[update]: `pdd update` fails to generate prompt file if prompt file does not exist.

[Isrothy]

Reproduction

mkdir pdd-issue
cd pdd-issue
echo "print('hello world')" >> hello.py
pdd --core-dump update --output hello_python.prompt hello.py 

Expected Behavior

Generate a prompt file hello_python.prompt

Error Message

Invalid path provided for modified_code_file: 'None' - argument should be a str or an os.PathLike object where __fspath__ returns a str, not 'NoneType'
Error: argument should be a str or an os.PathLike object where __fspath__ returns a str, not 'NoneType'
Error during 'update' command:
  An unexpected error occurred: cannot unpack non-iterable NoneType object
Debug: collect_files called
Debug: args = (<click.core.Context object at 0x10fbffed0>,)
Debug: kwargs keys = ['output', 'input_prompt_file', 'modified_code_file', 'input_code_file', 'use_git', 'extensions']
Debug: kwargs = {'output': 'hello_python.prompt', 'input_prompt_file': 'hello.py', 'modified_code_file': None, 'input_code_file': None, 'use_git': False, 'extensions': None}
Debug: Collected input files: ['hello.py']
Debug: Collected output files: ['hello_python.prompt']
Debug: Added to core_dump_files: /Users/jiangjoshua/tmp/pdd-issue/hello.py (exists: True)
Debug: Added to core_dump_files: /Users/jiangjoshua/tmp/pdd-issue/hello_python.prompt (exists: False)
Debug: Total files in core_dump_files: 2

--- Command Execution Summary ---
Error during 'unknown' command:
  An unexpected error occurred: 'NoneType' object is not iterable
Core dump: Found 2 tracked files
Core dump: Checking file /Users/jiangjoshua/tmp/pdd-issue/hello.py
Core dump: Added content for hello.py
Core dump: Checking file /Users/jiangjoshua/tmp/pdd-issue/hello_python.prompt
Core dump: File not found or not a file: /Users/jiangjoshua/tmp/pdd-issue/hello_python.prompt
Core dump written to /Users/jiangjoshua/tmp/pdd-issue/.pdd/core_dumps/pdd-core-20251213T200118Z.json. You can attach this file when reporting a bug.

Core dumped:

