swiftlang/swift-package-manager

[SR-7982] Swift build forces recompilation with Makefile

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#5353 opened on Jun 12, 2018

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 (19 comments) (0 reactions) (1 assignee)Swift (10,145 stars) (1,462 forks)batch import
buggood first issue

Description
Previous ID SR-7982
Radar rdar://problem/37440217
Original Reporter andreasw (JIRA User)
Type Bug

Ubuntu 18.04, Swift 4.2 dev.
Votes 0
Component/s Compiler, Package Manager
Labels Bug, Driver, StarterBug
Assignee None
Priority Medium

md5: b246f9ef9446cfcc35be81e5733a0227

Issue Description:

I have a simple Makefile for building:

build:

    swift build

After typing "make" the expected happens, the swift file is compiled.

After a second "make" the expected happens again, nothing is compiled.

Opening vim and typing ":make" I expected that nothing happens but the file is recompiled.

After a second ":make" in vim this time the expected happens again and nothing is compiled.

But if you close vim and type "make" again, the file has to be compiled again.

Contributor guide

Tech stack
swift
Domain
build systemdeveloper experience
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.
1-2 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
Basic Swift knowledgeFamiliarity with MakefileUnderstanding of build systems
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the difference in behavior when running `swift build` directly vs. via vim's `:make`. The issue suggests that the build system's incremental compilation detection fails when the command is executed through vim. Check if environment variables (e.g., `TERM`, `VIM`) or file system events differ. Look into the Swift Package Manager's build logic in the `lib/Build` directory and the driver's file change detection. Review the 19 comments for any additional clues or partial solutions. Ensure the fix works consistently across different shell environments.