tutil: assert that Decimal precision is sufficient - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
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DIR commit 24d47022b465705c710c5fa92f6e46d21d4b380c
DIR parent b856336f8ce868717457676112a453b370eb9408
HTML Author: SomberNight <somber.night@protonmail.com>
Date: Thu, 18 Feb 2021 02:40:21 +0100
util: assert that Decimal precision is sufficient
Just for sanity... e.g. when importing electrum as a python library,
tthe calling code could have changed the precision.
related: #5223
Diffstat:
M electrum/util.py | 7 +++++++
1 file changed, 7 insertions(+), 0 deletions(-)
---
DIR diff --git a/electrum/util.py b/electrum/util.py
t@@ -630,6 +630,13 @@ def format_satoshis_plain(x, *, decimal_point=8) -> str:
return "{:.8f}".format(Decimal(x) / scale_factor).rstrip('0').rstrip('.')
+# Check that Decimal precision is sufficient.
+# We need at the very least ~20, as we deal with msat amounts, and
+# log10(21_000_000 * 10**8 * 1000) ~= 18.3
+# decimal.DefaultContext.prec == 28 by default, but it is mutable.
+# We enforce that we have at least that available.
+assert decimal.getcontext().prec >= 28, f"PyDecimal precision too low: {decimal.getcontext().prec}"
+
DECIMAL_POINT = localeconv()['decimal_point'] # type: str