[New-bugs-announce] [issue14385] Support other types than dict for __builtins__

[STINNER Victor]

New submission from STINNER Victor <victor.stinner at gmail.com>:

CPython expects __builtins__ to be a dict, but it is interesting to be able to use another type. For example, my pysandbox project (sandbox to secure Python) requires a read-only mapping for __builtins__.

The PEP 416 was rejected, so there is no builtin frozendict type, but it looks like the dictproxy type will be exposed as a public type.

Attached patch uses PyDict_CheckExact() to check if __builtins__ is a dict and add a "slow-path" for other types. The overhead on runtime performance should be very low (near zero), PyDict_CheckExact() just dereference a pointer (to read the object type) and compare two pointers.

The patch depends on issue #14383 patch (identifier.patch) for the __build_class__ identifier. I can write a new patch without this dependency if needed.

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components: Interpreter Core
files: builtins.patch
keywords: patch
messages: 156534
nosy: haypo
priority: normal
severity: normal
status: open
title: Support other types than dict for __builtins__
type: enhancement
versions: Python 3.3
Added file: http://bugs.python.org/file24989/builtins.patch

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<http://bugs.python.org/issue14385>
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