gh-149189: Modern defaults for pprint

[hugovk]

Given:

from pprint import pprint

config = {
    "database": {
        "host": "db.example.com",
        "port": 5432,
        "options": {
            "connect_timeout": 5,
            "pool_size": 10,
            "ssl": True,
            "sslmode": "verify-full",
        },
    },
    "logging": {
        "level": "INFO",
        "file": "/var/log/app.log",
        "handlers": {
            "console": {"enabled": True},
            "file": {"rotate": True, "max_bytes": 1048576},
        },
    },
}

print("===== expand=False =====")
print()
pprint(config)

print()

print("===== expand=True =====")
print()
pprint(config, expand=True)

main produces:

{'database': {'host': 'db.example.com',
              'options': {'connect_timeout': 5,
                          'pool_size': 10,
                          'ssl': True,
                          'sslmode': 'verify-full'},
              'port': 5432},
 'logging': {'file': '/var/log/app.log',
             'handlers': {'console': {'enabled': True},
                          'file': {'max_bytes': 1048576, 'rotate': True}},
             'level': 'INFO'}}

This PR produces:

{
    'database': {
        'host': 'db.example.com',
        'options': {'connect_timeout': 5, 'pool_size': 10, 'ssl': True, 'sslmode': 'verify-full'},
        'port': 5432,
    },
    'logging': {
        'file': '/var/log/app.log',
        'handlers': {'console': {'enabled': True}, 'file': {'max_bytes': 1048576, 'rotate': True}},
        'level': 'INFO',
    },
}

• Issue: Modern defaults for pprint #149189

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32490464 | 📁 Comparing bc0d9da against main (cc5f8b5)

  🔍 Preview build  

10 files changed · ± 10 modified

± Modified

• contents.html
• download.html
• library/datatypes.html
• library/difflib.html
• library/pprint.html
• library/ssl.html
• library/unittest.mock.html
• tutorial/stdlib2.html
• whatsnew/3.15.html
• whatsnew/changelog.html

[sobolevn]

I fully support this feature! I never used pprint, because I always thought that it is not actually pretty. Multilple nesting levels were really hard to read, indentation was hard to follow.

The only downside that, I think, we should empathise in the "What's new" is that this can break doctests. Let's maybe add a section on how one can restore the old behavior for all versions of Python?