EngineTest.ScenarioStreamRedirect fails with a LookupException

Open
#906 1 comment 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
csharp, python
Domain
backend

Research direction

Start by reproducing EngineTest.ScenarioStreamRedirect and inspect the named _codecs.lookup, io.TextIOWrapper, StringOps.TryGetEncoding, and PythonOps.LookupEncoding paths. Compare why cp437 works through bytes.decode/str.encode but fails through the stream path; done means the scenario no longer raises LookupException.

Written by the indexing model from the issue text.

Description

It looks like this is due to the the standard library not being available and so none of the codecs are available via _codecs.lookup. The failure occurs even though the particular encoding causing the failure (cp437) is available to use via bytes.decode/str.encode. This is because io.TextIOWrapper does not make use of the StringOps.TryGetEncoding mechanism but instead relies on PythonOps.LookupEncoding.

Related to https://github.com/IronLanguages/ironpython2/issues/659 (probably the same issue)

@BCSharp not sure if this something you encountered before?

Dominant language
C#
Stars
2.8k
Forks
316
Avg merge
1d 9h
Merged PRs (30d)
1

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from IronLanguages/ironpython3

All issues in IronLanguages/ironpython3

Similar issues

More C# issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.