Update CHANGELOG, docs and CLI option tests

Signed-off-by: Ayan Sinha Mahapatra <ayansmahapatra@gmail.com>

Author: AyanSinhaMahapatra

CHANGELOG.rst

@@ -37,6 +37,12 @@ v33.0.0 (next next, roadmap)
 v32.1.0 (next, roadmap)
 ----------------------------
 
+New CLI options:
+
+- A new CLI option ``--package-only`` has been added which performs
+  a faster package scan by skipping the package assembly step and
+  also skipping license/copyright detection on package metadata.
+
 Major API/other changes:
 
 - Output Format Version updated to 3.1.0 (minor version bump)

docs/source/rst_snippets/basic_options.rst

@@ -33,6 +33,10 @@ documenting a program's options. For example:
 --system-package             Scan ``<input>`` for installed system package
                              databases.
 
+--package-only               Scan ``<input>`` for system and application
+                             only for package metadata, without license/
+                             copyright detection and package assembly.
+
 -e, --email                  Scan ``<input>`` for emails.
 
                              Sub-Options:

src/packagedcode/plugin_package.py

@@ -166,9 +166,11 @@ class PackageScanner(ScanPlugin):
             ),
             is_flag=True,
             default=False,
+            conflicting_options=['license', 'summary', 'package', 'system_package'],
             help=(
-                'Only detect package information and skip license/copyright detection steps, '
-                'in application package and dependency manifests, lockfiles and related data.'
+                'Only detect package metadata and skip license/copyright detection steps, '
+                'and skip package assembly in package and dependency manifests, lockfiles '
+                'and related data.'
             ),
             help_group=SCAN_GROUP,
             sort_order=22,

tests/packagedcode/test_plugin_package.py

@@ -227,6 +227,42 @@ def test_package_list_command(self, regen=REGEN_TEST_FIXTURES):
                 ef.write(result.output)
         assert result.output == open(expected_file).read()
 
+    def test_plugin_package_only_fails_with_license_scan(self):
+        test_dir = self.get_test_loc('maven2')
+        result_file = self.get_temp_file('json')
+        try:
+            run_scan_click(['--package-only', '--license', test_dir, '--json', result_file])
+            raise Exception("This SCAN should raise an AssertionError for conflicting CLI options")
+        except AssertionError:
+            pass
+    
+    def test_plugin_package_only_fails_with_summary_scan(self):
+        test_dir = self.get_test_loc('maven2')
+        result_file = self.get_temp_file('json')
+        try:
+            run_scan_click(['--package-only', '--summary', '--classify', test_dir, '--json', result_file])
+            raise Exception("This SCAN should raise an AssertionError for conflicting CLI options")
+        except AssertionError:
+            pass
+
+    def test_plugin_package_only_fails_with_package_scan(self):
+        test_dir = self.get_test_loc('maven2')
+        result_file = self.get_temp_file('json')
+        try:
+            run_scan_click(['--package-only', '--package', test_dir, '--json', result_file])
+            raise Exception("This SCAN should raise an AssertionError for conflicting CLI options")
+        except AssertionError:
+            pass
+
+    def test_plugin_package_only_fails_with_system_package_scan(self):
+        test_dir = self.get_test_loc('maven2')
+        result_file = self.get_temp_file('json')
+        try:
+            run_scan_click(['--package-only', '--system-package', test_dir, '--json', result_file])
+            raise Exception("This SCAN should raise an AssertionError for conflicting CLI options")
+        except AssertionError:
+            pass
+
     def test_system_package_get_installed_packages(self):
         test_dir = self.extract_test_tar('debian/basic-rootfs.tar.gz')
         expected_file = self.get_test_loc('plugin/get_installed_packages-expected.json')