Review Groovy Migration

datadog/review-groovy-migration

> Post-migration quality review. Checks Java test files produced by migrate-groovy-to-java against the shared quality rules. Use after migration, or on any branch with recently migrated .java test files. Produces structured FINDING blocks grouped by severity, then offers to auto-fix BLOCKERs and WARNINGs.

1k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

727

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/DataDog/dd-trace-java --skill review-groovy-migration

What it tells the agent to use

found in the instruction text

Grep reads your files

The instruction itself

6 sections, as written by the author

Review migrated Java test files against the quality rules.

Step 1 — Load rules

Read .claude/skills/migrate-groovy-to-java/QUALITY_RULES.md in full before proceeding.

Step 2 — Identify target files

If the user specified files or a module path, use those. Otherwise, find files added on the current branch:

MERGE_BASE=$(git merge-base HEAD origin/master 2>/dev/null || git merge-base HEAD master)
git diff "$MERGE_BASE" --name-only --diff-filter=A | grep 'src/test/java.*\.java$'

If no files are found, fall back to modified test files:

git diff "$MERGE_BASE" --name-only | grep 'src/test/java.*\.java$'

Step 3 — Run grep-based detection

For each rule with a grep Detection pattern, run it over the target files. Use the patterns from the rules file. The patterns below assume GNU/ugrep-compatible regex (\b, \.); alternation uses grep -E "...|..." so it also works under BSD grep — adapt if your grep differs.

# RULE-C01  (also fires on RULE-C02 lines — see dedup note below)
grep -rn "assertTrue(.*instanceof" <files>

# RULE-C02  (more specific than C01)
grep -rEn "assertTrue\(.*== *null.*instanceof|assertTrue\(.*instanceof.*== *null" <files>

# RULE-F01  (BLOCKER, but verify context — see note below)
# Run as three separate greps: word boundaries (\b) combined with | alternation
# misbehave under some grep builds, so do not merge these into one alternation.
grep -rEn "\bint\b.*[Ss]ampling[Pp]riority" <files>
grep -rEn "\bint\b.*\bpriority\b" <files>
grep -rEn "\bint\b.*\bmechanism\b" <files>

# RULE-A02
grep -rn '@WithConfig(key = "' <files>

# RULE-B01
grep -rn "new LinkedHashMap<>()" <files>

# RULE-C04
grep -rn "\.getTags()\.get(" <files>

# RULE-C05  (BLOCKER, but verify context — see note below)
# A matcher is only legitimate for genuinely non-deterministic values; otherwise it
# silently relaxes an assertion the Groovy original pinned. Cross-check the Groovy source.
grep -rEn "any\(\)|anyInt\(\)|anyLong\(\)|anyString\(\)|anyByte\(\)|anyBoolean\(\)|atLeastOnce\(\)" <files>

# RULE-D01
grep -rn "mock(.*Map.*\.class)" <files>

# RULE-G01
grep -rn "/\* [a-z]" <files>

# RULE-G02
grep -rEn "\(\) -> [a-zA-Z]+\.[a-zA-Z]+\(\)" <files>

# RULE-G05  (verify context — only when close() is the finally's sole statement and there
# is no surrounding logic requiring an explicit close; read the block before flagging)
grep -rEn "\} finally \{" <files>

# RULE-H01
grep -rEn "'18446744073709551[0-9]+'" <files>

# RULE-J02
grep -rEn "CarrierVisitor|forEachKeyValue" <files>

Read the full content of any file that has at least one hit, to understand the context.

Step 4 — Structural detection (LLM-based)

For rules without grep patterns (RULE-A01, RULE-B02, RULE-B03, RULE-C03, RULE-E01, RULE-E02, RULE-E03, RULE-G04, RULE-H02, RULE-I01, RULE-I02), read all target files and identify violations based on the Before/After examples in the rules.

Step 5 — Emit structured findings

For each issue found, emit one finding block:

FINDING
  file:     <absolute path>
  line:     <line number, or range start-end>
  rule:     <RULE-XNN>
  severity: <BLOCKER|WARNING|STYLE>
  excerpt:  <the offending code, single line>
  fix:      <the corrected code, single line or brief description>

Group all findings by severity: BLOCKERs first, then WARNINGs, then STYLEs.

At the end, print a one-line summary:

Summary: N blocker(s), M warning(s), K style issue(s) across F file(s).

If no issues are found:

No findings. All rules pass.

Step 6 — Offer to fix

After the summary, ask: "Fix all BLOCKERs and WARNINGs automatically? (yes / no / select rules)"

If the user agrees:

Apply each fix. For each file changed, run ./gradlew spotlessApply on its module after editing.
Re-run the grep checks to confirm the findings are resolved.
Report which findings were fixed and which (if any) require manual attention.

How to use it

Copy the folder

Take datadog/review-groovy-migration from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.