Git config setting `safe.bareRepository=explicit` can break dependency resolution

[valentary]

Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

A recent software update from Sourcetree added or modified the safe.bareRepository=explicit configuration option to git.

This interfers with the package resolution, it seems to only involve our private packages on github.

The packages refuse to resolve and we get error like saying it cannot fetch revision (see below)

Expected behavior

% swift package resolve
Fetching git@github.com:<MyOrg>/<MyDependencyPackage>.git
Fetched git@github.com:<MyOrg>/<MyDependencyPackage>.git from cache (5.32s)
Creating working copy for git@github.com:<MyOrg>/<MyDependencyPackage>.git
Working copy of git@github.com:<MyOrg>/<MyDependencyPackage>.git resolved at <BranchName> (f96e2ec)

Actual behavior

% swift package resolve
Fetching git@github.com:<MyOrg>/<MyDependencyPackage>.git
Fetched git@github.com:<MyOrg>/<MyDependencyPackage>.git from cache (5.32s)
error: Couldn’t get revision ‘<A Commit Hash>^{commit}’:
    fatal: cannot use bare repository '/Users/<myuserdir>/Repos/Fixes/<MyPackage>/.build/repositories/<MyDependencyPackage>-ad20a496' (safe.bareRepository is 'explicit') in git@github.com:<MyOrg>/<MyDependencyPackage>.git

Steps to reproduce

A Package with a dependency to a private github repo
In the CLI

1. git config --global --replace safe.bareRepository explicit
2. swift package resolve

Swift Package Manager version/commit hash

Swift Package Manager - Swift 6.0.0-dev

Swift & OS version (output of swift --version ; uname -a)

swift-driver version: 1.115 Apple Swift version 6.0 (swiftlang-6.0.0.9.10 clang-1600.0.26.2)
Target: arm64-apple-macosx15.0
Darwin rlee-MacBook-Pro 24.0.0 Darwin Kernel Version 24.0.0: Tue Sep 24 23:37:36 PDT 2024; root:xnu-11215.1.12~1/RELEASE_ARM64_T6020 arm64

[valentary]

It seems it was an update in sourcetree that caused the issue : https://jira.atlassian.com/browse/SRCTREEWIN-14483

[valentary]

But it's also default behaviour now in git : git/git@e35f202

[paiv]

safe.bareRepository=explicit is hardening Git security. SPM should follow Git's guideline "by specifying GIT_DIR or --git-dir".

Sourcetree was eager to deliver this update, but is not the cause of the issue.

[Kyle-Ye]

safe.bareRepository=explicit is hardening Git security. SPM should follow Git's guideline "by specifying GIT_DIR or --git-dir".

Sourcetree was eager to deliver this update, but is not the cause of the issue.

+1.

1. We should support the config in SwiftPM in a near future version of the toolchain.
2. But also I believe Sourcetree should not globally add the config on the user's behalf.

[valentary]

2. But also I believe Sourcetree should not globally add the config on the user's behalf.

That may be true, it was unexpected and it did cause quite some confusion for us to track down the cause. But it looks like this will roll out by default in future versions of git.

[Kyle-Ye]

But it's also default behaviour now in git : git/git@e35f202

No. Git added safe.bareRepository=explicit as an opt-in feature since 2.38.0. But I have not seen any indiction that Git is going to make it as the default behavior.