encapsulate sys.stdout.flush() into logger, guard against None sys.stdout (ESPTOOL-1008)

[brentpicasso]

This change fixes the following bug(s):

fix(esptool/all) : Encapsulates sys.stdout.flush() in logger, with a guard if stdout is not valid (e.g. None)

Resolves #1063

We are using esptool to flash firmware in the context of our app.

This app runs on Kivy, and built with Pyinstaller. On windows, it appears that sys.stdout is not available (sys.stdout is None)

Under these conditions, esptool will crash when sys.stdout.flush() is called

What is the Expected Behaviour?

esptool should guard against this condition and not crash if sys.stdout is not available.

Encapsulates sys.stdout.flush() in logger, with a guard if stdout is not valid (e.g. None)

[github-actions]

Warnings

⚠️

Some issues found for the commit messages in this PR: the commit message "encapsulate flush in logger, guard against missing sys.stdout": summary looks empty type/action looks empty Please fix these commit messages - here are some basic tips: follow Conventional Commits style correct format of commit message should be: <type/action>(<scope/component>): <summary>, for example fix(esp32): Fixed startup timeout issue allowed types are: change,ci,docs,feat,fix,refactor,remove,revert,test sufficiently descriptive message summary should be between 20 to 72 characters and start with upper case letter avoid Jira references in commit messages (unavailable/irrelevant for our customers) TIP: Install pre-commit hooks and run this check when committing (uses the Conventional Precommit Linter).

👋 Hello brentpicasso, we appreciate your contribution to this project!

---

📘 Please review the project's Contributions Guide for key guidelines on code, documentation, testing, and more.

---

Click to see more instructions ...

This automated output is generated by the PR linter DangerJS, which checks if your Pull Request meets the project's requirements and helps you fix potential issues.

DangerJS is triggered with each push event to a Pull Request and modify the contents of this comment.

Please consider the following:
- Danger mainly focuses on the PR structure and formatting and can't understand the meaning behind your code or changes.
- Danger is not a substitute for human code reviews; it's still important to request a code review from your colleagues.
- Resolve all warnings (⚠️ ) before requesting a review from human reviewers - they will appreciate it.
- To manually retry these Danger checks, please navigate to the Actions tab and re-run last Danger workflow.

Review and merge process you can expect ...

We do welcome contributions in the form of bug reports, feature requests and pull requests via this public GitHub repository.

This GitHub project is public mirror of our internal git repository

1. An internal issue has been created for the PR, we assign it to the relevant engineer.
2. They review the PR and either approve it or ask you for changes or clarifications.
3. Once the GitHub PR is approved, we synchronize it into our internal git repository.
4. In the internal git repository we do the final review, collect approvals from core owners and make sure all the automated tests are passing.
- At this point we may do some adjustments to the proposed change, or extend it by adding tests or documentation.
5. If the change is approved and passes the tests it is merged into the default branch.
5. On next sync from the internal git repository merged change will appear in this public GitHub repository.

Generated by 🚫 dangerJS against a241c4c

[radimkarnis]

Hi @brentpicasso,
thanks for the report and the PR!

The usage of sys.stdout.flush() seems like a remnant from the days of Python 2 support. In Python 3, the default string ending when print is called is "\n", which triggers a flush. In other cases (when end="" is specified), print() can be called with the flush=True argument to force a flush.

That means we can get rid of some of these calls in esptool completely (e.g. every sys.stdout.flush() after print_overwrite(), because it calls print(flush=True)). And in other cases, we can just add the flush=True argument to the previous print statements. This way, we don't have to extend the logger class with a new method and proper flushing will be handled automatically.

Would you want to look into this, or do you want me to take over? It would be great if you could at least verify this works in your scenario. Thanks a lot!

[brentpicasso]

Hi radimkarnis - thanks for looking into it! I agree, making it even more simple would be best, so long at we don't try to access stdout is None.

Yes, please take on finishing the issue, I think that would be best at this point.

[brentpicasso]

Thank you @radimkarnis for handling it!