quarkusio/quarkus

Picocli extension - consider generating command metadata during build

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#16355 opened on Apr 8, 2021

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 (22 comments) (0 reactions) (0 assignees)Java (12,967 stars) (2,464 forks)batch import
area/cligood first issuekind/enhancement

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

Tech stack
java
Domain
cliperformancebuild system
Issue type
performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Java programmingQuarkus frameworkPicocli libraryBuild time optimization concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the current picocli extension in Quarkus (e.g., in extensions/picocli/). Look at the existing CommandSpec creation during startup. Explore the use of AnnotationProxyBuildItem for capturing metadata at build time. Review the discussion in the issue comments for alternative approaches. Consider implementing a BuildStep that generates the command metadata and stores it in a recorder.