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dev-practices.md

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Description

This page describes development practices for this codebase.

Linting

Most of our linters require babashka. Before running them, please install https://github.com/babashka/babashka#installation. To invoke all the linters in this section, run bb dev:lint.

Clojure code

To lint:

clojure -M:clj-kondo --lint src

We lint our Clojure(Script) code with https://github.com/clj-kondo/clj-kondo/. If you need to configure specific linters, see this documentation. Where possible, a global linting configuration is used and namespace specific configuration is avoided.

There are outstanding linting items that are currently ignored to allow linting the rest of the codebase in CI. These outstanding linting items should be addressed at some point:

  • Comments starting with TODO:lint
  • Code marked with #_:clj-kondo/ignore require a good understanding of the context to address as they usually involve something with a side effect or require changing multiple fns up the call stack.

Unused vars

We use https://github.com/borkdude/carve to detect unused vars in our codebase.

To run this linter:

bb lint:carve

By default, the script runs in CI mode which prints unused vars if they are found. The script can be run in an interactive mode which prompts for keeping (ignoring) an unused var or removing it. Run this mode with:

bb lint:carve '{:interactive true}'

When a var is ignored, it is added to .carve/ignore. Please add a comment for why a var is ignored to help others understand why it's unused.

Large vars

Large vars have a lot of complexity and make it hard for the team to maintain and understand them. To run this linter:

bb lint:large-vars

To configure the linter, see the [:tasks/config :large-vars] path of bb.edn.

Document namespaces

Documentation helps teams share their knowledge and enables more individuals to contribute to the codebase. Documenting our namespaces is a good first step to improving our documentation. To run this linter:

bb lint:ns-docstrings

To skip documenting a ns, use the common ^:no-doc metadata flag.

Datalog linting

We use datascript's datalog to power our modeling and querying layer. Since datalog is concise, it is easy to write something invalid. To avoid typos and other preventable mistakes, we lint our queries and rules. Our queries are linted through clj-kondo and datalog-parser. clj-kondo will error if it detects an invalid query.

Invalid translations

Our translations can be configured incorrectly. We can catch some of these mistakes as noted here.

Testing

We have unit and end to end tests.

End to End Tests

To run end to end tests

yarn electron-watch
# in another shell
yarn e2e-test # or npx playwright test

If e2e failed after first running:

If e2e tests fail, they can be debugged by examining a trace dump with the playwright trace viewer. Locally this will get dumped into e2e-dump/. On CI the trace file will be under Artifacts at the bottom of a run page e.g. https://github.com/logseq/logseq/actions/runs/3574600322.

Unit Testing

Our unit tests use the shadow-cljs test-runner. To run them:

yarn test

By convention, a namespace's tests are found at a corresponding namespace of the same name with an added -test suffix. For example, tests for frontend.db.model are found in frontend.db.model-test.

There are a couple different ways to develop with tests:

Focus Tests

Tests can be selectively run on the commandline using our own test runner which provides the same test selection options as cognitect-labs/test runner. For this workflow:

  1. Run clj -M:test watch test in one shell
  2. Focus tests:
  3. Add ^:focus metadata flags to tests e.g. (deftest ^:focus test-name ...).
  4. In another shell, run node static/tests.js -i focus to only run those tests. To run all tests except those tests run node static/tests.js -e focus.
  5. Or focus namespaces: Using the regex option -r, run tests for frontend.util.page-property-test with node static/tests.js -r page-property.

Multiple options can be specified to AND selections. For example, to run all frontend.util.page-property-test tests except for the focused one: node static/tests.js -r page-property -e focus

For help on more options, run node static/tests.js -h.

Autorun Tests

To run tests automatically on file save, run clojure -M:test watch test --config-merge '{:autorun true}'. Specific namespace(s) can be auto run with the :ns-regexp option e.g. clojure -M:test watch test --config-merge '{:autorun true :ns-regexp "frontend.util.page-property-test"}'.

Database tests

To write a test that uses a datascript db:

  • Be sure your test ns has test fixtures from test-helper ns to create and destroy test databases after each test.
  • The easiest way to set up test data is to use test-helper/load-test-files.
  • For the repo argument that most fns take, pass it test-helper/test-db

Performance tests

To write a performance test:

  • Use frontend.util/with-time-number to get the time in ms.

  • Example:

    (are [x timeout] (>= timeout (:time (util/with-time-number (block/normalize-block x true))))
        ... )

For examples of these tests, see frontend.db.query-dsl-test and frontend.db.model-test.

Async Unit Testing

Async unit testing is well supported in ClojureScript. https://clojurescript.org/tools/testing#async-testing is a good guide for how to do this. We have a couple of test helpers that make testing async easier:

  • frontend.test.helper/deftest-async - deftest for async tests that ensures uncaught exceptions don't abruptly end the test suite. If you don't use this macro for async tests, you are expected to handle unexpected failures in your test
  • frontend.test.helper/with-reset - A version of with-redefs that works for async contexts

Accessibility

Please refer to our accessibility guidelines.

Logging

For logging, we use https://github.com/lambdaisland/glogi. When in development, be sure to have enabled custom formatters in the desktop app and browser. Without this enabled, most of the log messages aren't readable.

Data validation and generation

We use both spec and malli for data validation and (and generation someday). malli has the advantage that its schema is data and can be used for additional purposes. See plugin-config for an example.

Specs should go under src/main/frontend/spec/ and be compatible with clojure and clojurescript. See frontend.spec.storage for an example.

Malli schemas should go under src/main/frontend/schema/ and be compatible with clojure and clojurescript. See frontend.schema.handler.plugin-config for an example.

By following these conventions, these should also be usable by babashka. This is helpful as it allows for third party tools to be written with logseq's data model.

Development Tools

There are some babashka tasks under nbb: which are useful for inspecting database changes in realtime. See these docs for more info.