Warn about discontinued packages on pub get/upgrade (#2835)

The responses from the version listings are cached in the pub cache, such that we don't have to re-query the server on a pub get where pubspec.lock already exists and the packages are in cache already.

The cached responses are stored as a json object:

```
{
  ...<body>
  "_fetchedAt": Iso8601String
}
```

The cached file will be at `<PUB_CACHE>/hosted/<url>/.cache/<package-name>-versions.json`

.cache is chosen such that older versions of pub will not see them as a broken package (listDir ignores files starting wit a dot).

where body is the decoded response from the server.

Gives a maximum delay of the discontinued warning of 3 days from the actual discontinuation.

To see if a cached response is too old we both check the file modified timestamp (for speed) and the json timestamp (for extra robustness).

One hope is that the cached responses can be used for speeding up pub get itself, if/when we have a faster way of checking if the package-listing is up-to-date...
13 files changed
tree: 77f50219086ee6f1db725b0ab3552eb516100467
  1. .github/
  2. bin/
  3. doc/
  4. lib/
  5. test/
  6. tool/
  7. .gitignore
  8. .status
  9. .test_config
  10. analysis_options.yaml
  11. AUTHORS
  12. CONTRIBUTING.md
  13. dart_test.yaml
  14. LICENSE
  15. pubspec.yaml
  16. README.md
README.md

Build Status

Pub is the package manager for Dart.

Contributing to pub

Thanks for being interested in contributing to pub! Contributing to a new project can be hard: there's a lot of new code and practices to learn. This document is intended to get you up and running as quickly as possible. For more information, see the pub tool documentation.

The first step towards contributing is to contact the pub dev team and let us know what you‘re working on, so we can be sure not to start working on the same thing at the same time. Open an issue letting us know that you’re interested in contributing and what you plan on working on. This will also let us give you specific advice about where to start.

Organization

Pub isn‘t a package, but it’s organized like one. It has four top-level directories:

  • lib/ contains the implementation of pub. Currently, it's all in lib/src/, since there are no libraries intended for public consumption.

  • test/ contains the tests for pub.

  • bin/ contains pub.dart, the entrypoint script that's run whenever a user types “pub” on the command line or runs it in the Dart editor. This is usually run through shell scripts in sdk/bin at the root of the Dart repository.

It's probably easiest to start diving into the codebase by looking at a particular pub command. Each command is encapsulated in files in lib/src/command/.

Running pub

To run pub from the Git repository, run:

dart bin/pub.dart

Testing pub

Before any change is made to pub, all tests should pass. To run a pub test, run:

dart tool/test.dart test/path/to_test.dart

To run all tests at once, run:

dart tool/test.dart

Changes to pub should be accompanied by one or more tests that exercise the new functionality. When adding a test, the best strategy is to find a similar test in test/ and follow the same patterns.

Pub tests come in two basic forms. The first, which is usually used to unit test classes and libraries internal to pub, has many tests in a single file. This is used when each test will take a short time to run. For example, test/version_test.dart contains unit tests for pub's Version class.

The other form, used by most pub tests, is usually used for integration tests of user-visible pub commands. Each test has a file to itself, which is named after the test description. This is used when tests can take a long time to run to avoid having the tests time out when running on the build bots. For example, tests/get/hosted/get_transitive_test.dart tests the resolution of transitive hosted dependencies when using pub get.

Landing your patch

All patches to official Dart packages, including to pub, need to undergo code review before they're submitted. The full process for putting up your patch for review is documented elsewhere.