From a519a21f04cfa0cc783bd37ffd5ee90ce1078f2e Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Tue, 1 Mar 2022 18:43:26 -0500
Subject: [PATCH] Remove floating point from our understanding of SQL
Arguably we never really understood it anyway.
---
src/_zkapauthorizer/tests/sql.py | 8 +++++++-
src/_zkapauthorizer/tests/strategies.py | 15 +--------------
2 files changed, 8 insertions(+), 15 deletions(-)
diff --git a/src/_zkapauthorizer/tests/sql.py b/src/_zkapauthorizer/tests/sql.py
index 13b5a26..0745de8 100644
--- a/src/_zkapauthorizer/tests/sql.py
+++ b/src/_zkapauthorizer/tests/sql.py
@@ -17,10 +17,16 @@ class StorageAffinity(Enum):
column.
"""
+ # Notably, this excludes REAL because I don't know how to get floating
+ # point values to round-trip through the snapshot/recover implementation
+ # on Windows. ZKAPAuthorizer itself doesn't need REAL / floating point
+ # values so this limitation doesn't bother us in practice (ideally
+ # something somewhere would enforce this so no one accidentally starts
+ # using floating point values thinking the system will handle them).
+
INT = auto()
TEXT = auto()
BLOB = auto()
- REAL = auto()
NUMERIC = auto()
diff --git a/src/_zkapauthorizer/tests/strategies.py b/src/_zkapauthorizer/tests/strategies.py
index 5b447a5..397c901 100644
--- a/src/_zkapauthorizer/tests/strategies.py
+++ b/src/_zkapauthorizer/tests/strategies.py
@@ -1224,18 +1224,6 @@ def tables() -> SearchStrategy[Table]:
# https://www.sqlite.org/floatingpoint.html#how_sqlite_stores_numbers
_sql_integer = integers(min_value=-(2 ** 63) + 1, max_value=2 ** 63 - 1)
-# SQLite3 can do infinity and NaN but I don't know how to get them through the
-# Python interface. SQLite3 can do 64 bit floats but it only guarantees 15
-# digits of precision (maybe only for its base 10 string representations?)
-# which causes values requiring greater precision to fail to round-trip. The
-# SQLite3 docs are quite clear about what one should expect from floating
-# point values, anyway:
-#
-# Floating point values are approximate.
-#
-# https://www.sqlite.org/floatingpoint.html
-_sql_floats = floats(allow_infinity=False, allow_nan=False, width=32)
-
# Exclude surrogates because SQLite3 uses UTF-8 and we don't need them. Also
# they have to come in correctly formed pairs to be legal anyway and it's
# inconvenient to do that with text.
@@ -1261,8 +1249,7 @@ _storage_affinity_strategies = {
StorageAffinity.INT: _sql_integer,
StorageAffinity.TEXT: _sql_text,
StorageAffinity.BLOB: binary(),
- StorageAffinity.REAL: _sql_floats,
- StorageAffinity.NUMERIC: one_of(_sql_integer, _sql_floats),
+ StorageAffinity.NUMERIC: _sql_integer,
}
--
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