pkg/aflow/flow/patching: use recent commit subjects

Give LLM the recent commit subjects when it generates description,
so that it can use the same style.

Add infrastrcuture to write end-to-end action tests to test it.

3 files changed, 98 insertions, 0 deletions

diff --git a/pkg/aflow/flow/patching/actions.go b/pkg/aflow/flow/patching/actions.go
index 2c98e9306..d42c24fa1 100644
--- a/pkg/aflow/flow/patching/actions.go
+++ b/pkg/aflow/flow/patching/actions.go
@@ -4,6 +4,8 @@
 package patching
 
 import (
+	"errors"
+	"fmt"
 	"os/exec"
 	"path/filepath"
 	"strings"
@@ -108,3 +110,33 @@ func maintainers(ctx *aflow.Context, args maintainersArgs) (maintainersResult, e
 	}
 	return res, nil
 }
+
+var getRecentCommits = aflow.NewFuncAction("get-recent-commits", recentCommits)
+
+type recentCommitsArgs struct {
+	KernelSrc    string
+	KernelCommit string
+	PatchDiff    string
+}
+
+type recentCommitsResult struct {
+	RecentCommits string
+}
+
+func recentCommits(ctx *aflow.Context, args recentCommitsArgs) (recentCommitsResult, error) {
+	var res recentCommitsResult
+	var files []string
+	for _, file := range vcs.ParseGitDiff([]byte(args.PatchDiff)) {
+		files = append(files, file.Name)
+	}
+	if len(files) == 0 {
+		return res, aflow.FlowError(errors.New("patch diff does not contain any modified files"))
+	}
+	gitArgs := append([]string{"log", "--format=%s", "--no-merges", "-n", "20", args.KernelCommit}, files...)
+	output, err := osutil.RunCmd(10*time.Minute, args.KernelSrc, "git", gitArgs...)
+	if err != nil {
+		return res, aflow.FlowError(fmt.Errorf("%w\n%s", err, output))
+	}
+	res.RecentCommits = string(output)
+	return res, nil
+}
diff --git a/pkg/aflow/flow/patching/actions_test.go b/pkg/aflow/flow/patching/actions_test.go
new file mode 100644
index 000000000..c6f3011e7
--- /dev/null
+++ b/pkg/aflow/flow/patching/actions_test.go
@@ -0,0 +1,59 @@
+// Copyright 2026 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package patching
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/google/syzkaller/pkg/aflow"
+)
+
+func TestRecentCommits(t *testing.T) {
+	// To avoid creating a fake git repo, we use the syzkaller repo itself.
+	// On CI we have a shallow git checkout that does not have the commit.
+	if os.Getenv("CI") != "" {
+		t.Skip("skipping on CI because of shallow git checkout")
+	}
+	aflow.TestAction(t, getRecentCommits, recentCommitsArgs{
+		KernelSrc:    filepath.FromSlash("../../../.."),
+		KernelCommit: "e01a0ca6c12c9851ea7090f13879255ef82291e7",
+		PatchDiff: `
+diff --git a/dashboard/app/ai.go b/dashboard/app/ai.go
+index d4539113c..1d7401e61 100644
+--- a/dashboard/app/ai.go
++++ b/dashboard/app/ai.go
+@@ -1,2 +1,2 @@
+-// Copyright 2025 syzkaller project authors. All rights reserved.
++// Copyright 2026 syzkaller project authors. All rights reserved.
+ // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+diff --git a/syz-cluster/pkg/fuzzconfig/generate.go b/syz-cluster/pkg/fuzzconfig/generate.go
+index fa7d082e6..74ec57b49 100644
+--- a/syz-cluster/pkg/fuzzconfig/generate.go
++++ b/syz-cluster/pkg/fuzzconfig/generate.go
+@@ -1,2 +1,2 @@
+-// Copyright 2025 syzkaller project authors. All rights reserved.
++// Copyright 2026 syzkaller project authors. All rights reserved.
+ // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+`,
+	}, recentCommitsResult{RecentCommits: `dashboard: run patching ai jobs on custom base commits
+dashboard/app: upload AI-generated patches to gerrit
+dashboard: journal user actions on the ai dashboard
+pkg/aflow/trajectory: add token usage
+dashboard/app: add AI job running status
+dashboard: filter AI jobs by workflows
+syz-cluster: disable some trace calls for non-bpf targets
+pkg/aflow: make LLM model per-agent rather than per-flow
+dashboard/app: show crash report on AI job page
+dashboard/app: improve AI UI
+pkg/aflow: allow to specify model per-flow
+dashboard/app: add race harmfullness label
+dashboard/app: add manual AI job triage
+pkg/aflow/flow/assessment: add UAF moderation workflow
+dashboard/app: add support for AI workflows
+syz-cluster: rewrite fuzz config generation
+`,
+	}, "")
+}
diff --git a/pkg/aflow/flow/patching/patching.go b/pkg/aflow/flow/patching/patching.go
index 1906204ec..f8ee75a31 100644
--- a/pkg/aflow/flow/patching/patching.go
+++ b/pkg/aflow/flow/patching/patching.go
@@ -75,6 +75,7 @@ func createPatchingFlow(name string, summaryWindow int) *aflow.Flow {
 				MaxIterations: 10,
 			},
 			getMaintainers,
+			getRecentCommits,
 			&aflow.LLMAgent{
 				Name:          "description-generator",
 				Model:         aflow.BestExpensiveModel,
@@ -222,6 +223,12 @@ Additional description of the patch:
 
 {{.PatchExplanation}}
 
+Here are summaries of recent commits that touched the same files.
+Format the summary line consistently with these, look how prefixes
+are specified, letter capitalization, style, etc. 
+
+{{.RecentCommits}}
+
 {{if titleIsWarning .BugTitle}}
 If the patch removes the WARN_ON macro, refer to the fact that WARN_ON
 must not be used for conditions that can legitimately happen, and that pr_err