commercialhaskell/stack

--exec --file-watch combo not working as expected

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#2,955 opened on Jan 27, 2017

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 (5 comments) (1 reaction) (0 assignees)Haskell (4,060 stars) (848 forks)batch import
component: Windowsfurther investigation requiredhelp wantedtype: bug

Description

Steps to reproduce

Choose a repo and run:

stack build --exec "echo run me, please!" --file-watch

The echo doesn't echo yet. Type 'help'. The executable then runs eg

stack build --exec "echo run me, please!" --file-watch

help
run me, please!

help: display this help
quit: exit
build: force a rebuild
watched: display watched files
ExitSuccess
Type help for available commands. Press enter to force a rebuild.
quit

Associated with this, build does not seem to force a build.

Expected

I expected the executable to run initially,, before kicking the file-watch cycle in the guts.

Actual

the --exec runs after typing help

version

$ stack --version
Version 1.3.2 x86_64 hpack-0.15.0

Contributor guide

Tech stack
None
Domain
clibuild system
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
None
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the interaction between exec and file watch flags in the Stack build system. Start by looking at the command line parsing and the main build loop, likely in src/Stack/Build.hs or similar. Understand why the exec command runs only after a user input instead of at the start. The issue may be in the order of initialization of the file watch listener and the execution of the command.