[gentoo-portage-dev] [PATCH v2] Support USE_EXPAND prefixes in package.use and relevant files

[Michał Górny]

Support prefixing groups of USE_EXPAND flags with 'USE_EXPAND:' in user
configuration package.use and similar files. This provides a convenient
way of declaring specifying multiple USE_EXPAND flags and matches the
syntax supported by Paludis. Example:

  dev-util/netbeans NETBEANS_MODULES: php webcommon extide
  media-libs/mesa osmesa VIDEO_CARDS: intel nouveau

X-Gentoo-Bug: 471776
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=471776
---
 man/portage.5                                    |  6 ++++++
 pym/portage/package/ebuild/_config/UseManager.py | 24 +++++++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/man/portage.5 b/man/portage.5
index 189561c..5ac3100 100644
--- a/man/portage.5
+++ b/man/portage.5
@@ -792,6 +792,10 @@ documentation for QT.  Easy as pie my friend!
 .nf
 \- comments begin with # (no inline comments)
 \- one DEPEND atom per line with space-delimited USE flags
+\- USE flags can be prefixed with USE_EXPAND name followed by a colon (:)
+and a space. In this case, all the names following it are treated
+as values for the USE_EXPAND. Note that if you need to remove earlier
+assignments or defaults, you need to explicitly specify '\-*'.
 .fi
 
 .I Example:
@@ -800,6 +804,8 @@ documentation for QT.  Easy as pie my friend!
 =x11\-libs/gtk+\-2* doc
 # disable mysql support for QT
 x11\-libs/qt \-mysql
+# set preferred video card for all packages
+*/* VIDEO_CARDS: \-* radeon
 .fi
 .TP
 .BR repos.conf
diff --git a/pym/portage/package/ebuild/_config/UseManager.py b/pym/portage/package/ebuild/_config/UseManager.py
index 3a4ec22..7e235ef 100644
--- a/pym/portage/package/ebuild/_config/UseManager.py
+++ b/pym/portage/package/ebuild/_config/UseManager.py
@@ -145,7 +145,7 @@ class UseManager(object):
 				useflag = prefixed_useflag[1:]
 			else:
 				useflag = prefixed_useflag
-			if useflag_re.match(useflag) is None:
+			if useflag_re.match(prefixed_useflag) is None:
 				writemsg(_("--- Invalid USE flag in '%s': '%s'\n") %
 					(file_name, prefixed_useflag), noiselevel=-1)
 			else:
@@ -202,12 +202,19 @@ class UseManager(object):
 		useflag_re = _get_useflag_re(eapi)
 		for k, v in file_dict.items():
 			useflags = []
+			use_expand_prefix = ''
 			for prefixed_useflag in v:
+				if extended_syntax and prefixed_useflag[-1] == ":":
+					use_expand_prefix = prefixed_useflag[:-1].lower() + "_"
+					continue
+
 				if prefixed_useflag[:1] == "-":
 					useflag = prefixed_useflag[1:]
+					prefixed_useflag = "-" + use_expand_prefix + useflag
 				else:
+					prefixed_useflag = use_expand_prefix + prefixed_useflag
 					useflag = prefixed_useflag
-				if useflag_re.match(useflag) is None:
+				if useflag_re.match(prefixed_useflag) is None:
 					writemsg(_("--- Invalid USE flag for '%s' in '%s': '%s'\n") %
 						(k, file_name, prefixed_useflag), noiselevel=-1)
 				else:
@@ -227,7 +234,18 @@ class UseManager(object):
 			pusedict = grabdict_package(
 				os.path.join(location, file_name), recursive=1, allow_wildcard=True, allow_repo=True, verify_eapi=False)
 			for k, v in pusedict.items():
-				ret.setdefault(k.cp, {})[k] = tuple(v)
+				l = []
+				use_expand_prefix = ''
+				for flag in v:
+					if flag[-1] == ":":
+						use_expand_prefix = flag[:-1].lower() + "_"
+						continue
+					if flag[0] == "-":
+						nv = "-" + use_expand_prefix + flag[1:]
+					else:
+						nv = use_expand_prefix + flag
+					l.append(nv)
+				ret.setdefault(k.cp, {})[k] = tuple(l)
 
 		return ret
 
-- 
2.2.2