haskell-servant/servant

Generic records causes very slow compile times

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#1,038 创建于 2018年9月18日

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 (6 评论) (0 反应) (0 负责人)Haskell (1,953 star) (422 fork)batch import
help wantedperformance

描述

apparently, large APIs using the Servant.API.Generic record mechanism are orders of magnitude slower to compile than their :<|> equivalent

https://twitter.com/mattoflambda/status/1041622124576661504

I'm not sure how much we can do about this, but we could at least benchmark, create a minimal example that triggers this behaviour, and submit it to GHC as a bug

贡献者指南

技术栈
无
领域
backendperformance
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
5
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-2 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
mostly clear
前置要求
Haskell knowledgeServant library familiarityGHC compiler internals
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
10
研究方向
The issue describes slow compile times when using Servant.API.Generic record mechanism compared to :<|> style. To address this, first create a benchmark that reproduces the performance difference using a minimal example. Then analyze the generated Core or GHC's output to identify the cause. If the issue lies in GHC, submit a bug report to the GHC tracker. Relevant files include the Servant.Generic module.