From 466a1ebd073f9b32cbc5d4dd9743c5d8b39b2771 Mon Sep 17 00:00:00 2001
From: Camden Cheek <camden@ccheek.com>
Date: Tue, 8 Aug 2023 13:42:34 -0600
Subject: [PATCH 1/3] add unused linter

---
 BUILD.bazel                    |  1 +
 dev/linters/unused/BUILD.bazel | 12 ++++++++++++
 dev/linters/unused/unused.go   | 31 +++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)
 create mode 100644 dev/linters/unused/BUILD.bazel
 create mode 100644 dev/linters/unused/unused.go

diff --git a/BUILD.bazel b/BUILD.bazel
index d40e69681d56..f35e5cc18c06 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -317,6 +317,7 @@ nogo(
             "//dev/linters/gocritic",
             "//dev/linters/ineffassign",
             "//dev/linters/unparam",
+            "//dev/linters/unused",
         ] + STATIC_CHECK_ANALYZERS,
     }),
 )
diff --git a/dev/linters/unused/BUILD.bazel b/dev/linters/unused/BUILD.bazel
new file mode 100644
index 000000000000..d6f287dc6da8
--- /dev/null
+++ b/dev/linters/unused/BUILD.bazel
@@ -0,0 +1,12 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "unused",
+    srcs = ["unused.go"],
+    importpath = "github.com/sourcegraph/sourcegraph/dev/linters/unused",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@co_honnef_go_tools//unused",
+        "@org_golang_x_tools//go/analysis",
+    ],
+)
diff --git a/dev/linters/unused/unused.go b/dev/linters/unused/unused.go
new file mode 100644
index 000000000000..5e247a096c74
--- /dev/null
+++ b/dev/linters/unused/unused.go
@@ -0,0 +1,31 @@
+package unused
+
+import (
+	"fmt"
+	"go/token"
+
+	"golang.org/x/tools/go/analysis"
+	"honnef.co/go/tools/unused"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name: "unused",
+	Doc:  unused.Analyzer.Analyzer.Doc,
+	Run: func(pass *analysis.Pass) (interface{}, error) {
+		res, err := unused.Analyzer.Analyzer.Run(pass)
+		if err != nil {
+			return res, err
+		}
+		allUnused := res.(unused.Result).Unused
+		for _, u := range allUnused {
+			pass.Report(analysis.Diagnostic{
+				Pos:     token.Pos(u.Position.Offset),
+				Message: fmt.Sprintf("%s is unused", u.Name),
+			})
+		}
+		return res, err
+	},
+	Requires:   unused.Analyzer.Analyzer.Requires,
+	ResultType: unused.Analyzer.Analyzer.ResultType,
+	FactTypes:  []analysis.Fact{},
+}

From 2bb3647dc1640d2b178f79dbc3569a77b4ce3ce6 Mon Sep 17 00:00:00 2001
From: Camden Cheek <camden@ccheek.com>
Date: Tue, 8 Aug 2023 14:12:18 -0600
Subject: [PATCH 2/3] disable unused by default

---
 BUILD.bazel | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/BUILD.bazel b/BUILD.bazel
index f35e5cc18c06..49721eb64d88 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -317,7 +317,8 @@ nogo(
             "//dev/linters/gocritic",
             "//dev/linters/ineffassign",
             "//dev/linters/unparam",
-            "//dev/linters/unused",
+            # Disabled because we currently have a lot of unused code
+            # "//dev/linters/unused",
         ] + STATIC_CHECK_ANALYZERS,
     }),
 )

From 0c0b4642d2fb5494819c7dbff2baba49fbaaa5fb Mon Sep 17 00:00:00 2001
From: Camden Cheek <camden@ccheek.com>
Date: Tue, 8 Aug 2023 14:23:53 -0600
Subject: [PATCH 3/3] make it an idiomatic wrapper

---
 dev/linters/unused/BUILD.bazel |  1 +
 dev/linters/unused/unused.go   | 24 ++++++++++++------------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/dev/linters/unused/BUILD.bazel b/dev/linters/unused/BUILD.bazel
index d6f287dc6da8..54669035cd97 100644
--- a/dev/linters/unused/BUILD.bazel
+++ b/dev/linters/unused/BUILD.bazel
@@ -6,6 +6,7 @@ go_library(
     importpath = "github.com/sourcegraph/sourcegraph/dev/linters/unused",
     visibility = ["//visibility:public"],
     deps = [
+        "//dev/linters/nolint",
         "@co_honnef_go_tools//unused",
         "@org_golang_x_tools//go/analysis",
     ],
diff --git a/dev/linters/unused/unused.go b/dev/linters/unused/unused.go
index 5e247a096c74..738e084b817b 100644
--- a/dev/linters/unused/unused.go
+++ b/dev/linters/unused/unused.go
@@ -3,29 +3,29 @@ package unused
 import (
 	"fmt"
 	"go/token"
+	"reflect"
 
+	"github.com/sourcegraph/sourcegraph/dev/linters/nolint"
 	"golang.org/x/tools/go/analysis"
 	"honnef.co/go/tools/unused"
 )
 
-var Analyzer = &analysis.Analyzer{
+var Analyzer = nolint.Wrap(&analysis.Analyzer{
 	Name: "unused",
-	Doc:  unused.Analyzer.Analyzer.Doc,
+	Doc:  "Unused code",
 	Run: func(pass *analysis.Pass) (interface{}, error) {
-		res, err := unused.Analyzer.Analyzer.Run(pass)
-		if err != nil {
-			return res, err
-		}
-		allUnused := res.(unused.Result).Unused
+		// This is just a lightweight wrapper around the default unused
+		// analyzer that reports a diagnostic error rather than just returning
+		// a result
+		allUnused := pass.ResultOf[unused.Analyzer.Analyzer].(unused.Result).Unused
 		for _, u := range allUnused {
 			pass.Report(analysis.Diagnostic{
 				Pos:     token.Pos(u.Position.Offset),
 				Message: fmt.Sprintf("%s is unused", u.Name),
 			})
 		}
-		return res, err
+		return nil, nil
 	},
-	Requires:   unused.Analyzer.Analyzer.Requires,
-	ResultType: unused.Analyzer.Analyzer.ResultType,
-	FactTypes:  []analysis.Fact{},
-}
+	Requires:   []*analysis.Analyzer{unused.Analyzer.Analyzer},
+	ResultType: reflect.TypeOf(nil),
+})