quarkusio/quarkus

Picocli extension - consider generating command metadata during build

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#16,355 opened on Apr 8, 2021

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 (22 comments) (0 reactions) (0 assignees)Java (2,464 forks)batch import
area/cligood first issuekind/enhancement

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Description

ATM picocli builds the CommandSpec metadata using reflection every time the application is started. This is OK in most situations but may represent considerable overhead for applications that finish instantly, e.g. some Quarkus CLI commands. It might make sense to analyze the commands during build and either generate some "builder" classes or record the metadata (e.g. using AnnotationProxyBuildItem) and build the metadata in a recorder method.

Contributor guide

Research direction
Investigate how the current Picocli extension uses reflection at runtime to build CommandSpec. Look at the Quarkus build system to understand how annotation processing and bytecode generation work, e.g., using AnnotationProxyBuildItem. Prototype a build time approach that generates CommandSpec metadata as builder classes or records metadata in a recorder method.
Tech stack
java
Domain
backendclibuild system
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaMaven or Gradle
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60