tinker-dev

name	tinker-dev
description	Development guidance for the Apache TinkerPop monorepo. Use when building, testing, or contributing to TinkerPop's graph computing framework and its multi-language Gremlin ecosystem (Java, Python, JavaScript, .NET, Go). Covers coding conventions, build recipes, test evaluation, documentation, development environment setup, and Gremlin MCP server usage.
license	Apache-2.0
compatibility	Requires Java 11+, Maven 3.5.3+, Docker. Individual GLVs may need Python, Node.js, .NET SDK, or Go.
metadata	{"version":"1.0.0","project":"Apache TinkerPop"}

TinkerPop Development Skill

Project Overview

Apache TinkerPop is a graph computing framework providing a standard API (the Gremlin graph traversal language) for graph databases and processors. The repository is a Maven multi-module monorepo that wraps JVM code, Python, JavaScript/TypeScript, .NET, and Go under a single build.

Canonical project documentation (prefer local files over external URLs):

• README.md and CONTRIBUTING.md at the repo root
• Reference docs: docs/src/reference/
• Developer docs: docs/src/dev/developer/
• Provider docs and Gremlin Semantics: docs/src/dev/provider/
• IO and Serialization: docs/src/dev/io/
• Recipes: docs/src/recipes/
• Upgrade docs: docs/src/upgrade/
• Future plans: docs/src/dev/future/

Definition of Done

A change is not done until a full Maven validation has passed locally. Run it before presenting work for review — even when your targeted or unit tests already pass, and even if you judge a full run unnecessary. Incremental testing during development is encouraged, but it does not satisfy this gate.

Validation is two steps. First, rebuild and install the whole reactor so every module picks up your changes:

mvn clean install -DskipTests

Then run verify scoped to what you changed, using the broadest rule that applies, and always list every module you touched.

Self-contained modules — changing one of these only requires validating that module:

Changed module	Validate command
Python GLV	mvn verify -pl gremlin-python
JavaScript GLV	mvn verify -pl :gremlin-javascript
.NET GLV	mvn verify -pl :gremlin-dotnet,:gremlin-dotnet-source,:gremlin-dotnet-tests
Go GLV	mvn verify -pl :gremlin-go
gremlint	mvn verify -pl :gremlint
gremlin-mcp	mvn verify -pl :gremlin-mcp
Other single JVM module (e.g. tinkergraph-gremlin, gremlin-console)	mvn verify -pl <module> -DskipIntegrationTests=false

Shared modules — depended on by others, so changing them means validating the consumers too. Use the broadest rule that matches:

• gremlin-server, gremlin-driver, or gremlin-util define the wire protocol and serialization that every GLV exercises → validate the changed module(s) plus all GLVs: mvn verify -pl <changed>,gremlin-python,:gremlin-javascript,:gremlin-dotnet,:gremlin-dotnet-source,:gremlin-dotnet-tests,:gremlin-go -DskipIntegrationTests=false
• gremlin-core, gremlin-test, or anything they depend on ripple across the whole project, including the OLAP engines (hadoop-gremlin, spark-gremlin) → run everything: mvn clean install -DskipIntegrationTests=false
• Unsure? Treat it as the gremlin-core case and run everything.

Docs or code comments only — no validation gate; this gate is for changes that affect behavior.

Things that quietly invalidate a run

• GLV tests are skipped unless activated. A GLV is built and tested only when its .glv sentinel exists: gremlin-python/.glv, gremlin-go/.glv, and both gremlin-dotnet/src/.glv and gremlin-dotnet/test/.glv (JavaScript builds by default). Without the sentinel the module is silently skipped — a green run may have tested nothing of your change. Create the sentinel (or pass -Pglv-python / -Pglv-go) before validating a GLV change.
• Grammar and feature-test changes need a reactor build to take effect. The ANTLR grammar (gremlin-language/src/main/antlr4/Gremlin.g4) and the Gherkin features under gremlin-test drive code generation during mvn clean install — ANTLR parsers, and per-language test code generated from the feature corpus (e.g. gremlin-python/build/generate.groovy, with equivalents for Go, .NET, and JavaScript). After changing either, run mvn clean install -DskipTests before relying on any test, including fast native ones, or you will be testing stale generated code.
• Judge pass/fail by the Maven exit code, not console text. Do not grep/tail the build output — tests deliberately emit expected errors, so the log misleads. Exit 0 = pass. For Python, detailed per-suite results are in gremlin-python/target/python3/python-reports/*.xml.

If you cannot run the validation (for example, Docker is unavailable), say so explicitly and report the change as not validated — do not present it as done.

Repository Structure

Most module names map directly to their purpose (gremlin-core, gremlin-server, gremlin-go, etc.). Two things that aren't obvious:

• The JavaScript workspace lives under gremlin-js/ — it contains gremlin-javascript/ (the gremlin npm driver), gremlin-mcp/, and gremlint/. There is no top-level gremlin-javascript/ directory.
• Maven orchestrates the build for every module, including the non-JVM ones (Python, JavaScript, .NET, Go) — which is why the validation in the Definition of Done runs through Maven rather than each language's native test runner.

Cross-language Gherkin feature tests live in gremlin-test/.

Basic Build Commands

Build everything:

mvn clean install

Build a specific module:

mvn clean install -pl <module-name>

For GLV-specific builds and the validation commands per module, see the Definition of Done table above. For environment setup and GLV activation, see references/dev-environment-setup.md.

Conventions

The general Do/Don't rules and "when in doubt" guidance live in the root AGENTS.md — the single source of truth, not repeated here. The conventions below are the TinkerPop-specific ones that are easy to miss:

• License header: every new file needs the ASF header. Canonical text: bin/asf-license-header.txt.
• Test naming: a test using a GraphProvider with AbstractGremlinTest is suffixed Check, not Test.
• Gremlin language tests: cross-language behavior is tested with Gherkin features under gremlin-test/src/main/resources/org/apache/tinkerpop/gremlin/test/features/ (see docs/src/dev/developer/for-committers.asciidoc).
• Docs are AsciiDoc under docs/src/ — never Markdown in the main docs tree. For writing or revising any documentation (voice, per-book style, executable code blocks, AsciiDoc wiring), use the tinker-doc skill. The mechanical minimum: add new content to the right book and update its index.asciidoc.
• Changelog: for user-visible or API changes, add a concise CHANGELOG.asciidoc entry in the correct version section. Do not invent version numbers or release names. See the tinker-doc skill for changelog discipline (one entry per user-facing change, not per commit) and voice.

Otherwise, match the existing code in neighboring files — explicit imports (no wildcards), final where practical, SLF4J logging over println, Hamcrest matchers, and closing any Graph you construct in a test.

Reference Guides

Build and validate commands live in the Definition of Done table above. For the remaining task-specific guidance, see:

• Development Environment Setup — fresh clone to working environment, prerequisites, GLV activation
• Gremlin MCP Server — translation, formatting, querying via MCP