swiftlang/swift-build

Allow libclang_scanner_scan_dependencies to propagate an environment dictionary to clang

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#835 opened on Oct 2, 2025

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good first issue

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Description

libclang_scanner_scan_dependencies is invoked in-process and doesn't currently have a means to propagate an environment dictionary, so it uses the calling process's.

This impacts the explicitModulesEnvironmentTest(), which has to mutate the process environment as a workaround.

Contributor guide

Research direction
Examine the current implementation of libclang scanner scan dependencies to see how it accesses the process environment, then modify it to accept an optional environment dictionary parameter.
Tech stack
swiftccpp
Domain
build 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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
SwiftC
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45