[Bug]: select_option(index=0) incorrectly interpreted as select_option(index=None)

[jinohkang-theori]

Version

1.48.0

Steps to reproduce

1. Call locator.select_option(index=0) on a locator.
2. Call locator.select_option(value="") on a locator.

Expected behavior

1. The first option (index 0) is selected.
2. The blank option (value "") is selected.

Actual behavior

1. All options are unselected, leaving an empty <select>, as if index=None is specified.
2. All options are unselected, leaving an empty <select>, as if value=None is specified.

Additional context

The convert_select_option_values function is implemented incorrectly:

playwright-python/playwright/_impl/_element_handle.py

Lines 395 to 406 in c4df71c

	if value:
	if isinstance(value, str):
	value = [value]
	options = (options or []) + list(map(lambda e: dict(valueOrLabel=e), value))
	if index:
	if isinstance(index, int):
	index = [index]
	options = (options or []) + list(map(lambda e: dict(index=e), index))
	if label:
	if isinstance(label, str):
	label = [label]
	options = (options or []) + list(map(lambda e: dict(label=e), label))

The value, index, and label should be checked for None, not its truthiness.

Minimal reproducer:

import base64
from playwright.sync_api import sync_playwright

TEST_HTML = b'''
<select>
    <option value="A">Option A</option>
    <option value="B">Option B</option>
    <option value="">Empty Option</option>
</select>
'''

with sync_playwright() as playwright:
    browser = playwright.chromium.launch()  # or firefox, or webkit
    page = browser.new_page()
    page.goto('data:text/html;base64,' + base64.b64encode(TEST_HTML).decode())

    index_choice = page.locator("select").select_option(value="A")
    assert index_choice == ["A"], index_choice # OK

    index_choice = page.locator("select").select_option(value="B")
    assert index_choice == ["B"], index_choice # OK

    index_choice = page.locator("select").select_option(index=2)
    assert index_choice == [""], index_choice # OK

    index_choice = page.locator("select").select_option(index=0)
    assert index_choice == ["A"], index_choice # FAIL

    index_choice = page.locator("select").select_option(value="")
    assert index_choice == [""], index_choice # FAIL

Environment

- Operating System: [Ubuntu 24.04]
- CPU: [x86_64]
- Browser: [All]
- Python Version: [3.12.3]

[mxschmitt]

Thank you for the great bug report and investigation!