eclean-pkg: add --unreachable to enable all --changed-* options

The set of reasons a binary package can no longer be a Portage cache hit
keeps growing (--changed-deps, --changed-subslot, --changed-iuse), and
users generally just want all of them cleaned. Add --unreachable as a
convenience that enables every --changed-* option at once, so new
reasons are picked up automatically without users having to learn each
flag.

Closes: https://bugs.gentoo.org/977235
Signed-off-by: Matt Turner <mattst88@gentoo.org>

Author: mattst88

man/eclean.1

@@ -119,6 +119,10 @@ This is only useful when scripting to ignore an otherwise fatal error.
 \fB\-\-changed\-iuse\fP		delete packages whose IUSE no longer matches the ebuild
 This is useful when, for instance, PYTHON_COMPAT changes and adds a new
 python_targets_* flag: the old binary package can never be a cache hit again.
+.TP
+\fB\-\-unreachable\fP		delete packages that can no longer be a Portage cache hit
+This enables all of the \-\-changed\-* options at once, so any binary package
+that Portage can no longer reuse is removed regardless of why.
 .SH "EXCLUSION FILES"
 Exclusions files are lists of packages names or categories you want to protect
 in particular.  This may be useful to protect more binary packages for some system

pym/gentoolkit/eclean/cli.py

@@ -271,6 +271,12 @@ def printUsage(_error=None, help=None, unresolved_invalids=None):
             + "               - delete packages whose IUSE no longer matches the ebuild",
             file=out,
         )
+        print(
+            yellow("     --unreachable")
+            + "                - delete packages that can no longer be a cache hit"
+            + " (enables all --changed-* options)",
+            file=out,
+        )
         print(
             yellow("     --no-clean-invalid")
             + "           - Skip cleaning invalid binpkgs",
@@ -432,6 +438,10 @@ def optionSwitch(option, opts, action=None):
                 options["changed-subslot"] = True
             elif o in ("--changed-iuse"):
                 options["changed-iuse"] = True
+            elif o in ("--unreachable"):
+                options["changed-deps"] = True
+                options["changed-subslot"] = True
+                options["changed-iuse"] = True
             elif o in ("-i", "--ignore-failure"):
                 options["ignore-failure"] = True
             elif o in ("-u", "--unique-use"):
@@ -488,6 +498,7 @@ def optionSwitch(option, opts, action=None):
         "changed-deps",
         "changed-subslot",
         "changed-iuse",
+        "unreachable",
         "unique-use",
         "no-clean-invalid",
     ]