upstream/mercurial-mirror Files · contrib/bdiff-torture.py

rust-cpython: mark all PyLeaked methods as unsafe...

rust-cpython: mark all PyLeaked methods as unsafe Unfortunately, these methods can be abused to obtain the inner 'static reference. The simplest (pseudo-code) example is: let leaked: PyLeaked<&'static _> = shared.leak_immutable(); let static_ref: &'static _ = &*leaked.try_borrow(py)?; // PyLeakedRef::deref() tries to bound the lifetime to itself, but // the underlying data is a &'static reference, so the returned // reference can be &'static. This problem can be easily fixed by coercing the lifetime, but there are many other ways to achieve that, and there wouldn't be a generic solution: let leaked: PyLeaked<&'static [_]> = shared.leak_immutable(); let leaked_iter: PyLeaked<slice::Iter<'static, _>> = unsafe { leaked.map(|v| v.iter()) }; let static_slice: &'static [_] = leaked_iter.try_borrow(py)?.as_slice(); So basically I failed to design the safe borrowing interface. Maybe we'll instead have to add much more restricted interface on top of the unsafe PyLeaked methods? For instance, Iterator::next() could be implemented if its Item type is not &'a (where 'a may be cheated.) Anyway, this seems not an easy issue, so it's probably better to leave the current interface as unsafe, and get broader comments while upstreaming this feature.

Augie Fackler - - Load All Authors

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      # Randomized torture test generation for bdiff

      from __future__ import absolute_import, print_function

      import random

      import sys

      from mercurial import (

          mdiff,

          pycompat,

      )

      def reducetest(a, b):

          tries = 0

          reductions = 0

          print("reducing...")

          while tries < 1000:

              a2 = (

                  "\n".join(l for l in a.splitlines() if random.randint(0, 100) > 0)

                  + "\n"

              )

              b2 = (

                  "\n".join(l for l in b.splitlines() if random.randint(0, 100) > 0)

                  + "\n"

              )

              if a2 == a and b2 == b:

                  continue

              if a2 == b2:

                  continue

              tries += 1

              try:

                  test1(a, b)

              except Exception:

                  reductions += 1

                  tries = 0

                  a = a2

                  b = b2

          print("reduced:", reductions, len(a) + len(b), repr(a), repr(b))

          try:

              test1(a, b)

          except Exception as inst:

              print("failed:", inst)

          sys.exit(0)

      def test1(a, b):

          d = mdiff.textdiff(a, b)

          if not d:

              raise ValueError("empty")

          c = mdiff.patches(a, [d])

          if c != b:

              raise ValueError("bad")

      def testwrap(a, b):

          try:

              test1(a, b)

              return

          except Exception as inst:

              print("exception:", inst)

          reducetest(a, b)

      def test(a, b):

          testwrap(a, b)

          testwrap(b, a)

      def rndtest(size, noise):

          a = []

          src = "                aaaaaaaabbbbccd"

          for x in pycompat.xrange(size):

              a.append(src[random.randint(0, len(src) - 1)])

          while True:

              b = [c for c in a if random.randint(0, 99) > noise]

              b2 = []

              for c in b:

                  b2.append(c)

                  while random.randint(0, 99) < noise:

                      b2.append(src[random.randint(0, len(src) - 1)])

              if b2 != a:

                  break

          a = "\n".join(a) + "\n"

          b = "\n".join(b2) + "\n"

          test(a, b)

      maxvol = 10000

      startsize = 2

      while True:

          size = startsize

          count = 0

          while size < maxvol:

              print(size)

              volume = 0

              while volume < maxvol:

                  rndtest(size, 2)

                  volume += size

                  count += 2

              size *= 2

          maxvol *= 4

          startsize *= 4

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				# Randomized torture test generation for bdiff

				from __future__ import absolute_import, print_function
				import random
				import sys

				from mercurial import (
				mdiff,
				pycompat,
				)


				def reducetest(a, b):
				tries = 0
				reductions = 0
				print("reducing...")
				while tries < 1000:
				a2 = (
				"\n".join(l for l in a.splitlines() if random.randint(0, 100) > 0)
				+ "\n"
				)
				b2 = (
				"\n".join(l for l in b.splitlines() if random.randint(0, 100) > 0)
				+ "\n"
				)
				if a2 == a and b2 == b:
				continue
				if a2 == b2:
				continue
				tries += 1

				try:
				test1(a, b)
				except Exception:
				reductions += 1
				tries = 0
				a = a2
				b = b2

				print("reduced:", reductions, len(a) + len(b), repr(a), repr(b))
				try:
				test1(a, b)
				except Exception as inst:
				print("failed:", inst)

				sys.exit(0)


				def test1(a, b):
				d = mdiff.textdiff(a, b)
				if not d:
				raise ValueError("empty")
				c = mdiff.patches(a, [d])
				if c != b:
				raise ValueError("bad")


				def testwrap(a, b):
				try:
				test1(a, b)
				return
				except Exception as inst:
				print("exception:", inst)
				reducetest(a, b)


				def test(a, b):
				testwrap(a, b)
				testwrap(b, a)


				def rndtest(size, noise):
				a = []
				src = " aaaaaaaabbbbccd"
				for x in pycompat.xrange(size):
				a.append(src[random.randint(0, len(src) - 1)])

				while True:
				b = [c for c in a if random.randint(0, 99) > noise]
				b2 = []
				for c in b:
				b2.append(c)
				while random.randint(0, 99) < noise:
				b2.append(src[random.randint(0, len(src) - 1)])
				if b2 != a:
				break

				a = "\n".join(a) + "\n"
				b = "\n".join(b2) + "\n"

				test(a, b)


				maxvol = 10000
				startsize = 2
				while True:
				size = startsize
				count = 0
				while size < maxvol:
				print(size)
				volume = 0
				while volume < maxvol:
				rndtest(size, 2)
				volume += size
				count += 2
				size *= 2
				maxvol *= 4
				startsize *= 4