Improve StackFrame type hints

MozillaSecurity · May 9, 2024 · e3c1042 · e3c1042
1 parent adf48c4
commit e3c1042
Show file tree

Hide file tree

Showing 2 changed files with 34 additions and 12 deletions.
diff --git a/grizzly/common/stack_hasher.py b/grizzly/common/stack_hasher.py
@@ -11,12 +11,13 @@
 crash id (1st hash) and a bug id (2nd hash). This is not perfect but works very
 well in most cases.
 """
+from abc import ABC, abstractmethod
 from hashlib import sha1
 from logging import DEBUG, INFO, basicConfig, getLogger
 from os.path import basename
 from re import compile as re_compile
 from re import match as re_match
-from typing import List, Optional
+from typing import List, Optional, Type
 
 __all__ = ("Stack",)
 __author__ = "Tyson Smith"
@@ -37,7 +38,7 @@
 _RE_FUNC_NAME = re_compile(r"(?P<func>.+?)[\(|\s|\<]{1}")
 
 
-class StackFrame:
+class StackFrame(ABC):
     __slots__ = ("function", "location", "offset", "stack_line")
 
     def __init__(
@@ -64,6 +65,18 @@ def __str__(self) -> str:
             out.append(f"offset: {self.offset!r}")
         return " - ".join(out)
 
+    @classmethod
+    @abstractmethod
+    def from_line(cls, input_line: str) -> Optional["StackFrame"]:
+        """Parse stack frame details.
+
+        Args:
+            input_line: A single line of text.
+
+        Returns:
+            StackFrame
+        """
+
 
 class MinidumpStackFrame(StackFrame):
     @classmethod
@@ -402,13 +415,13 @@ def from_text(cls, input_text: str, major_depth: int = MAJOR_DEPTH) -> "Stack":
         """
 
         frames: List[StackFrame] = []
-        parser_class = None
+        parser_class: Optional[Type[StackFrame]] = None
         for line in input_text.split("\n"):
             line = line.rstrip()
             if not line:
                 # skip empty lines
                 continue
-            frame = None
+            frame: Optional[StackFrame] = None
             try:
                 # only use a single StackFrame type
                 if parser_class is None:
@@ -424,8 +437,8 @@ def from_text(cls, input_text: str, major_depth: int = MAJOR_DEPTH) -> "Stack":
                     ):
                         frame = frame_parser.from_line(line)
                         if frame is not None:
+                            LOG.debug("frame parser: %s", frame_parser.__name__)
                             parser_class = frame_parser
-                            LOG.debug("frame parser: %s", parser_class.__name__)
                             break
                 else:
                     frame = parser_class.from_line(line)

diff --git a/grizzly/common/test_stack_hasher.py b/grizzly/common/test_stack_hasher.py
@@ -17,6 +17,13 @@
 )
 
 
+class BasicStackFrame(StackFrame):
+    @classmethod
+    def from_line(cls, input_line):
+        # unused
+        pass
+
+
 def test_stack_01():
     """test creating an empty Stack"""
     stack = Stack([])
@@ -27,7 +34,7 @@ def test_stack_01():
 
 def test_stack_02():
     """test creating a Stack with 1 generic frame"""
-    frames = [StackFrame(function="a", location="b", offset="c", stack_line="0")]
+    frames = [BasicStackFrame(function="a", location="b", offset="c", stack_line="0")]
     stack = Stack(frames)
     assert stack.minor is not None
     assert stack.major is not None
@@ -44,7 +51,7 @@ def test_stack_02():
 def test_stack_03():
     """test creating a Stack with 2 frames"""
     frames = [
-        StackFrame(function="a", location="b", offset="c", stack_line="0")
+        BasicStackFrame(function="a", location="b", offset="c", stack_line="0")
         for _ in range(2)
     ]
     stack = Stack(frames, major_depth=2)
@@ -59,7 +66,7 @@ def test_stack_03():
 def test_stack_04():
     """test creating a Stack with 2 frames with a major depth of 0"""
     frames = [
-        StackFrame(function="a", location="b", offset="c", stack_line=str(line))
+        BasicStackFrame(function="a", location="b", offset="c", stack_line=str(line))
         for line in range(2)
     ]
     stack = Stack(frames, major_depth=0)
@@ -74,7 +81,7 @@ def test_stack_04():
 def test_stack_05():
     """test creating a Stack with 10 frames exceeding major depth"""
     frames = [
-        StackFrame(function="a", location="b", offset="c", stack_line=str(line))
+        BasicStackFrame(function="a", location="b", offset="c", stack_line=str(line))
         for line in range(10)
     ]
     stack = Stack(frames, major_depth=5)
@@ -284,7 +291,9 @@ def test_stack_13():
 def test_stack_14():
     """test Stack.height_limit"""
     frames = [
-        StackFrame(function=str(num), location="b", offset="c", stack_line=str(num))
+        BasicStackFrame(
+            function=str(num), location="b", offset="c", stack_line=str(num)
+        )
         for num in range(10)
     ]
     stack = Stack(frames, major_depth=3)
@@ -379,8 +388,8 @@ def test_stack_18():
 
 
 def test_stackframe_01():
-    """test creating an empty generic StackFrame"""
-    stack = StackFrame()
+    """test creating an empty generic BasicStackFrame"""
+    stack = BasicStackFrame()
     assert not str(stack)