commercialhaskell/stack

--file-watch and --exec with running server like command does not build again

Open

#4,153 创建于 2018年7月13日

在 GitHub 查看
 (6 评论) (9 反应) (0 负责人)Haskell (4,060 star) (848 fork)batch import
awaiting pull requestcomponent: buildhelp wantedtype: enhancement

描述

General summary

If you run any command via the --exec flag which does not exit (like a server), then --file-watch does not build again if the files changes.

I can understand why that is, and it is probably how the implementation is - but it is counter-intuitive. Other dev tools (like gunicorn, go's reflex) works as expected. If a file changes, even with server like commands, it rebuilds/reloads and runs the commands again.

Steps to reproduce

stack build --fast --exec "sleep infinity" --file-watch
  1. Change a file in the same project

Expected

The build happens again, and the exec command is run again.

Actual

Nothing happens. (Because the exec command never exited)

Stack version

$ stack --version
Version 1.7.1, Git revision 681c800873816c022739ca7ed14755e85a579565 (5807 commits) x86_64 hpack-0.28.2

Method of installation

  • Official binary, downloaded from stackage.org or fpcomplete's package repository

PS: There is an issue #2955 . But that is different than this issue.

贡献者指南

技术栈
无
领域
build system
议题类型
feature
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。
3
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。
half day
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。
clear
前置要求
basic file watching conceptsunderstanding of process management
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。
20
研究方向
The issue is about stack's file watch behavior when exec command doesn't exit. Look at the file watch implementation in stack's source code, particularly the part that waits for the exec command to finish before re building. Consider modifying the logic to kill and restart the background process on file changes. Also investigate issue #2955 for related context.