[matter] log and report packages not built due to missing USE flags

matter/matter/builder.py

@@ -81,6 +81,7 @@ class PackageBuilder(object):
         self._not_found_packages = []
         self._not_installed_packages = []
         self._not_merged_packages = []
+        self._missing_use_packages = {}
 
     @classmethod
     def _build_standard_environment(cls, repository=None):
@@ -159,6 +160,13 @@ class PackageBuilder(object):
         """
         return self._not_merged_packages
 
+    def get_missing_use_packages(self):
+        """
+        Return the list of packages that haven't been merged due to missing
+        USE flags.
+        """
+        return self._missing_use_packages
+
     def run(self):
         """
         Execute Package building action.
@@ -686,6 +694,28 @@ class PackageBuilder(object):
             # print issues to stdout and give up
             print_warning("dependencies calculation failed, aborting")
             graph.display_problems()
+
+            # try to collect some info about the failure
+            bt_config = (graph.get_backtrack_infos() or {}).get("config", {})
+            supported_info = ["needed_use_config_changes"]
+            for k, v in bt_config.items():
+                if k not in supported_info:
+                    print_warning("unsupported backtrack info: %s -> %s" % (
+                            k, v,))
+                    continue
+                if k == "needed_use_config_changes":
+                    for tup in v:
+                        try:
+                            pkg, (new_use, new_changes) = tup
+                        except (ValueError, TypeError):
+                            print_error(
+                                "unsupported needed_use_config_changes: %s" % (
+                                    tup,))
+                            continue
+                        obj = self._missing_use_packages.setdefault(pkg.cpv, {})
+                        obj["pkg"] = pkg
+                        obj["changes"] = new_changes
+
             return 0
         print_info("dependency graph generated successfully")
 

matter/matter/main.py

@@ -85,6 +85,7 @@ def matter_main(binary_pms, nsargs, cwd, specs):
     not_installed = []
     not_merged = []
     uninstalled = []
+    missing_use = {}
     tainted_repositories = set()
     spec_count = 0
     tot_spec = len(specs)
@@ -113,6 +114,8 @@ def matter_main(binary_pms, nsargs, cwd, specs):
                 builder.get_not_merged_packages())
             uninstalled.extend(
                 builder.get_uninstalled_packages())
+            missing_use.update(
+                builder.get_missing_use_packages())
             preserved_libs = binary_pms.check_preserved_libraries(
                 emerge_config)
 
@@ -188,6 +191,20 @@ def matter_main(binary_pms, nsargs, cwd, specs):
         "\n  ".join(sorted(not_installed)),))
     print_info("Packages uninstalled:\n  %s" % (
         "\n  ".join(sorted(uninstalled)),))
+
+    if missing_use:
+        print_info("Packages not built due to missing USE flags:")
+        for atom in sorted(missing_use.keys()):
+            use_data = missing_use[atom]
+            use_l = []
+            for use in sorted(use_data["changes"]):
+                if use_data["changes"][use]:
+                    use_l.append(use)
+                else:
+                    use_l.append("-" + use)
+            print_info("%s %s" % (
+                    use_data["pkg"].slot_atom, " ".join(use_l)))
+
     print_info("Preserved libs: %s" % (
         preserved_libs,))
     print_info("")