trace: $prefix and $exec_prefix improperly replaced on Fedora

[mathstuf]

BPO	21016
Nosy	@vstinner, @mathstuf, @miss-islington
PRs	bpo-21016: pydoc and trace use sysconfig #18476 [3.8] bpo-21016: pydoc and trace use sysconfig (GH-18476) #18482 [3.7] bpo-21016: pydoc and trace use sysconfig (GH-18476) #18483

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2020-02-12.12:33:38.151>
created_at = <Date 2014-03-22.03:46:20.443>
labels = ['type-bug', 'library']
title = 'trace: $prefix and $exec_prefix improperly replaced on Fedora'
updated_at = <Date 2020-02-13.08:35:46.753>
user = 'https://github.com/mathstuf'

bugs.python.org fields:

activity = <Date 2020-02-13.08:35:46.753>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2020-02-12.12:33:38.151>
closer = 'vstinner'
components = ['Library (Lib)']
creation = <Date 2014-03-22.03:46:20.443>
creator = 'mathstuf'
dependencies = []
files = []
hgrepos = []
issue_num = 21016
keywords = ['patch']
message_count = 7.0
messages = ['214435', '361881', '361887', '361889', '361891', '361941', '361946']
nosy_count = 3.0
nosy_names = ['vstinner', 'mathstuf', 'miss-islington']
pr_nums = ['18476', '18482', '18483']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue21016'
versions = ['Python 2.7', 'Python 3.3']

[mathstuf]

In the --ignore-dir handling of trace.py, the following is done:

                s = s.replace("$prefix",
                              os.path.join(sys.base_prefix, "lib",
                                           "python" + sys.version[:3]))
                s = s.replace("$exec_prefix",
                              os.path.join(sys.base_exec_prefix, "lib",
                                           "python" + sys.version[:3]))

This does not do what is expected on 64-bit Fedora and newer Debian since the proper directory is /usr/lib64/python2.7 or /usr/lib/$triple/python2.7. Just the libsuffix can't be changed either since Fedora also has /usr/lib/python2.7 for arch-independent modules. It'd be nice if $prefix were replaced with the following directories from sysconfig.get_paths(): platstdlib, platlib, purelib, and stdlib.

It also erroneously replaces things like '$prefixpath'. It should probably do split the path on the path separators and only replace components that are equal to $prefix or $exec_prefix (so that the '$' can be escaped for directories named as such literally, but that would require a pass to parse the escapes).

[vstinner]

New changeset 4fac7ed by Victor Stinner in branch 'master':
bpo-21016: pydoc and trace use sysconfig (GH-18476)
4fac7ed

[miss-islington]

New changeset ca133e5 by Miss Islington (bot) in branch '3.7':
bpo-21016: pydoc and trace use sysconfig (GH-18476)
ca133e5

[miss-islington]

New changeset ac6f4d2 by Miss Islington (bot) in branch '3.8':
bpo-21016: pydoc and trace use sysconfig (GH-18476)
ac6f4d2

[vstinner]

Thanks Ben Boeckel for the bugfix. Sorry for the delay (6 years)! But it's now fixed in 3.7, 3.8 and master branches.

[mathstuf]

Thanks!

Should I file a new issue for the other (less urgent) problem mentioned at the bottom or is it not really worth fixing?

It also erroneously replaces things like '$prefixpath'. It should probably do split the path on the path separators and only replace components that are equal to $prefix or $exec_prefix (so that the '$' can be escaped for directories named as such literally, but that would require a pass to parse the escapes).

[vstinner]

It also erroneously replaces things like '$prefixpath'. It should probably do split the path on the path separators and only replace components that are equal to $prefix or $exec_prefix (so that the '$' can be escaped for directories named as such literally, but that would require a pass to parse the escapes).

re.sub() can be used to leave $prefixpath unchanged. Yeah, please open a separed issue. Sorry, I missed this part of the bug report.