[gentoo-portage-dev] [PATCH] egencache --update-pkg-desc-index: handle read-only repo (bug 549616)

[Zac Medico]

If the repo is read-only, write the cache to /var/cache/edb/dep
where IndexedPortdb searches for it.

X-Gentoo-Bug: 549616
X-Gentoo-Bug-url: https://bugs.gentoo.org/show_bug.cgi?id=549616
---
 bin/egencache                    | 17 ++++++++++++++++-
 pym/portage/repository/config.py | 12 ++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/bin/egencache b/bin/egencache
index f97432f..6075ccf 100755
--- a/bin/egencache
+++ b/bin/egencache
@@ -1086,8 +1086,23 @@ def egencache_main(args):
 			ret.append(scheduler.returncode)
 
 	if options.update_pkg_desc_index:
+		if repo_config.writable:
+			writable_location = repo_config.location
+		else:
+			writable_location = os.path.join(portdb.depcachedir,
+				repo_config.location.lstrip(os.sep))
+			msg = [
+				"WARNING: Repository is not writable: %s" % (
+				repo_config.location,),
+				"         Using cache directory instead: %s" % (
+				writable_location,)
+			]
+			msg = "".join(line + '\n' for line in msg)
+			writemsg_level(msg,
+				level=logging.WARNING, noiselevel=-1)
+
 		gen_index = GenPkgDescIndex(portdb, os.path.join(
-			repo_config.location, "metadata", "pkg_desc_index"))
+			writable_location, "metadata", "pkg_desc_index"))
 		gen_index.run()
 		ret.append(gen_index.returncode)
 
diff --git a/pym/portage/repository/config.py b/pym/portage/repository/config.py
index e44b619..05eedbe 100644
--- a/pym/portage/repository/config.py
+++ b/pym/portage/repository/config.py
@@ -26,6 +26,7 @@ from portage.env.loaders import KeyValuePairFileLoader
 from portage.util import (normalize_path, read_corresponding_eapi_file, shlex_split,
 	stack_lists, writemsg, writemsg_level, _recursive_file_list)
 from portage.util._path import exists_raise_eaccess, isdir_raise_eaccess
+from portage.util.path import first_existing
 from portage.localization import _
 from portage import _unicode_decode
 from portage import _unicode_encode
@@ -346,6 +347,17 @@ class RepoConfig(object):
 		if new_repo.name is not None:
 			self.missing_repo_name = new_repo.missing_repo_name
 
+	@property
+	def writable(self):
+		"""
+		Check if self.location is writable, or permissions are sufficient
+		to create it if it does not exist yet.
+		@rtype: bool
+		@return: True if self.location is writable or can be created,
+			False otherwise
+		"""
+		return os.access(first_existing(self.location), os.W_OK)
+
 	@staticmethod
 	def _read_valid_repo_name(repo_path):
 		name, missing = RepoConfig._read_repo_name(repo_path)
-- 
2.3.5