swiftlang/swift

[SR-1266] Fix duplication of @VARIABLES@ in test and validation-test lit.site.cfg.in

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#43,874 opened on Apr 19, 2016

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bugcmakegood first issue

Description
Previous ID SR-1266
Radar None
Original Reporter @modocache
Type Bug
Votes 0
Component/s Project Infrastructure
Labels Bug, CMake, StarterBug
Assignee None
Priority Medium

md5: 415295060b366f5b63750d3f4a872cf4

Issue Description:

The test and validation-test directories in the Swift project define tests and validation tests. The lit testing tool is used to run the tests. lit allows test suites to be configured via a file named lit.cfg.

Both test/lit.cfg and validation-test/lit.cfg use parameters that are defined as part of the Swift CMake build scripts. The CMake portion of the build system is aware of a lot of information that is useful to the tests, such as the location where LLVM build products will be placed--something like /path/to/build/llvm-macosx-x86_64/bin. CMake communicates these values to lit via the files test/lit.site.cfg.in and validation-test/lit.site.cfg.in. You can see the exact lines that CMake find-and-replaces variables like @LLVM_BINARY_DIR@ here.

I was recently bit by this system: I had added a new variable, @SWIFT_ANDROID_NDK_PATH@, to test/lit.site.cfg.in, but not to validation-test/lit.site.cfg.in. I was confused why my tests failed to be configured with the correct path sometimes.

It would be nice if I only had to add variables like @SWIFT_ANDROID_NDK_PATH@ to a single file, as opposed to several.

Accomplishing this requires basic knowledge of how the Swift test suite is run, as well some CMake and Python syntax. This task is a good opportunity to learn more about the Swift build system, its test suite, CMake, and lit.

Contributor guide

Tech stack
swiftpython
Domain
build systemtestingdeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
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 CMakePython basicsSwift build system
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Examine test/CMakeLists.txt lines 173-186 to understand how CMake substitutes variables. Compare test/lit.site.cfg.in and validation test/lit.site.cfg.in to identify duplication. Consider creating a common lit.site.cfg.in template or modifying CMake to generate both files from a single source. Look at the referenced PR #1714 for context.