Returning 1 from the set_progress_handler handler cancels query

[simonw]

This behaviour is currently undocumented by Python, but is covered in the SQLite docs here: https://sqlite.org/c3ref/progress_handler.html

[the-knights-who-say-ni]

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[simonw]

Since this is just a tiny documentation fix, I think it warrants the "skip issue" and "skip news" labels.

[simonw]

From the history of this file, I think @berkerpeksag may be a good person to review this.

[berkerpeksag]

Good catch, thank you! This is indeed a tested but undocumented feature:

cpython/Lib/sqlite3/test/hooks.py

Lines 175 to 189 in 4f469c0

	def CheckCancelOperation(self):
	"""
	Test that returning a non-zero value stops the operation in progress.
	"""
	con = sqlite.connect(":memory:")
	progress_calls = []
	def progress():
	progress_calls.append(None)
	return 1
	con.set_progress_handler(progress, 1)
	curs = con.cursor()
	self.assertRaises(
	sqlite.OperationalError,
	curs.execute,
	"create table bar (a, b)")

[berkerpeksag]

:exc:`sqlite3.OperationalError`

[miss-islington]

Thanks @simonw for the PR, and @berkerpeksag for merging it 🌮🎉.. I'm working now to backport this PR to: 3.6.
🐍🍒⛏🤖

[berkerpeksag]

Thanks!

[bedevere-bot]

GH-4229 is a backport of this pull request to the 3.6 branch.