Update tornado's lower bound to the earliest secure version

[ulgens]

The latest release of the 5.x series was in 2018 and has never received a security update since then. The latest found security issue of the 6.x series is fixed in 6.5.0

Resolves:

• Security Suggestion: Please upgrade Tornado to 6.4.2 to fix CVE-2024-7592 #1439

Depends on:

• Remove Python 3.8 support (EOL) #1463

I'll rebase the branch when #1463 is merged.

[ulgens]

@Nusnus 👋🏻

[Copilot]

Pull Request Overview

This PR modernizes the codebase by dropping support for older Python versions (3.7 and 3.8), bumping the minimum Tornado version to 6.5.0, and applying various code style improvements including converting %-formatting to f-strings/.format(), using raw strings for regex patterns, and simplifying comprehensions.

Key Changes

• Bumps minimum Tornado version from 5.0.0 to 6.5.0 and removes testing for Tornado versions 6.0-6.4
• Removes Python 3.7 and 3.8 from setup.py classifiers and CI matrix
• Modernizes code style: f-strings, dict/set literals, raw strings, and exception handling

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tox.ini	Reduces tornado version test matrix to only 6.5
setup.py	Removes Python 3.7 and 3.8 version classifiers
requirements/default.txt	Bumps minimum tornado version to 6.5.0
.github/workflows/build.yml	Updates CI to test Python 3.9-3.12 with Tornado 6.5
tests/unit/views/test_auth.py	Uses raw string literal for regex pattern
tests/unit/test_command.py	Modernizes to use byte literals and f-strings
flower/views/workers.py	Simplifies dict comprehension syntax
flower/views/init.py	Uses set literals instead of set([])
flower/utils/search.py	Attempts to convert list comprehension to generator (contains bug)
flower/utils/broker.py	Replaces deprecated socket.error and IOError with OSError
flower/utils/init.py	Converts %-formatting to .format()
flower/command.py	Replaces deprecated IOError with OSError
examples/tasks.py	Converts %-formatting to f-string
docs/conf.py	Removes Python 2 encoding declaration

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[Copilot]

The tox.ini still includes Python 3.8 in the test matrix (py38), but setup.py removed the Python 3.8 classifier. This creates an inconsistency - if Python 3.8 support is being dropped, it should also be removed from the tox test matrix. If Python 3.8 is still supported, the classifier should remain in setup.py.

[Copilot]

The CI matrix removes Python 3.8 but setup.py classifiers also remove it while tox.ini still includes py38. For consistency, if Python 3.8 support is being dropped completely, it should be removed from tox.ini as well, or if it's being kept, it should remain in setup.py classifiers and the CI matrix.

Suggested change

	python-version: ['3.9', '3.10', '3.11', '3.12']
	python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']

[Copilot]

This change from a list comprehension to a generator expression will break the unpacking operation. Python cannot unpack a generator directly with tuple unpacking syntax. The original [p.strip() for p in ...] returns a list that can be unpacked, but (p.strip() for p in ...) returns a generator object that cannot be unpacked this way.

To fix this while still using a generator-like approach, you should use: key, value = query_part[len('kwargs:'):].split('=') and then apply .strip() to each variable individually, or keep the list comprehension.

Suggested change

	key, value = (p.strip() for p in query_part[len('kwargs:'):].split('='))
	key, value = [p.strip() for p in query_part[len('kwargs:'):].split('=')]

[Copilot]

The python_requires field in setup.py still specifies ">=3.7", but the PR removes Python 3.7 and 3.8 from the classifiers and the tox.ini still tests Python 3.8. This creates an inconsistency - either python_requires should be updated to ">=3.8" (if Python 3.8 is the new minimum as tested in tox.ini) or ">=3.9" (if dropping 3.8 support as indicated by the removed classifiers).

[ulgens]

@auvipy This PR needs some time before the review. If possible, can you please check #1462 first?