Browse Learn Clojure Foundations as a Java Developer

Review Clojure Changes with Git

Use pull requests, small commits, CI commands, and Clojure-aware review checklists to keep team changes understandable when Java developers adopt Clojure.

Good Clojure collaboration is not just “open a pull request.” It is making small, reviewable changes to namespaces, data shapes, tests, and build commands so teammates can understand the behavior without replaying your whole REPL session.

Java engineers already know code review. The adjustment is knowing what Clojure changes tend to hide.

Review surface What can hide there
Namespace form New dependency direction, circular require risk, broad :refer :all, or unused aliases.
Data shape Changed map keys, nested structures, optional fields, or defaults.
Pure functions Behavior can shift without a class or interface changing.
Tests Expectations may be too example-specific or may miss edge cases.
Build files Classpath, REPL, test, and production commands can diverge.

Keep Pull Requests Small

A good first Clojure pull request should usually do one of these:

  • Add or revise one namespace and its tests.
  • Introduce a narrow Java/Clojure adapter.
  • Change one data shape with tests and migration notes.
  • Add one build, REPL, or test command with documentation.
  • Refactor one pipeline while preserving observable behavior.

Avoid combining formatting, dependency upgrades, namespace reshuffling, feature logic, and packaging changes in one pull request. Those changes stress different reviewers and create noisy diffs.

Write Clojure-Aware PR Descriptions

Use a description that answers the questions reviewers will actually have.

PR field Useful content
Behavior changed What the code now does differently.
Data shape New or removed keys, nested maps, defaults, and nil behavior.
Namespace impact New dependencies, renamed namespaces, or interop boundaries.
Test command Exact command run locally and expected CI command.
Review focus What needs careful review: correctness, API shape, performance, migration, or build wiring.

This is especially helpful for Java teammates who can read Clojure syntax but do not yet know where subtle changes usually live.

Review the Right Things

When reviewing Clojure, do not stop at “the functions are short.” Short code can still hide coupling, unclear data contracts, or weak test coverage.

Question Why it matters
Is the namespace dependency direction clear? Prevents reload problems and circular requires.
Are data contracts obvious at boundaries? Java callers and Clojure internals need stable shapes.
Are errors represented consistently? Mixed Java/Clojure systems often drift between exceptions and data errors.
Do tests cover behavior, not implementation trivia? Pure functions are easy to test well, but also easy to under-test.
Does CI run the same command documented in the PR? Prevents “works only in my REPL” merges.

Resolve Conflicts in Clojure Files

Merge conflicts in Clojure often happen in ns forms, data literals, and test expectations. Resolve the meaning first, then the parentheses.

1--- current branch
2  (:require [order-service.pricing :as pricing]
3            [order-service.validation :as validation]))
4--- incoming feature/audit
5  (:require [order-service.pricing :as price]
6            [order-service.audit :as audit]))

A good resolution may not be either side exactly:

1(ns order-service.handler
2  (:require
3   [order-service.audit :as audit]
4   [order-service.pricing :as pricing]
5   [order-service.validation :as validation]))

After resolving a conflict, run tests. If the conflict touched namespace dependencies, also reload the affected namespace from a clean REPL or run the project command that CI uses.

Collaboration Checklist

Before requesting review:

  1. Rebase or merge from the team baseline according to project policy.
  2. Run the documented test command.
  3. Inspect git diff origin/main...HEAD.
  4. Remove generated files from the commit.
  5. Explain data-shape, namespace, and build-tool changes in the PR description.

Before approving:

  1. Read the ns form and dependency direction.
  2. Check source and test changes together.
  3. Confirm the PR documents runnable commands.
  4. Look for hidden Java/Clojure boundary coupling.
  5. Ask for smaller commits if unrelated changes are bundled.

Knowledge Check

### What is a Clojure-specific review risk in a small-looking pull request? - [x] A small `ns` or data-shape change can alter dependency direction or behavior broadly - [ ] Short functions cannot contain bugs - [ ] Pull requests cannot include tests - [ ] Git cannot show Clojure diffs > **Explanation:** Clojure diffs can be compact but semantically important. Review namespace dependencies and data contracts carefully. ### What should a useful Clojure PR description include? - [x] Behavior changed, data-shape impact, namespace impact, and test command - [ ] Only the branch name - [ ] Only a screenshot of the REPL - [ ] A list of every parenthesis in the diff > **Explanation:** Reviewers need reproducible behavior and boundary context, not just a generic summary. ### After resolving a conflict in an `ns` form, what should you do? - [x] Run tests and verify the affected namespace loads cleanly - [ ] Delete the namespace - [ ] Commit without checking because syntax highlighting passed - [ ] Remove all aliases > **Explanation:** Namespace conflicts can leave dependency direction or loading broken even when the file looks syntactically balanced.
Revised on Saturday, May 23, 2026