Use lowercase hex numbers fixes #1692 (#1775)

* Made hex lower case

* Refactored numeric formatting section

* Redid some refactoring and removed bloat

* Removed additions from test_requirements.txt

* Primer now expects expected changes

* Undid some refactoring

* added to changelog

* Update src/black/__init__.py

Co-authored-by: Zsolt Dollenstein <zsol.zsol@gmail.com>

Co-authored-by: Zsolt Dollenstein <zsol.zsol@gmail.com>
Co-authored-by: Cooper Lees <me@cooperlees.com>

.gitignore

@@ -1,3 +1,4 @@
+.venv
 .coverage
 _build
 .DS_Store

CHANGES.md

@@ -21,6 +21,8 @@
 
 - Added support for PEP 614 relaxed decorator syntax on python 3.9 (#1711)
 
+- use lowercase hex strings (#1692)
+
 #### _Packaging_
 
 - Self-contained native _Black_ binaries are now provided for releases via GitHub

src/black/__init__.py

@@ -5192,10 +5192,31 @@ def normalize_numeric_literal(leaf: Leaf) -> None:
         # Leave octal and binary literals alone.
         pass
     elif text.startswith("0x"):
-        # Change hex literals to upper case.
-        before, after = text[:2], text[2:]
-        text = f"{before}{after.upper()}"
+        text = format_hex(text)
     elif "e" in text:
+        text = format_scientific_notation(text)
+    elif text.endswith(("j", "l")):
+        text = format_long_or_complex_number(text)
+    else:
+        text = format_float_or_int_string(text)
+    leaf.value = text
+
+
+def format_hex(text: str) -> str:
+    """
+    Formats a hexadecimal string like "0x12b3"
+
+    Uses lowercase because of similarity between "B" and "8", which
+    can cause security issues.
+    see: https://github.com/psf/black/issues/1692
+    """
+
+    before, after = text[:2], text[2:]
+    return f"{before}{after.lower()}"
+
+
+def format_scientific_notation(text: str) -> str:
+    """Formats a numeric string utilizing scentific notation"""
     before, after = text.split("e")
     sign = ""
     if after.startswith("-"):
@@ -5204,17 +5225,17 @@ def normalize_numeric_literal(leaf: Leaf) -> None:
     elif after.startswith("+"):
         after = after[1:]
     before = format_float_or_int_string(before)
-        text = f"{before}e{sign}{after}"
-    elif text.endswith(("j", "l")):
+    return f"{before}e{sign}{after}"
+
+
+def format_long_or_complex_number(text: str) -> str:
+    """Formats a long or complex string like `10L` or `10j`"""
     number = text[:-1]
     suffix = text[-1]
     # Capitalize in "2L" because "l" looks too similar to "1".
     if suffix == "l":
         suffix = "L"
-        text = f"{format_float_or_int_string(number)}{suffix}"
-    else:
-        text = format_float_or_int_string(text)
-    leaf.value = text
+    return f"{format_float_or_int_string(number)}{suffix}"
 
 
 def format_float_or_int_string(text: str) -> str:

src/black_primer/primer.json

@@ -10,7 +10,7 @@
     },
     "attrs": {
       "cli_arguments": [],
-      "expect_formatting_changes": false,
+      "expect_formatting_changes": true,
       "git_clone_url": "https://github.com/python-attrs/attrs.git",
       "long_checkout": false,
       "py_versions": ["all"]
@@ -47,7 +47,7 @@
     },
     "hypothesis": {
       "cli_arguments": [],
-      "expect_formatting_changes": false,
+      "expect_formatting_changes": true,
       "git_clone_url": "https://github.com/HypothesisWorks/hypothesis.git",
       "long_checkout": false,
       "py_versions": ["all"]
@@ -63,7 +63,7 @@
     },
     "pillow": {
       "cli_arguments": [],
-      "expect_formatting_changes": false,
+      "expect_formatting_changes": true,
       "git_clone_url": "https://github.com/python-pillow/Pillow.git",
       "long_checkout": false,
       "py_versions": ["all"]
@@ -77,7 +77,7 @@
     },
     "pyramid": {
       "cli_arguments": [],
-      "expect_formatting_changes": false,
+      "expect_formatting_changes": true,
       "git_clone_url": "https://github.com/Pylons/pyramid.git",
       "long_checkout": false,
       "py_versions": ["all"]
@@ -112,7 +112,7 @@
     },
     "virtualenv": {
       "cli_arguments": [],
-      "expect_formatting_changes": false,
+      "expect_formatting_changes": true,
       "git_clone_url": "https://github.com/pypa/virtualenv.git",
       "long_checkout": false,
       "py_versions": ["all"]

src/blib2to3/pytree.py

@@ -34,7 +34,7 @@
 import sys
 from io import StringIO
 
-HUGE: int = 0x7FFFFFFF  # maximum repeat count, default max
+HUGE: int = 0x7fffffff  # maximum repeat count, default max
 
 _type_reprs: Dict[int, Union[Text, int]] = {}
 

tests/data/numeric_literals.py

@@ -12,7 +12,7 @@
 x = 123456789E123456789
 x = 123456789J
 x = 123456789.123456789J
-x = 0XB1ACC
+x = 0Xb1aCc
 x = 0B1011
 x = 0O777
 x = 0.000000006
@@ -36,7 +36,7 @@
 x = 123456789e123456789
 x = 123456789j
 x = 123456789.123456789j
-x = 0xB1ACC
+x = 0xb1acc
 x = 0b1011
 x = 0o777
 x = 0.000000006

tests/data/numeric_literals_py2.py

@@ -3,7 +3,7 @@
 x = 123456789L
 x = 123456789l
 x = 123456789
-x = 0xb1acc
+x = 0xB1aCc
 
 # output
 
@@ -13,4 +13,4 @@
 x = 123456789L
 x = 123456789L
 x = 123456789
-x = 0xB1ACC
+x = 0xb1acc

tests/data/numeric_literals_skip_underscores.py

@@ -3,7 +3,7 @@
 x = 123456789
 x = 1_2_3_4_5_6_7
 x = 1E+1
-x = 0xb1acc
+x = 0xb1AcC
 x = 0.00_00_006
 x = 12_34_567J
 x = .1_2
@@ -16,7 +16,7 @@
 x = 123456789
 x = 1_2_3_4_5_6_7
 x = 1e1
-x = 0xB1ACC
+x = 0xb1acc
 x = 0.00_00_006
 x = 12_34_567j
 x = 0.1_2