From ce0b44c8a729e83bf257d732eebcf9a457f39597 Mon Sep 17 00:00:00 2001
From: Kelvin <oppongk139@gmail.com>
Date: Sun, 19 Apr 2026 15:00:08 -0500
Subject: [PATCH] fix: improve shallow clone error for synthetic history

---
 .../app/azldev/core/sources/synthistory.go    | 15 ++++++++++++++
 .../azldev/core/sources/synthistory_test.go   | 20 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/internal/app/azldev/core/sources/synthistory.go b/internal/app/azldev/core/sources/synthistory.go
index 763b9416..5818aa59 100644
--- a/internal/app/azldev/core/sources/synthistory.go
+++ b/internal/app/azldev/core/sources/synthistory.go
@@ -4,6 +4,7 @@
 package sources
 
 import (
+	"errors"
 	"fmt"
 	"log/slog"
 	"path/filepath"
@@ -42,6 +43,20 @@ func MessageAffectsComponent(message, componentName string) bool {
 // whose message contains an "Affects: <componentName>" trailer line. Results are sorted
 // chronologically (oldest first).
 func FindAffectsCommits(repo *gogit.Repository, componentName string) ([]CommitMetadata, error) {
+	// Synthetic history depends on a complete project commit log so Affects
+	// trailers can be discovered reliably.
+	shallowCommits, err := repo.Storer.Shallow()
+	if err != nil {
+		return nil, fmt.Errorf("failed to inspect repository history depth:\n%w", err)
+	}
+
+	if len(shallowCommits) > 0 {
+		return nil, errors.New(
+			"repository is a shallow clone; synthetic history requires a full clone. " +
+				"Run `git fetch --unshallow` or re-clone without `--depth`",
+		)
+	}
+
 	head, err := repo.Head()
 	if err != nil {
 		return nil, fmt.Errorf("failed to get HEAD reference:\n%w", err)
diff --git a/internal/app/azldev/core/sources/synthistory_test.go b/internal/app/azldev/core/sources/synthistory_test.go
index 24ef8209..506f0a3a 100644
--- a/internal/app/azldev/core/sources/synthistory_test.go
+++ b/internal/app/azldev/core/sources/synthistory_test.go
@@ -10,6 +10,7 @@ import (
 
 	memfs "github.com/go-git/go-billy/v5/memfs"
 	gogit "github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"
 	"github.com/go-git/go-git/v5/storage/memory"
 	"github.com/microsoft/azure-linux-dev-tools/internal/app/azldev/core/sources"
@@ -112,6 +113,25 @@ func TestFindAffectsCommits_NoMatches(t *testing.T) {
 	assert.Empty(t, results)
 }
 
+func TestFindAffectsCommits_ShallowRepo(t *testing.T) {
+	repo := createInMemoryRepo(t)
+
+	addCommit(t, repo,
+		"Fix CVE-2025-1234\n\nAffects: curl",
+		"Alice", "alice@example.com",
+		time.Date(2025, 1, 1, 10, 0, 0, 0, time.UTC))
+
+	head, err := repo.Head()
+	require.NoError(t, err)
+	require.NoError(t, repo.Storer.SetShallow([]plumbing.Hash{head.Hash()}))
+
+	results, err := sources.FindAffectsCommits(repo, "curl")
+	require.Error(t, err)
+	assert.Nil(t, results)
+	assert.Contains(t, err.Error(), "shallow clone")
+	assert.Contains(t, err.Error(), "git fetch --unshallow")
+}
+
 func TestFindAffectsCommits_MultipleComponents(t *testing.T) {
 	repo := createInMemoryRepo(t)