if !h.Available() {
		return nil, ServerNotInstalledError{name: "git"}
	}

	baseEnv := append(slices.Clip(env),
		"GIT_PROJECT_ROOT="+dir,
		"GIT_HTTP_EXPORT_ALL=1",
	)

	handler := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		// The Git client sends the requested Git protocol version as a
		// "Git-Protocol" HTTP request header, which the CGI host then converts
		// to an environment variable (HTTP_GIT_PROTOCOL).

 */

package org.gradle.performance.util

import org.gradle.util.internal.DefaultGradleVersion

class Git {
    static final Git INSTANCE = new Git()
    final String commitId
    final String branchName

    static Git current() {
        return INSTANCE
    }

    private Git() {
        commitId = System.getProperty("gradleBuildCommitId", DefaultGradleVersion.current().gitRevision)

	// The "--is-ancestor" flag was added to "git merge-base" in version 1.8.0, so
	// this won't work with Git 1.7.1. According to golang.org/issue/28550, cmd/go
	// already doesn't work with Git 1.7.1, so at least it's not a regression.
	//
	// git merge-base --is-ancestor exits with status 0 if rev is an ancestor, or
	// 1 if not.
	_, err := Run(ctx, r.dir, "git", "merge-base", "--is-ancestor", "--", tag, rev)

! go mod download -json vcs-test.golang.org/git/hello.git@latest vcs-test.golang.org/git/hello.git/v9@latest vcs-test.golang.org/git/hello.git/sub/v9@latest vcs-test.golang.org/git/tagtests.git@latest vcs-test.golang.org/git/tagtests.git@v0.2.2 vcs-test.golang.org/git/tagtests.git@master
cp stdout all.json

# clean the module cache, make sure that makes go mod download re-run git fetch, clean again
go clean -modcache

[short] skip 'generates a vcstest git repo'
[!git] skip

mkdir $WORK/mod1
mkdir $WORK/mod2
env GONOSUMDB=vcs-test.golang.org

env GOPROXY=direct
env GOMODCACHE=$WORK/mod1


# If we query a module version from a git repo, we expect its
# Origin data to be reusable.

go list -m -json vcs-test.golang.org/git/issue61415.git@latest
cp stdout git-latest.json
stdout '"Version": "v0.0.0-20231114180001-f213069baa68"'
stdout '"Origin":'

# go mod download has an error 'v1.x.y is not a tag'
# with go1.16.14: 
# `go1.16.14 list -m vcs-test.golang.org/git/gitrepo1.git@v1.2.3`
# will output with error:
# go list -m: vcs-test.golang.org/git/gitrepo1.git@v1.2.3: invalid version: unknown revision v1.2.3
# See golang/go#51312.
go list -m vcs-test.golang.org/git/gitrepo1.git@v1.2.3
stdout 'vcs-test.golang.org/git/gitrepo1.git v1.2.3'

handle git

env GIT_AUTHOR_NAME='Bryan C. Mills'
env GIT_AUTHOR_EMAIL='******@****.***'
env GIT_COMMITTER_NAME=$GIT_AUTHOR_NAME
env GIT_COMMITTER_EMAIL=$GIT_AUTHOR_EMAIL

at 2023-11-14T13:00:00-05:00

git init

git add go.mod nested
git commit -m 'nested: add go.mod'
git branch -m main

git tag has-nested

at 2023-11-14T13:00:01-05:00

git rm -r nested
git commit -m 'nested: delete subdirectory'

[short] skip 'generates a vcstest git repo'
[!git] skip

env GOPROXY=direct

# Control case: fetching a nested module at a tag that exists should
# emit Origin metadata for that tag and commit, and the origin should
# be reusable for that tag.

go list -json -m --versions -e vcs-test.golang.org/git/issue61415.git/nested@has-nested
cp stdout has-nested.json
stdout '"Origin":'
stdout '"VCS": "git"'

exec git commit -m 'initial commit'

env GIT_COMMITTER_DATE=2024-01-30T10:53:00+08:00
env GIT_AUTHOR_DATE=2024-01-30T10:53:00+08:00
exec git add extra.go
exec git commit -m 'add extra.go'

# Assume the tree object from initial commit is not available (e.g. partial clone)
exec git log --pretty=%T
cmp stdout $WORK/.git-trees

rm .git/objects/66/400c89b45cc96da36d232844dbf9ea5daa6bcf

# Build the module, which should succeed

        } finally {
            if (git != null) {
                git.close();
            }
        }
    }

    private static void resetRepo(File workingDir, GitVersionControlSpec gitSpec, VersionRef ref) {
        Git git = null;
        try {
            git = Git.open(workingDir);
            git.reset().setMode(ResetCommand.ResetType.HARD).setRef(ref.getCanonicalId()).call();