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fix(django-spanner): backslash-escape string literals in quote_value #18234

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fix(django-spanner): backslash-escape string literals in quote_value #18234

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5 changes: 4 additions & 1 deletion packages/django-google-spanner/django_spanner/schema.py
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Original file line number Diff line number Diff line change
Expand Up @@ -450,7 +450,10 @@ def add_index(self, model, index):
def quote_value(self, value):
# A more complete implementation isn't currently required.
if isinstance(value, str):
return "'%s'" % value.replace("'", "''")
# GoogleSQL string literals use backslash escaping; '' quote
# doubling is not recognized, so escape the backslash first and
# then the quote (matching the db_default/generated inlining above).
return "'%s'" % value.replace("\\", "\\\\").replace("'", "\\'")

@gemini-code-assist gemini-code-assist Bot Aug 27, 2026

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medium

In GoogleSQL, single-quoted string literals cannot contain literal newlines (\n) or carriage returns (\r). If a string containing these characters is passed to quote_value, it will result in a syntax error in Spanner. To prevent this, we should also escape newlines and carriage returns.

Suggested change
return "'%s'" % value.replace("\\", "\\\\").replace("'", "\\'")
return "'%s'" % value.replace("\\", "\\\\").replace("'", "\\'").replace("\n", "\\n").replace("\r", "\\r")

@sakthivelmanii sakthivelmanii Sep 4, 2026

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@Samin061 can you address this comment as well?

@olavloite olavloite Sep 4, 2026

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In GoogleSQL, single-quoted string literals cannot contain literal unescaped newlines (\n) or carriage returns (\r). If a multiline default or comment is passed to quote_value, it causes a syntax error in Spanner DDL. Please escape them using .replace("\n", "\\n").replace("\r", "\\r") (matching what you did in PR #18205).

Also add this test to verify:

def test_quote_value_escapes_newlines_and_carriage_returns(self):
    schema_editor = DatabaseSchemaEditor(self.connection)
    self.assertEqual(
        schema_editor.quote_value("line1\nline2"),
        "'line1\\nline2'",
    )
    self.assertEqual(
        schema_editor.quote_value("line1\r\nline2"),
        "'line1\\r\\nline2'",
    )

if isinstance(value, bool):
return "TRUE" if value else "FALSE"
return str(value)

@olavloite olavloite Sep 4, 2026

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Not directly part of this change, but still: quote_value falls through to str(value) when value is None, returning the literal string "None" instead of SQL "NULL". In GoogleSQL DDL, DEFAULT (None) causes a syntax/name-resolution error. Please handle None explicitly by returning "NULL".

Similar problems also occur for Date, Timestamp and Bytes.

Add these tests to verify:

def test_quote_value_handles_none(self):
    schema_editor = DatabaseSchemaEditor(self.connection)
    self.assertEqual(schema_editor.quote_value(None), "NULL")

import datetime
def test_quote_value_handles_date_and_datetime(self):
    schema_editor = DatabaseSchemaEditor(self.connection)
    self.assertEqual(
        schema_editor.quote_value(datetime.date(2026, 9, 4)),
        "'2026-09-04'",
    )
    self.assertEqual(
        schema_editor.quote_value(datetime.datetime(2026, 9, 4, 12, 0, 0)),
        "'2026-09-04 12:00:00'",
    )

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13 changes: 13 additions & 0 deletions packages/django-google-spanner/tests/unit/django_spanner/test_schema.py
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,19 @@ def test_quote_value(self):
schema_editor = DatabaseSchemaEditor(self.connection)
self.assertEqual(schema_editor.quote_value(value=1.1), "1.1")

def test_quote_value_escapes_string(self):

@olavloite olavloite Sep 4, 2026

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Also add:

def test_quote_value_booleans(self):
    schema_editor = DatabaseSchemaEditor(self.connection)
    self.assertEqual(schema_editor.quote_value(True), "TRUE")
    self.assertEqual(schema_editor.quote_value(False), "FALSE")

def test_prepare_default_delegates_to_quote_value(self):
    schema_editor = DatabaseSchemaEditor(self.connection)
    self.assertEqual(schema_editor.prepare_default("o'brien"), "'o\\'brien'")
    self.assertEqual(schema_editor.prepare_default(True), "TRUE")

"""
String literals must be backslash-escaped for GoogleSQL. A quote or
backslash in the value must not be able to terminate the literal.
"""
schema_editor = DatabaseSchemaEditor(self.connection)
self.assertEqual(schema_editor.quote_value(value="o'brien"), "'o\\'brien'")
self.assertEqual(schema_editor.quote_value(value="a\\b"), "'a\\\\b'")
self.assertEqual(
schema_editor.quote_value(value="\\'; DROP TABLE t; --"),
"'\\\\\\'; DROP TABLE t; --'",
)

def test_skip_default(self):
"""
Tries skipping default as Cloud spanner doesn't support it.
Expand Down
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