{
  "schema_version": 1,
  "pdd_version": "0.0.82",
  "timestamp_utc": "20251213T200118Z",
  "argv": [
    "--core-dump",
    "update",
    "--output",
    "hello_python.prompt",
    "hello.py"
  ],
  "cwd": "/Users/jiangjoshua/tmp/pdd-issue",
  "platform": {
    "system": "Darwin",
    "release": "25.1.0",
    "version": "Darwin Kernel Version 25.1.0: Mon Oct 20 19:34:05 PDT 2025; root:xnu-12377.41.6~2/RELEASE_ARM64_T6041",
    "python": "3.13.11 (main, Dec  5 2025, 16:06:33) [Clang 17.0.0 (clang-1700.4.4.1)]"
  },
  "global_options": {
    "force": false,
    "strength": 0.75,
    "temperature": 0.0,
    "time": 0.25,
    "verbose": false,
    "quiet": false,
    "local": false,
    "context": null,
    "output_cost": null,
    "review_examples": false
  },
  "invoked_subcommands": [
    "update"
  ],
  "total_cost": 0.0,
  "steps": [],
  "errors": [
    {
      "command": "update",
      "type": "TypeError",
      "message": "cannot unpack non-iterable NoneType object",
      "traceback": "Traceback (most recent call last):\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/pdd/commands/modify.py\", line 177, in update\n    result, total_cost, model_name = update_main(\n    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\nTypeError: cannot unpack non-iterable NoneType object\n"
    },
    {
      "command": "unknown",
      "type": "TypeError",
      "message": "'NoneType' object is not iterable",
      "traceback": "Traceback (most recent call last):\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/pdd/core/cli.py\", line 89, in invoke\n    result = super().invoke(ctx)\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/click/core.py\", line 1688, in invoke\n    return _process_result(sub_ctx.command.invoke(sub_ctx))\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/click/core.py\", line 1657, in _process_result\n    value = ctx.invoke(self._result_callback, value, **ctx.params)\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/click/core.py\", line 783, in invoke\n    return __callback(*args, **kwargs)\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/click/decorators.py\", line 33, in new_func\n    return f(get_current_context(), *args, **kwargs)\n  File \"/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/pdd/core/cli.py\", line 453, in process_commands\n    if num_results < num_commands and not all(res is None for res in results): # Avoid printing if all failed\n                                                                     ^^^^^^^\nTypeError: 'NoneType' object is not iterable\n"
    }
  ],
  "environment": {
    "PATH": "/opt/homebrew/Cellar/pyenv/2.6.16/libexec:/opt/homebrew/Cellar/pyenv/2.6.16/plugins/python-build/bin:/Users/jiangjoshua/.pyenv/shims:/Applications/Docker.app/Contents/Resources/cli-plugins/:/Applications/Docker.app/Contents/Resources/bin:/Users/jiangjoshua/.local/bin:/Users/jiangjoshua/.rustup/toolchains/nightly-aarch64-apple-darwin/bin:/opt/homebrew/opt/zip/bin:/opt/homebrew/opt/tcl-tk@8/bin:/opt/homebrew/opt/ruby/bin:/opt/homebrew/opt/postgresql@16/bin:/opt/homebrew/opt/openjdk/bin:/opt/homebrew/opt/llvm/bin:/opt/homebrew/opt/curl/bin:/opt/homebrew/bin:/opt/homebrew/opt/openjdk@21/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/opt/pmk/env/global/bin:/Library/Apple/usr/bin:/usr/local/share/dotnet:~/.dotnet/tools:/Users/jiangjoshua/.cargo/bin:/Applications/kitty.app/Contents/MacOS:/Users/jiangjoshua/Library/Application Support/Coursier/bin:/Users/jiangjoshua/Library/Application Support/JetBrains/Toolbox/scripts:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/lib:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/aliases:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/cabal:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/colored-man-pages:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/colorize:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/command-not-found:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/copybuffer:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/copyfile:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/copypath:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/dirhistory:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/fzf:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/git:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/gitignore:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/history-substring-search:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/jsontools:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/macos:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/stack:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/sudo:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/web-search:/Users/jiangjoshua/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/zoxide:/Users/jiangjoshua/.antigen/bundles/hlissner/zsh-autopair:/Users/jiangjoshua/.antigen/bundles/Aloxaf/fzf-tab:/Users/jiangjoshua/.antigen/bundles/zsh-users/zsh-completions:/Users/jiangjoshua/.antigen/bundles/zsh-users/zsh-syntax-highlighting:/Users/jiangjoshua/.antigen/bundles/zsh-users/zsh-autosuggestions:/Users/jiangjoshua/.antigen/bundles/jeffreytse/zsh-vi-mode:/Users/jiangjoshua/.lmstudio/bin:/Users/jiangjoshua/.cabal/bin:/Users/jiangjoshua/.ghcup/bin",
    "PDD_PATH": "/Users/jiangjoshua/Library/Application Support/pipx/venvs/pdd-cli/lib/python3.13/site-packages/pdd"
  },
  "file_contents": {
    "hello.py": "print('hello world')\n"
  },
  "terminal_output": "=== STDOUT ===\nChecking for updates...\nInvalid path provided for modified_code_file: 'None' - argument should be a str or an os.PathLike object where __fspath__ returns a str, not 'NoneType'\nError: argument should be a str or an os.PathLike object where __fspath__ returns a str, not 'NoneType'\nError during 'update' command:\n  An unexpected error occurred: cannot unpack non-iterable NoneType object\nDebug: collect_files called\nDebug: args = (<click.core.Context object at 0x10fbffed0>,)\nDebug: kwargs keys = ['output', 'input_prompt_file', 'modified_code_file', 'input_code_file', 'use_git', 'extensions']\nDebug: kwargs = {'output': 'hello_python.prompt', 'input_prompt_file': 'hello.py', 'modified_code_file': None, 'input_code_file': None, 'use_git': False, 'extensions': None}\nDebug: Collected input files: ['hello.py']\nDebug: Collected output files: ['hello_python.prompt']\nDebug: Added to core_dump_files: /Users/jiangjoshua/tmp/pdd-issue/hello.py (exists: True)\nDebug: Added to core_dump_files: /Users/jiangjoshua/tmp/pdd-issue/hello_python.prompt (exists: False)\nDebug: Total files in core_dump_files: 2\n\n--- Command Execution Summary ---\nError during 'unknown' command:\n  An unexpected error occurred: 'NoneType' object is not iterable\n"
}

[Isrothy]

@jiaminc-cmu would you mind checking out this issue?

[jiaminc-cmu]

@jiaminc-cmu would you mind checking out this issue?

ok