From patchwork Wed Jul 8 06:58:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [1,of,2,stable] demandimport: ignore `lzma` module for demandimport From: Manuel Jacob X-Patchwork-Id: 46654 Message-Id: To: mercurial-devel@mercurial-scm.org Date: Wed, 08 Jul 2020 08:58:29 +0200 # HG changeset patch # User Manuel Jacob # Date 1594189530 -7200 # Wed Jul 08 08:25:30 2020 +0200 # Branch stable # Node ID fd73d5b6e982804810e2399b4e16c6f104bf1d3c # Parent b1a1702262c93fe5879865dad43bd1016b1397b5 # EXP-Topic lzma demandimport: ignore `lzma` module for demandimport This makes importing the module fail if the `_lzma` module is not present. This makes e.g. tarfile correctly recognize if LZMA support is not present. It changes the exception File "/usr/lib/python3.6/tarfile.py", line 1694, in xzopen fileobj = lzma.LZMAFile(fileobj or name, mode, preset=preset) AttributeError: module 'lzma' has no attribute 'LZMAFile' to the more correct exception File "/usr/lib/python3.6/tarfile.py", line 1692, in xzopen raise CompressionError("lzma module is not available") tarfile.CompressionError: lzma module is not available Also, it prevents that the error "abort: No module named '_lzma'!" is shown when a development warning is to be shown. The reason why that happened is that for showing the warning, we get information about the stack frames from the inspect module, which accesses the `__file__` attribute of all modules in `sys.modules` to build some cache, causing all modules (including `lzma`) to be imported. diff --git a/hgdemandimport/__init__.py b/hgdemandimport/__init__.py --- a/hgdemandimport/__init__.py +++ b/hgdemandimport/__init__.py @@ -56,6 +56,7 @@ '__builtin__', 'builtins', 'urwid.command_map', # for pudb + 'lzma', } _pypy = '__pypy__' in sys.builtin_module_names