swiftlang/swift

[SR-8706] Fix up parseDependencyFile to not crash on invalid YAML

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#51,218 opened on Sep 5, 2018

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bugcompilergood first issuelegacy driver

Description
Previous ID SR-8706
Radar rdar://problem/25095498
Original Reporter @belkadan
Type Bug
Votes 0
Component/s Compiler
Labels Bug, Driver, StarterBug
Assignee kushaj (JIRA)
Priority Medium

md5: dfcb979cb9d3bef3f8ec210cda836a79

relates to:

  • SR-8707 Write out swiftdeps files atomically

Issue Description:

LLVM's YAML parser returns null when it encounters a malformed node, but parseDependencyFile (in DependencyFile.cpp) isn't checking for this. We should fix this so that a malformed "swiftdeps" file doesn't result in crashes.

This applies to all uses of the LLVM YAML parser, really:

  • OutputFileMap::parse in OutputFileMap.cpp

  • populateOutOfDateMap in Driver.cpp

  • YamlGroupInputParser in Serialization.cpp already seems to be doing this correctly.

  • APIDiffItemStore and SILPassPipelinePlan::getPassPipelineFromFile don't really have to care about malformed input.

Tests for these APIs can go into the unittests/Driver/ folder.

Contributor guide

Tech stack
swiftcpp
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++ basicsYAML parsing fundamentals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80
Research direction
Fix parseDependencyFile in lib/Driver/DependencyFile.cpp to check for null returns from LLVM YAML parser on malformed input. Similar issues exist in OutputFileMap.cpp and Driver.cpp. Examine how Serialization.cpp handles this correctly. Add unit tests in unittests/Driver/ to verify crash prevention.