dis(): Simplified stack emulation a bit.
diff --git a/Lib/pickletools.py b/Lib/pickletools.py
index 31c62b6..7eaa1a5 100644
--- a/Lib/pickletools.py
+++ b/Lib/pickletools.py
@@ -1898,15 +1898,19 @@
opcode.name)
maxproto = max(maxproto, opcode.proto)
-
- # See whether a MARK should be popped.
before = opcode.stack_before # don't mutate
after = opcode.stack_after # don't mutate
+ numtopop = len(before)
+
+ # See whether a MARK should be popped.
markmsg = None
if markobject in before or (opcode.name == "POP" and
stack and
stack[-1] is markobject):
assert markobject not in after
+ if __debug__:
+ if markobject in before:
+ assert before[-1] is stackslice
if markstack:
markpos = markstack.pop()
if markpos is None:
@@ -1917,19 +1921,18 @@
while stack[-1] is not markobject:
stack.pop()
stack.pop()
- # Remove markobject stuff from stack_before.
+ # Stop later code from popping too much.
try:
- i = before.index(markobject)
- before = before[:i]
+ numtopop = before.index(markobject)
except ValueError:
assert opcode.name == "POP"
- assert len(before) == 1
- before = [] # stop code later from popping again
+ numtopop = 0
else:
errormsg = markmsg = "no MARK exists on stack"
# Check for correct memo usage.
if opcode.name in ("PUT", "BINPUT", "LONG_BINPUT"):
+ assert arg is not None
if arg in memo:
errormsg = "memo key %r already defined" % arg
elif not stack:
@@ -1961,14 +1964,13 @@
raise ValueError(errormsg)
# Emulate the stack effects.
- n = len(before)
- if len(stack) < n:
- raise ValueError("tried to pop %d items from stack with "
- "only %d items" % (n, len(stack)))
- if n:
- del stack[-n:]
+ if len(stack) < numtopop:
+ raise ValueError("tries to pop %d items from stack with "
+ "only %d items" % (numtopop, len(stack)))
+ if numtopop:
+ del stack[-numtopop:]
if markobject in after:
- assert markobject not in opcode.stack_before
+ assert markobject not in before
markstack.append(pos)
stack.extend(after)