syz-cluster: guess base patch by blob hashes from the diff

Before traversing the list of trees, attempt to determine the base
tree/commit by looking at the SHA hashes from the supplied git diffs.

4 files changed, 21 insertions, 2 deletions

diff --git a/syz-cluster/pkg/triage/commit.go b/syz-cluster/pkg/triage/commit.go
index 81c7f6150..53229e32c 100644
--- a/syz-cluster/pkg/triage/commit.go
+++ b/syz-cluster/pkg/triage/commit.go
@@ -12,8 +12,7 @@ import (
 )
 
 // TODO: Some further improvements:
-//   1. Consider the blob hashes incorporated into the git diff. These may restrict the set of base commits.
-//   2. Add support for experimental sessions: these may be way behind the current HEAD.
+//   1. Add support for experimental sessions: these may be way behind the current HEAD.
 
 type TreeOps interface {
 	HeadCommit(tree *api.Tree) (*vcs.Commit, error)
diff --git a/syz-cluster/pkg/triage/git.go b/syz-cluster/pkg/triage/git.go
index 390bd11b1..58437c913 100644
--- a/syz-cluster/pkg/triage/git.go
+++ b/syz-cluster/pkg/triage/git.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/google/syzkaller/pkg/debugtracer"
 	"github.com/google/syzkaller/pkg/vcs"
 	"github.com/google/syzkaller/syz-cluster/pkg/api"
 )
@@ -55,3 +56,7 @@ func (ops *GitTreeOps) ApplySeries(commit string, patches [][]byte) error {
 	}
 	return nil
 }
+
+func (ops *GitTreeOps) BaseForDiff(patch []byte, tracer debugtracer.DebugTracer) (*vcs.BaseCommit, error) {
+	return ops.Git.BaseForDiff(patch, tracer)
+}
diff --git a/syz-cluster/pkg/triage/tree.go b/syz-cluster/pkg/triage/tree.go
index 6cd920429..5d75c380a 100644
--- a/syz-cluster/pkg/triage/tree.go
+++ b/syz-cluster/pkg/triage/tree.go
@@ -45,3 +45,12 @@ func SelectTrees(series *api.Series, trees []*api.Tree) []*api.Tree {
 	})
 	return result
 }
+
+func TreeFromBranch(trees []*api.Tree, branch string) *api.Tree {
+	for _, tree := range trees {
+		if strings.HasPrefix(branch, tree.Name+"/") {
+			return tree
+		}
+	}
+	return nil
+}
diff --git a/syz-cluster/pkg/triage/tree_test.go b/syz-cluster/pkg/triage/tree_test.go
index 7bd9ed3ed..92d3ce014 100644
--- a/syz-cluster/pkg/triage/tree_test.go
+++ b/syz-cluster/pkg/triage/tree_test.go
@@ -74,3 +74,9 @@ func TestSelectTrees(t *testing.T) {
 		})
 	}
 }
+
+func TestTreeFromBranch(t *testing.T) {
+	treeA, treeB := &api.Tree{Name: "a"}, &api.Tree{Name: "b"}
+	assert.Equal(t, treeA, TreeFromBranch([]*api.Tree{treeA, treeB}, "a/some_branch"))
+	assert.Equal(t, treeB, TreeFromBranch([]*api.Tree{treeA, treeB}, "b/some_branch"))
+}