Add UNINSTALL_IGNORE variable for bug #421659.

UNINSTALL_IGNORE = [space delimited list of fnmatch patterns]

This variable prevents uninstallation of files that match
specific fnmatch(3) patterns. In order to ignore file collisions
with these files at install time, the same patterns can be
added to the COLLISION_IGNORE variable.

4 files changed, 25 insertions, 14 deletions

diff --git a/cnf/make.globals b/cnf/make.globals
index b1569885b..c35429143 100644
--- a/cnf/make.globals
+++ b/cnf/make.globals
@@ -64,6 +64,7 @@ FEATURES="assume-digests binpkg-logs
 # transition from compiling python modules in live file system to compiling
 # them in src_install() function.
 COLLISION_IGNORE="/lib/modules/* *.py[co]"
+UNINSTALL_IGNORE="/lib/modules/*"
 
 # Enable preserve-libs for testing with portage versions that support it.
 # This setting is commented out for portage versions that don't support it.
diff --git a/man/make.conf.5 b/man/make.conf.5
index 688263709..7d07344bd 100644
--- a/man/make.conf.5
+++ b/man/make.conf.5
@@ -896,6 +896,14 @@ is used to sync the local portage tree when `emerge \-\-sync` is run.
 .br
 Defaults to rsync://rsync.gentoo.org/gentoo\-portage
 .TP
+\fBUNINSTALL_IGNORE\fR = \fI[space delimited list of fnmatch patterns]\fR
+This variable prevents uninstallation of files that match
+specific \fBfnmatch\fR(3) patterns. In order to ignore file
+collisions with these files at install time, the same patterns
+can be added to the \fBCOLLISION_IGNORE\fR variable.
+.br
+Defaults to "/lib/modules/*".
+.TP
 \fBUSE\fR = \fI[space delimited list of USE items]\fR
 This variable contains options that control the build behavior of several
 packages.  More information in \fBebuild\fR(5).  Possible USE values
diff --git a/pym/portage/dbapi/vartree.py b/pym/portage/dbapi/vartree.py
index b8405d483..60bab73ba 100644
--- a/pym/portage/dbapi/vartree.py
+++ b/pym/portage/dbapi/vartree.py
@@ -2064,7 +2064,9 @@ class dblink(object):
 
 			#process symlinks second-to-last, directories last.
 			mydirs = set()
-			modprotect = os.path.join(self._eroot, "lib/modules/")
+
+			uninstall_ignore = portage.util.shlex_split(
+				self.settings.get("UNINSTALL_IGNORE", ""))
 
 			def unlink(file_name, lstatobj):
 				if bsd_chflags:
@@ -2171,6 +2173,18 @@ class dblink(object):
 				if lstatobj is None:
 						show_unmerge("---", unmerge_desc["!found"], file_type, obj)
 						continue
+
+				f_match = obj[len(eroot)-1:]
+				ignore = False
+				for pattern in uninstall_ignore:
+					if fnmatch.fnmatch(f_match, pattern):
+						ignore = True
+						break
+
+				if ignore:
+					show_unmerge("---", unmerge_desc["cfgpro"], file_type, obj)
+					continue
+
 				# don't use EROOT, CONTENTS entries already contain EPREFIX
 				if obj.startswith(real_root):
 					relative_path = obj[real_root_len:]
@@ -2214,18 +2228,6 @@ class dblink(object):
 						continue
 					elif relative_path in cfgfiledict:
 						stale_confmem.append(relative_path)
-				# next line includes a tweak to protect modules from being unmerged,
-				# but we don't protect modules from being overwritten if they are
-				# upgraded. We effectively only want one half of the config protection
-				# functionality for /lib/modules. For portage-ng both capabilities
-				# should be able to be independently specified.
-				# TODO: For rebuilds, re-parent previous modules to the new
-				# installed instance (so they are not orphans). For normal
-				# uninstall (not rebuild/reinstall), remove the modules along
-				# with all other files (leave no orphans).
-				if obj.startswith(modprotect):
-					show_unmerge("---", unmerge_desc["cfgpro"], file_type, obj)
-					continue
 
 				# Don't unlink symlinks to directories here since that can
 				# remove /lib and /usr/lib symlinks.
diff --git a/pym/portage/package/ebuild/_config/special_env_vars.py b/pym/portage/package/ebuild/_config/special_env_vars.py
index 4795e88bc..a01c17714 100644
--- a/pym/portage/package/ebuild/_config/special_env_vars.py
+++ b/pym/portage/package/ebuild/_config/special_env_vars.py
@@ -164,7 +164,7 @@ environ_filter += [
 	"RESUMECOMMAND", "RESUMECOMMAND_FTP",
 	"RESUMECOMMAND_HTTP", "RESUMECOMMAND_HTTPS",
 	"RESUMECOMMAND_RSYNC", "RESUMECOMMAND_SFTP",
-	"SYNC", "USE_EXPAND_HIDDEN", "USE_ORDER",
+	"SYNC", "UNINSTALL_IGNORE", "USE_EXPAND_HIDDEN", "USE_ORDER",
 ]
 
 environ_filter = frozenset(environ_filter)