Fix module resolution for subdirectory paths (top and required modules)

[pedjaradenkovic]

Problem

Two related failures when a .plain module lives in / references a subdirectory:

1. Running the CLI with a relative path containing a subdirectory fails:

   $ python plain2code.py examples/example_hello_world_python/hello_world_python.plain
   Error: Module does not exist (examples/example_hello_world_python/hello_world_python).
   

2. A top module that requires a module in a subdirectory (requires: [dir_name/b]), rendered from outside its folder, fails when the PlainModule tree is built:

   Error: Module does not exist (b).
   

Root cause

get_template_directories always folds dirname(filename) into template_dirs[0]. But the full top-module filename was still passed to plain_file_parser, so the directory was counted twice when opening the file (open_from joins template_dirs[0] + the module name).

• Required/imported modules are already passed as template-relative names (dir_name/b.plain), so they must keep their subdirectory prefix to resolve.
• The top module must drop its directory prefix (it's already in template_dirs).

An earlier attempt fixed only the top module by forcing the bare stem — but that stripped the subdirectory from required modules too, breaking case 2.

Fix

• plain2code.py: normalize the top module to os.path.basename(args.filename) at the call sites (its directory is already in template_dirs). This is the frame the parser expects.
• plain_file.py: plain_file_parser preserves the relative subdirectory prefix in module_name (so dir_name/b resolves and is retained in build/conformance paths); absolute paths fall back to the stem.

With this, both the top module and required modules in subdirectories resolve correctly, and required-module subdirectory structure is preserved under the build folder (build/dir_name/b).

Tests

tests/test_plainfileparser.py (fixtures in tests/data/requires_subdir/):

• test_parser_keeps_subdirectory_in_module_name — parser keeps nested/leaf for a template-relative name.
• test_requires_module_in_subdirectory_resolves — builds the full PlainModule tree with a required subdirectory module (the path that broke) and asserts module names + build folder (build/nested/leaf).

Verification

• Full suite: 217 passed; black / flake8 / mypy clean.
• Original relative-subfolder CLI invocation works.
• requires: [dir_name/b] from outside the folder now builds the module tree and reaches the API instead of failing at "Module does not exist".

[NejcS]

I don't think this is needed anymore since PR #168 was merged. I tested on the latest main branch (after #168 was merged) and I can run the rendering the way that is described in the two above failures.

Case 1:

(.venv) ➜  codeplain git:(main) pwd
/Users/nejcstebe/codeplain/codeplain
(.venv) ➜  codeplain git:(main) python plain2code.py examples/example_hello_world_python/hello_world_python.plain --full-plain
Full plain text:

---
description: '"hello, world" in Plain (Python version)'
import:
  - python-console-app-template
---

***implementation reqs***

- :MainExecutableFile: of :App: should be called "hello_world.py".

***functional specs***

- Display "hello, world"

  ***acceptance tests***

  - :App: should exit with status code 0 indicating successful execution.

  - :App: should complete execution in under 1 second.

Case 2, I modified the password manager example so that vault-cli.plain requires temp_dir/password_manager.plain.

(.venv) ➜  codeplain git:(main) ✗ pwd
/Users/nejcstebe/codeplain/codeplain
(.venv) ➜  codeplain git:(main) ✗ python plain2code.py ../cli-password-manager/vault-cli.plain --full-plain
Full plain text:

---
import:
  - vault_reqs
  - entry_reqs
requires:
  - test_dir/password_manager
---

***implementation reqs***

- The commands should be implemented in the :CLI:.

- :CLI: is defined in the vault.py

- The functions from :PasswordManagerModule: should be used for password inputs.

- All :CLI: functions operating on :Vault: should accept optional --path argument that explicitly defines :Vault: storage file path.

***test reqs***

- Some functionalities require user input to work. The conformance tests should simulate or mock the input functions to test these functionalities.

***functional specs***

- Implement the Help command which prints out the usage for the :Vault: app
  - This Help command should be called if :CLI: is run without input arguments or help command argument.

- Implement an Initialization Command (`init`)
  - Ask the user for the password
  - Get the :EncryptionKey: and KDF parameters using the get_key function in the key_management module.
  - The function should initialize the :Vault: using the :EncryptionKey: and KDF parameters.

- Implement an Add Command (`add`) that adds an additional password to the :Vault:
  - Ask the user for entry details
  - The function should call the add_entry function of the vault_functions module.

- Implement the Get Command (`get`) which retrieves the :Entry: password
  - Takes an :Entry: ID and the :Vault: storage file path as input.
  - The function should call the get_entry function of the vault_functions module.

- Implement the Delete Command (`delete`)
  - Takes an :Entry: ID and the :Vault: storage file path as input.
  - The function should call the delete_entry function of the vault_functions module.

- Implement the List Command (`list`)
  - Takes the :Vault: storage file path as input.
  - The function should call the list_entries function of the vault_functions module.