7 +110,7 @@ Keys:
 
   Remove the man key from the auto.share map:
     ipa automountkey-del baltimore auto.share --key=man
-"""
+""")
 
 """
 Developer notes:
@@ -169,13 +178,6 @@ automountInformation: -ro,soft,rsize=8192,wsize=8192 nfs.example.com:/vol/arch
  ive/stuff
 
 """
-from ipalib import api, errors
-from ipalib import Object, Command
-from ipalib import Flag, Str, IA5Str
-from ipalib.plugins.baseldap import *
-from ipalib import _, ngettext
-import ldap as _ldap
-import os
 
 DIRECT_MAP_KEY = u'/-'
 DEFAULT_MAPS = (u'auto.direct', )
@@ -206,9 +208,7 @@ api.register(automountlocation)
 
 
 class automountlocation_add(LDAPCreate):
-    """
-    Create a new automount location.
-    """
+    __doc__ = _('Create a new automount location.')
 
     msg_summary = _('Added automount location "%(value)s"')
 
@@ -229,9 +229,7 @@ api.register(automountlocation_add)
 
 
 class automountlocation_del(LDAPDelete):
-    """
-    Delete an automount location.
-    """
+    __doc__ = _('Delete an automount location.')
 
     msg_summary = _('Deleted automount location "%(value)s"')
 
@@ -239,17 +237,13 @@ api.register(automountlocation_del)
 
 
 class automountlocation_show(LDAPRetrieve):
-    """
-    Display an automount location.
-    """
+    __doc__ = _('Display an automount location.')
 
 api.register(automountlocation_show)
 
 
 class automountlocation_find(LDAPSearch):
-    """
-    Search for an automount location.
-    """
+    __doc__ = _('Search for an automount location.')
 
     msg_summary = ngettext(
         '%(count)d automount location matched',
@@ -260,9 +254,8 @@ api.register(automountlocation_find)
 
 
 class automountlocation_tofiles(LDAPQuery):
-    """
-    Generate automount files for a specific location.
-    """
+    __doc__ = _('Generate automount files for a specific location.')
+
     def execute(self, *args, **options):
         ldap = self.obj.backend
 
@@ -323,9 +316,7 @@ api.register(automountlocation_tofiles)
 
 
 class automountlocation_import(LDAPQuery):
-    """
-    Import automount files for a specific location.
-    """
+    __doc__ = _('Import automount files for a specific location.')
 
     takes_args = (
         Str('masterfile',
@@ -543,9 +534,7 @@ api.register(automountmap)
 
 
 class automountmap_add(LDAPCreate):
-    """
-    Create a new automount map.
-    """
+    __doc__ = _('Create a new automount map.')
 
     msg_summary = _('Added automount map "%(value)s"')
 
@@ -553,9 +542,7 @@ api.register(automountmap_add)
 
 
 class automountmap_del(LDAPDelete):
-    """
-    Delete an automount map.
-    """
+    __doc__ = _('Delete an automount map.')
 
     msg_summary = _('Deleted automount map "%(value)s"')
 
@@ -575,9 +562,7 @@ api.register(automountmap_del)
 
 
 class automountmap_mod(LDAPUpdate):
-    """
-    Modify an automount map.
-    """
+    __doc__ = _('Modify an automount map.')
 
     msg_summary = _('Modified automount map "%(value)s"')
 
@@ -585,9 +570,7 @@ api.register(automountmap_mod)
 
 
 class automountmap_find(LDAPSearch):
-    """
-    Search for an automount map.
-    """
+    __doc__ = _('Search for an automount map.')
 
     msg_summary = ngettext(
         '%(count)d automount map matched',
@@ -598,17 +581,14 @@ api.register(automountmap_find)
 
 
 class automountmap_show(LDAPRetrieve):
-    """
-    Display an automount map.
-    """
+    __doc__ = _('Display an automount map.')
 
 api.register(automountmap_show)
 
 
 class automountkey(LDAPObject):
-    """
-    Automount key object.
-    """
+    __doc__ = _('Automount key object.')
+
     parent_object = 'automountmap'
     container_dn = api.env.container_automount
     object_name = _('automount key')
@@ -753,9 +733,7 @@ api.register(automountkey)
 
 
 class automountkey_add(LDAPCreate):
-    """
-    Create a new automount key.
-    """
+    __doc__ = _('Create a new automount key.')
 
     msg_summary = _('Added automount key "%(value)s"')
 
@@ -780,9 +758,7 @@ api.register(automountkey_add)
 
 
 class automountmap_add_indirect(LDAPCreate):
-    """
-    Create a new indirect mount point.
-    """
+    __doc__ = _('Create a new indirect mount point.')
 
     msg_summary = _('Added automount indirect map "%(value)s"')
 
@@ -818,9 +794,7 @@ api.register(automountmap_add_indirect)
 
 
 class automountkey_del(LDAPDelete):
-    """
-    Delete an automount key.
-    """
+    __doc__ = _('Delete an automount key.')
 
     msg_summary = _('Deleted automount key "%(value)s"')
 
@@ -862,9 +836,7 @@ api.register(automountkey_del)
 
 
 class automountkey_mod(LDAPUpdate):
-    """
-    Modify an automount key.
-    """
+    __doc__ = _('Modify an automount key.')
 
     msg_summary = _('Modified automount key "%(value)s"')
 
@@ -920,9 +892,7 @@ api.register(automountkey_mod)
 
 
 class automountkey_find(LDAPSearch):
-    """
-    Search for an automount key.
-    """
+    __doc__ = _('Search for an automount key.')
 
     msg_summary = ngettext(
         '%(count)d automount key matched',
@@ -933,9 +903,8 @@ api.register(automountkey_find)
 
 
 class automountkey_show(LDAPRetrieve):
-    """
-    Display an automount key.
-    """
+    __doc__ = _('Display an automount key.')
+
     takes_options = LDAPRetrieve.takes_options + (
         IA5Str('automountkey',
                cli_name='key',