fix(witness): witness should not error on an empty git repo with no c…

…ommits

Fixes in-toto#121

go.work.sum

@@ -232,6 +232,7 @@ github.com/stoewer/go-strcase v1.2.0/go.mod h1:IBiWB2sKIp3wVVQ3Y035++gc+knqhUQag
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.7.1-0.20210427113832-6241f9ab9942/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/testifysec/go-witness v0.1.13/go.mod h1:nyEU+h1Pma91QABbSzDDikIhGfU4YjN7d+S7Cdn/w20=
+github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/vektah/gqlparser/v2 v2.4.3-0.20220508162109-d3d9eb001575/go.mod h1:flJWIR04IMQPGz+BXLrORkrARBxv/rtyIAFvd/MceW0=
 github.com/vmihailenco/msgpack v3.3.3+incompatible h1:wapg9xDUZDzGCNFlwc5SqI1rvcciqcxEHac4CYj89xI=
 github.com/vmihailenco/msgpack v3.3.3+incompatible/go.mod h1:fy3FlTQTDXWkZ7Bh6AcGMlsjHatGryHQYUTf1ShIgkk=
@@ -300,6 +301,7 @@ golang.org/x/term v0.10.0 h1:3R7pNqamzBraeqj/Tj8qt1aQ2HpmlC+Cx/qL/7hn4/c=
 golang.org/x/term v0.10.0/go.mod h1:lpqdcUyK/oCiQxvxVrppt5ggO2KCZ5QblwqPnfZ6d5o=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.6.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/time v0.2.0 h1:52I/1L54xyEQAYdtcSuxtiT84KGYTBGXwayxmIpNJhE=
 golang.org/x/tools v0.0.0-20200522201501-cb1345f3a375/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20200717024301-6ddee64345a6/go.mod h1:njjCfa9FT2d7l9Bc6FUM5FLjQPp3cFF28FI3qnDFljA=
 golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=

subtrees/go-witness/attestation/git/git.go

@@ -17,6 +17,7 @@ package git
 import (
 	"crypto"
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/go-git/go-git/v5"
@@ -106,6 +107,9 @@ func (a *Attestor) Attest(ctx *attestation.AttestationContext) error {
 
 	head, err := repo.Head()
 	if err != nil {
+		if strings.Contains(err.Error(), "reference not found") {
+			return nil
+		}
 		return err
 	}
 

subtrees/go-witness/attestation/git/git_test.go

@@ -43,10 +43,10 @@ func TestNameTypeRunType(t *testing.T) {
 	require.Equal(t, RunType, attestor.RunType(), "Expected the attestor's run type")
 }
 
-func TestRun(t *testing.T) {
+func TestRunWorksWithCommits(t *testing.T) {
 	attestor := New()
 
-	_, dir, cleanup := createTestRepo(t)
+	_, dir, cleanup := createTestRepo(t, true)
 	defer cleanup()
 
 	ctx, err := attestation.NewContext([]attestation.Attestor{attestor}, attestation.WithWorkingDir(dir))
@@ -140,7 +140,23 @@ func TestRun(t *testing.T) {
 
 }
 
-func createTestRepo(t *testing.T) (*git.Repository, string, func()) {
+func TestRunWorksWithoutCommits(t *testing.T) {
+	attestor := New()
+
+	_, dir, cleanup := createTestRepo(t, false)
+	defer cleanup()
+
+	ctx, err := attestation.NewContext([]attestation.Attestor{attestor}, attestation.WithWorkingDir(dir))
+	require.NoError(t, err, "Expected no error from NewContext")
+
+	err = ctx.RunAttestors()
+	require.NoError(t, err, "Expected no error from RunAttestors")
+
+	require.Empty(t, attestor.ParentHashes, "Expected the parent hashes to be set")
+}
+
+// Creates an ephemeral repo for your testing
+func createTestRepo(t *testing.T, withCommit bool) (*git.Repository, string, func()) {
 	// Create a temporary directory for the test repository
 	tmpDir, err := os.MkdirTemp("", "test-repo")
 	require.NoError(t, err)
@@ -149,7 +165,21 @@ func createTestRepo(t *testing.T) (*git.Repository, string, func()) {
 	repo, err := git.PlainInit(tmpDir, false)
 	require.NoError(t, err)
 
-	// Create a new file in the repository
+	if withCommit {
+		addCommit(tmpDir, t, repo)
+	}
+
+	// Return the test repository, the path to the test repository, and a cleanup function
+	return repo, tmpDir, func() {
+		err := os.RemoveAll(tmpDir)
+		require.NoError(t, err)
+	}
+}
+
+// Create a new file in the repository
+// Add the new file to the repository
+// Commit the new file to the repository
+func addCommit(tmpDir string, t *testing.T, repo *git.Repository) {
 	filePath := filepath.Join(tmpDir, "test.txt")
 	file, err := os.Create(filePath)
 	require.NoError(t, err)
@@ -158,13 +188,11 @@ func createTestRepo(t *testing.T) (*git.Repository, string, func()) {
 	err = file.Close()
 	require.NoError(t, err)
 
-	// Add the new file to the repository
 	worktree, err := repo.Worktree()
 	require.NoError(t, err)
 	_, err = worktree.Add("test.txt")
 	require.NoError(t, err)
 
-	// Commit the new file to the repository
 	_, err = worktree.Commit("Initial commit", &git.CommitOptions{
 		Author: &object.Signature{
 			Name:  "Test User",
@@ -173,12 +201,6 @@ func createTestRepo(t *testing.T) (*git.Repository, string, func()) {
 		},
 	})
 	require.NoError(t, err)
-
-	// Return the test repository, the path to the test repository, and a cleanup function
-	return repo, tmpDir, func() {
-		err := os.RemoveAll(tmpDir)
-		require.NoError(t, err)
-	}
 }
 func createTestCommit(t *testing.T, repoPath string, message string) {
 	// Open the Git repository

subtrees/witness/docs/attestors/git.md

@@ -1,8 +1,10 @@
 # Git Attestor
 
 The Git Attestor records the current state of the objects in the git repository, including untracked objects.
+
 Both staged and unstaged states are recorded.
 
+The Git Attestor assumes you are working from a git repository that has been initialized and has commits.
 
 ## Subjects