Added multi-level inheritance support for import.

Signed-off-by: Leander Stephen D'Souza <leanderdsouza1234@gmail.com>

Author: leander-dsouza

README.md

@@ -135,6 +135,64 @@ For instance, consider the following two files:
    ```
 The resulting extension import would import vcs2l at version `main`, `immutable/hash` at version `25e4ae2` and `immutable/tag` at version `1.1.5`.
 
+#### Multiple Extensions
+
+The `extends` key also supports a list of files to extend from. The files are imported in the order they are specified and the precedence is given to the last file in case of duplicate repository entries.
+
+For instance, consider the following three files:
+
+- **`base_1.repos`**: contains two repositories `vcs2l` and `immutable/hash`, checked out at `1.1.3`.
+
+   ```yaml
+   ---
+   repositories:
+    immutable/hash:
+      type: git
+      url: https://github.com/ros-infrastructure/vcs2l.git
+      version: e700793cb2b8d25ce83a611561bd167293fd66eb  # 1.1.3
+     vcs2l:
+       type: git
+       url: https://github.com/ros-infrastructure/vcs2l.git
+       version: 1.1.3
+    ```
+
+- **`base_2.repos`**: contains two repositories `vcs2l` and `immutable/hash`, checked out at `1.1.4`.
+
+   ```yaml
+   ---
+   repositories:
+    immutable/hash:
+      type: git
+      url: https://github.com/ros-infrastructure/vcs2l.git
+      version: 2c7ff89d12d8a77c36b60d1f7ba3039cdd3f742b  # 1.1.4
+     vcs2l:
+       type: git
+       url: https://github.com/ros-infrastructure/vcs2l.git
+       version: 1.1.4
+  ```
+
+- **`multiple_extension.repos`**: extends both base files and overrides the version of `vcs2l` repository.
+
+   ```yaml
+   ---
+   extends:
+     - base_1.repos  # Lower priority
+     - base_2.repos # Higher priority
+   repositories:
+     vcs2l:
+       type: git
+       url: https://github.com/ros-infrastructure/vcs2l.git
+       version: 1.1.5
+   ```
+
+The resulting extension import would import `immutable/hash` at version `1.1.4` (from `base_2.repos`) and `vcs2l` at version `1.1.5`.
+
+Duplicate file names in the `extends` list are not allowed and would raise the following error:
+
+```bash
+Duplicate entries found in extends in file: <relative-path>/multiple_extension.repos
+```
+
 #### Circular Loop Protection
 
 In order to avoid infinite loops in case of circular imports the tool detects already imported files and raises an error if such a file is encountered again.

test/import_multiple_extends.txt

@@ -0,0 +1,49 @@
+......
+=== ./immutable/hash (git) ===
+Cloning into '.'...
+Note: switching to '2c7ff89d12d8a77c36b60d1f7ba3039cdd3f742b'.
+
+You are in 'detached HEAD' state. You can look around, make experimental
+changes and commit them, and you can discard any commits you make in this
+state without impacting any branches by switching back to a branch.
+
+If you want to create a new branch to retain commits you create, you may
+do so (now or later) by using -c with the switch command. Example:
+
+  git switch -c <new-branch-name>
+
+Or undo this operation with:
+
+  git switch -
+
+Turn off this advice by setting config variable advice.detachedHead to false
+
+HEAD is now at 2c7ff89 1.1.4
+=== ./immutable/hash_tar (tar) ===
+Downloaded tarball from 'https://github.com/ros-infrastructure/vcs2l/archive/377d5b3d03c212f015cc832fdb368f4534d0d583.tar.gz' and unpacked it
+=== ./immutable/hash_zip (zip) ===
+Downloaded zipfile from 'https://github.com/ros-infrastructure/vcs2l/archive/377d5b3d03c212f015cc832fdb368f4534d0d583.zip' and unpacked it
+=== ./immutable/tag (git) ===
+Cloning into '.'...
+Note: switching to 'tags/1.1.5'.
+
+You are in 'detached HEAD' state. You can look around, make experimental
+changes and commit them, and you can discard any commits you make in this
+state without impacting any branches by switching back to a branch.
+
+If you want to create a new branch to retain commits you create, you may
+do so (now or later) by using -c with the switch command. Example:
+
+  git switch -c <new-branch-name>
+
+Or undo this operation with:
+
+  git switch -
+
+Turn off this advice by setting config variable advice.detachedHead to false
+
+HEAD is now at 25e4ae2 1.1.5
+=== ./vcs2l (git) ===
+Cloning into '.'...
+=== ./without_version (git) ===
+Cloning into '.'...

