Update following referenced licenses and rules

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_10.RULE

@@ -0,0 +1,6 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_tag: yes
+---
+
+license: LGPL/MPL

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_11.RULE

@@ -0,0 +1,6 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_notice: yes
+---
+
+dual-licensed under the LGPL and the MPL.

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_12.RULE

@@ -0,0 +1,9 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_notice: yes
+---
+
+Cairo is free software and is available to be redistributed and/or
+modified under the terms of either the GNU Lesser General Public
+License (LGPL) version 2.1 or the Mozilla Public License (MPL) version
+1.1.

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_13.RULE

@@ -0,0 +1,25 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_notice: yes
+referenced_filenames:
+    - COPYING-LGPL-2.1
+    - COPYING-MPL-1.1
+---
+
+is free software.
+
+Every source file in the implementation of is available to be
+redistributed and/or modified under the terms of either the GNU Lesser
+General Public License (LGPL) version 2.1 or the Mozilla Public
+License (MPL) version 1.1.  Some files are available under more
+liberal terms, but we believe that in all cases, each file may be used
+under either the LGPL or the MPL.
+
+See the following files in this directory for the precise terms and
+conditions of either license:
+
+	COPYING-LGPL-2.1
+	COPYING-MPL-1.1
+
+Please see each file in the implementation for copyright and licensing
+information, (in the opening comment of each file).

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_14.RULE

@@ -0,0 +1,10 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_reference: yes
+referenced_filenames:
+    - COPYING
+---
+
+* The code in the patch is copyright under the LGPL, but
+ * has been relicensed under the LGPL/MPL dual license for inclusion
+ * into (see COPYING).

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_7.RULE

@@ -0,0 +1,11 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_notice: yes
+referenced_filenames:
+    - COPYING
+---
+
+Cairo is released under the terms of either the {{GNU Lesser General Public
+License version 2.1}}, or the terms of the {{Mozilla Public License version 1.1}}.
+
+See the [`COPYING`](./COPYING) document for more information.

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_8.RULE

@@ -0,0 +1,7 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_notice: yes
+---
+
+Cairo is released under the terms of either the {{GNU Lesser General Public
+License version 2.1}}, or the terms of the {{Mozilla Public License version 1.1}}

src/licensedcode/data/rules/lgpl-2.1_or_mpl-1.1_9.RULE

@@ -0,0 +1,11 @@
+---
+license_expression: lgpl-2.1 OR mpl-1.1
+is_license_reference: yes
+---
+
+New license: LGPL/MPL
+
+The most significant news with this release is that the license of
+cairo has changed. It is now dual-licensed under the LGPL and the
+MPL. For details see the COPYING file as well as COPYING-LGPL-2.1 and
+COPYING-MPL-1.1.

src/licensedcode/detection.py

@@ -60,19 +60,19 @@ def logger_debug(*args):
 
 logger = logging.getLogger(__name__)
 
-if TRACE:
+if (
+    TRACE
+    or TRACE_ANALYSIS
+    or TRACE_REFERENCE
+    or TRACE_IS_FUNCTIONS
+):
 
-    if (
-        TRACE
-        or TRACE_ANALYSIS
-        or TRACE_IS_FUNCTIONS
-    ):
+    logging.basicConfig(stream=sys.stdout)
+    logger.setLevel(logging.DEBUG)
 
-        logging.basicConfig(stream=sys.stdout)
-        logger.setLevel(logging.DEBUG)
+    def logger_debug(*args):
+        return logger.debug(' '.join(isinstance(a, str) and a or repr(a) for a in args))
 
-        def logger_debug(*args):
-            return logger.debug(' '.join(isinstance(a, str) and a or repr(a) for a in args))
 
 MATCHER_UNDETECTED = '5-undetected'
 MATCHER_UNDETECTED_ORDER = 4
@@ -1455,6 +1455,12 @@ def use_referenced_license_expression(referenced_license_expression, license_det
     if same_license_keys and not same_expression:
         return False
 
+    # If all the license keys of the referenced license expression already
+    # present in the actual license expression
+    # note that this preserves AND/OR expressions in the original license
+    if referenced_license_keys.issubset(license_keys):
+        return False
+
     # when there are many license keys in an expression, and there are no
     # unknown or other cases, we cannot safely conclude that we should
     # follow the license in the referenced filenames. This is likely
@@ -2072,6 +2078,10 @@ def update_detection_from_referenced_files(
         relation='AND',
         licensing=get_cache().licensing,
     ))
+    if TRACE_REFERENCE:
+        logger_debug(
+            f'update_detection_from_referenced_files: referenced_license_expression: {referenced_license_expression}',
+        )
 
     if not use_referenced_license_expression(
         referenced_license_expression=referenced_license_expression,
@@ -2080,24 +2090,26 @@ def update_detection_from_referenced_files(
         if TRACE_REFERENCE and referenced_resources:
             paths = [
                 resource.path
-                for resource in referenced_resource
+                for resource in referenced_resources
             ]
             logger_debug(
                 f'use_referenced_license_expression: False for '
                 f'resources: {paths} and '
-                f'license_expression: {referenced_license_expression}',
+                f'referenced_license_expression: {referenced_license_expression}',
+                f'license_detection.expression: {license_detection.license_expression}',
             )
         return False
 
     if TRACE_REFERENCE and referenced_resources:
         paths = [
             resource.path
-            for resource in referenced_resource
+            for resource in referenced_resources
         ]
         logger_debug(
             f'use_referenced_license_expression: True for '
             f'resources: {paths} and '
-            f'license_expression: {referenced_license_expression}',
+            f'referenced_license_expression: {referenced_license_expression}',
+            f'license_detection.expression: {license_detection.license_expression}',
         )
 
     matches_to_extend = get_matches_from_detection_mappings(

src/licensedcode/plugin_license.py

@@ -210,15 +210,15 @@ def process_codebase(self, codebase, license_text=False, license_diagnostics=Fal
         modified = False
         for resource in codebase.walk(topdown=False):
             # follow license references to other files
-            if TRACE:
+            if TRACE_REFERENCE:
                 license_expressions_before = resource.detected_license_expression
 
             try:
                 modified = add_referenced_filenames_license_matches_for_detections(resource, codebase)
             except Exception as e:
                 raise Exception(f"Failed to process resource: {resource!r}") from e
 
-            if TRACE and modified:
+            if TRACE_REFERENCE and modified:
                 license_expressions_after = resource.detected_license_expression
                 logger_debug(
                     f'add_referenced_filenames_license_matches: Modified:',
@@ -291,6 +291,11 @@ def add_referenced_filenames_license_matches_for_detections(resource, codebase):
                 )
             continue
 
+        if TRACE_REFERENCE:
+            logger_debug(
+                f'add_referenced_license_matches: referenced_filenames: {referenced_filenames}',
+            )
+
         is_modified = update_detection_from_referenced_files(
             referenced_filenames=referenced_filenames,
             license_detection_mapping=license_detection_mapping,