From a57c6cde309d8d6d908ae1fc4e36087b5081f215 Mon Sep 17 00:00:00 2001
From: "Michael B. Gale" <mbg@github.com>
Date: Mon, 2 Feb 2026 14:39:27 +0000
Subject: [PATCH] Add `EmitPrivateRegistryUsed`

---
 go/extractor/diagnostics/diagnostics.go      | 21 ++++++++++++++++++++
 go/extractor/diagnostics/diagnostics_test.go | 21 ++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/go/extractor/diagnostics/diagnostics.go b/go/extractor/diagnostics/diagnostics.go
index a91a9efac0d..b40b31c15f3 100644
--- a/go/extractor/diagnostics/diagnostics.go
+++ b/go/extractor/diagnostics/diagnostics.go
@@ -568,3 +568,24 @@ func EmitExtractionFailedForProjects(path []string) {
 		noLocation,
 	)
 }
+
+func EmitPrivateRegistryUsed(writer DiagnosticsWriter, configs []string) {
+	lines := []string{}
+
+	for i := range configs {
+		lines = append(lines, fmt.Sprintf("* %s", configs[i]))
+	}
+
+	emitDiagnosticTo(
+		writer,
+		"go/autobuilder/analysis-using-private-registries",
+		"Go extraction used private package registries",
+		fmt.Sprintf(
+			"Go was extracted using the following private package registrie%s:\n\n%s\n",
+			plural(len(lines), "", "s"),
+			strings.Join(lines, "\n")),
+		severityNote,
+		fullVisibility,
+		noLocation,
+	)
+}
diff --git a/go/extractor/diagnostics/diagnostics_test.go b/go/extractor/diagnostics/diagnostics_test.go
index f2b560004ba..1582923fb55 100644
--- a/go/extractor/diagnostics/diagnostics_test.go
+++ b/go/extractor/diagnostics/diagnostics_test.go
@@ -83,3 +83,24 @@ func Test_EmitCannotFindPackages_Actions(t *testing.T) {
 	// Custom build command suggestion
 	assert.Contains(t, d.MarkdownMessage, "If any of the packages are already present in the repository")
 }
+
+func Test_EmitPrivateRegistryUsed(t *testing.T) {
+	writer := newMemoryDiagnosticsWriter()
+
+	testItems := []string{
+		"* https://github.com/github/example (Git Source)",
+		"* https://example.com/goproxy (GOPROXY Server)",
+	}
+
+	EmitPrivateRegistryUsed(writer, testItems)
+
+	assert.Len(t, writer.diagnostics, 1, "Expected one diagnostic to be emitted")
+
+	d := writer.diagnostics[0]
+	assert.Equal(t, d.Source.Id, "go/autobuilder/analysis-using-private-registries")
+	assert.Equal(t, d.Severity, string(severityNote))
+
+	for i := range testItems {
+		assert.Contains(t, d.MarkdownMessage, testItems[i])
+	}
+}