test/list_extension.repos

@@ -1,4 +1,4 @@
-# Check for hash, tag, and branch imports with extends functionality
+# Check for hash, tag, and branch imports with extends functionality with predominant tag 1.1.3
 ---
 extends: list.repos
 repositories:

test/list_extension_2.repos

@@ -0,0 +1,16 @@
+# Check for hash, tag, and branch imports with extends functionality with predominant tag 1.1.4
+---
+extends: list.repos
+repositories:
+  immutable/hash:
+    type: git
+    url: https://github.com/ros-infrastructure/vcs2l.git
+    version: 2c7ff89d12d8a77c36b60d1f7ba3039cdd3f742b  # 1.1.4
+  immutable/tag:
+    type: git
+    url: https://github.com/ros-infrastructure/vcs2l.git
+    version: tags/1.1.4
+  vcs2l:
+    type: git
+    url: https://github.com/ros-infrastructure/vcs2l.git
+    version: 1.1.4

test/list_multiple_extension.repos

@@ -0,0 +1,14 @@
+# Check for multiple levels of extension in repositories files.
+---
+extends:
+  - list_extension.repos  # predominant tag is 1.1.3   # Lower priority
+  - list_extension_2.repos # predominant tag is 1.1.4  # Higher priority
+repositories:
+  immutable/tag:
+    type: git
+    url: https://github.com/ros-infrastructure/vcs2l.git
+    version: tags/1.1.5
+  vcs2l:
+    type: git
+    url: https://github.com/ros-infrastructure/vcs2l.git
+    version: main

test/test_commands.py

@@ -15,6 +15,9 @@
 REPOS_FILE_URL = file_uri_scheme + REPOS_FILE
 REPOS2_FILE = os.path.join(os.path.dirname(__file__), 'list2.repos')
 REPOS_EXTENDS_FILE = os.path.join(os.path.dirname(__file__), 'list_extension.repos')
+REPOS_MULTIPLE_EXTENDS_FILE = os.path.join(
+    os.path.dirname(__file__), 'list_multiple_extension.repos'
+)
 REPOS_EXTENDS_LOOP_FILE = os.path.join(
     os.path.dirname(__file__), 'loop_extension.repos'
 )
@@ -351,6 +354,10 @@ def test_import_extends_loop(self):
             run_command('import', ['--input', REPOS_EXTENDS_LOOP_FILE, '.'])
         self.assertIn(b'Circular import detected:', e.exception.output)
 
+    def test_import_multiple_extends(self):
+        """Test import with multiple extends functionality."""
+        self.import_common('import_multiple_extends', REPOS_MULTIPLE_EXTENDS_FILE)
+
     def test_validate(self):
         output = run_command('validate', ['--input', REPOS_FILE])
         expected = get_expected_output('validate')

vcs2l/commands/import_.py

@@ -128,27 +128,37 @@ def get_repositories(yaml_file, visited_files=None):
         combined_repos = {}
 
         if 'extends' in root:
-            parent_file = root['extends']
-
-            # If absolute path is not valid, try relative to current file
-            if not os.path.isabs(parent_file):
-                current_dir = os.path.dirname(current_file_path)
-                parent_file = os.path.join(current_dir, parent_file)
-
-            if not os.path.exists(parent_file):
-                raise RuntimeError(f'Parent file not found: {parent_file}')
-
-            try:
-                # Recursively get repositories from parent file
-                with open(parent_file, 'r', encoding='utf-8') as parent_f:
-                    parent_repos = get_repositories(parent_f, visited_files.copy())
-                    combined_repos.update(parent_repos)
-            except Exception as e:
-                if str(e).startswith('Circular import detected:'):
-                    raise
+            parent_files = root['extends']
+            # Convert single file to list for consistent processing
+            if isinstance(parent_files, str):
+                parent_files = [parent_files]
+
+            # Check for duplicate entries in extends
+            if len(parent_files) != len(set(parent_files)):
                 raise RuntimeError(
-                    f'Error reading parent file {parent_file}: \n{str(e)}'
-                ) from e
+                    f'Duplicate entries found in extends in file: {current_file_path}'
+                )
+
+            for parent_file in parent_files:
+                # If absolute path is not valid, try relative to current file
+                if not os.path.isabs(parent_file):
+                    current_dir = os.path.dirname(current_file_path)
+                    parent_file = os.path.join(current_dir, parent_file)
+
+                if not os.path.exists(parent_file):
+                    raise RuntimeError(f'Parent file not found: {parent_file}')
+
+                try:
+                    # Recursively get repositories from parent file
+                    with open(parent_file, 'r', encoding='utf-8') as parent_f:
+                        parent_repos = get_repositories(parent_f, visited_files.copy())
+                        combined_repos.update(parent_repos)
+                except Exception as e:
+                    if str(e).startswith('Circular import detected:'):
+                        raise
+                    raise RuntimeError(
+                        f'Error reading parent file {parent_file}: \n{str(e)}'
+                    ) from e
 
         current_repos = get_repositories_from_root(root)
         combined_repos.update(current_repos)
@@ -158,9 +168,7 @@ def get_repositories(yaml_file, visited_files=None):
     except FileNotFoundError as e:
         raise RuntimeError(f'File not found: {yaml_file}') from e
     except yaml.YAMLError as e:
-        raise RuntimeError(
-            f'Error parsing YAML file {yaml_file}: {str(e)}'
-        ) from e
+        raise RuntimeError(f'Error parsing YAML file {yaml_file}: {str(e)}') from e
     finally:
         # Remove current file from visited set when leaving this call
         visited_files.discard(current_file_path)