PackagingWG/2020-04-28-pip¶

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Resolver Dev Syncup (28 April 2020)

Participants:

Paul
Pradyun
Tzu-Ping

Agenda:

pip 20.1 release
test failures
- https://trello.com/b/tydA30lP/new-resolver-for-pip-fix-the-failing-tests (maybe do not include in public notes?)
20.1 and resolver work
- Merge the existing resolver PRs into a single PR so we can sort out the merge conflicts in advance. Paul will do this.
  - Paul will take a look at his monolithic merged PRs branch’s failures.
Visualization work
- Update on work / discussion on the visualization design
- Graphviz!!!
- Paul: Looks good.
- Tzu-Ping: Do we expect a random user to understand this graph?
  - Pradyun: no?
- Q: Where does this fit in?
  - Pradyun: beside resolvelib. maybe?
- https://github.com/sarugaku/resolvelib/issues/46#issuecomment-620106093

(bringing other discussions / past discussions)

pip upgrade package [package …]
- TP: Definitely better than pip install --upgrade{.backtick}—if we can ever convince the users :p
pip command to open project URL ( pypi.org/project/<name>/<version> ) to let the user have easy access to metadata.
- TP: Think about this again, the setup.py I want to read is almost never the frontmost code on GitHub (that’s master, I want a specific version). A more viable solution would be for Warehouse to implement a “view content in sdist” page, and we link to that.
- TP: Wiew wheel metadata is less useful because most people don’t understand Core Metadata format anyway
- TODO: TP files a feature request to Warehouse
Paul: We should try to not distract ourselves away from the tedious work of fixing the test failures though.
When pip install fails, dump a “postmortem” in a file instead of cluttering the console
- TP thinks this is a good idea, but we need to keep CI in mind (where the log file is not accessible, only the console)
- NPM and Yarn both dump an error file on failures, but they still puts up verbose messages in the console
- Pradyun: things to log:
  - choice made
  - discarding choice (backtracking)
  - note dependencies as discovered
  - I’m doing a download now! (TP thinks this is unnecessary)
- Paul: More thinking about dumping the “state of the resolver” at the time of the exception for analysis
  - Dependency graph, in some serialised (machine readable) form.
    - TP It can be difficult to decide “which” graph to dump on multiple backtracking. Maybe dump the graph on each backtracking?
  - Discarded candidates, maybe, if resolvelib still has a record of them.