Add a CI check for unreachable code using deadcode (#251)

Add a CI check for unreachable code using the [`deadcode`
tool](https://go.dev/blog/deadcode).

Remove 3 unused functions that were detected by the tool.

.github/workflows/build.yml

@@ -75,6 +75,30 @@ jobs:
             exit 1
           fi
 
+  dead-code-check:
+    name: dead code check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: '1.21'
+
+      - name: Install deadcode tool
+        run: |
+          go install golang.org/x/tools/cmd/deadcode@latest
+
+      - name: Run deadcode analysis
+        run: |
+          deadcode --test ./... > deadcode.out
+          if [ -s deadcode.out ]; then
+            echo "Dead code analysis found the following dead code:"
+            cat deadcode.out
+            exit 1
+          fi
+
   license-check:
     name: license check
     runs-on: ubuntu-latest
@@ -124,7 +148,7 @@ jobs:
 
   release:
     runs-on: ubuntu-latest
-    needs: [test, lint, examples, license-check, type-generation]
+    needs: [test, lint, examples, license-check, type-generation, dead-code-check]
     if: startsWith(github.ref, 'refs/tags/')
     env:
       DOCKER_CLI_EXPERIMENTAL: "enabled"

pkg/migrations/op_common.go

@@ -7,7 +7,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"strings"
 )
 
 type OpName string
@@ -40,10 +39,6 @@ func TemporaryName(name string) string {
 	return temporaryPrefix + name
 }
 
-func StripTemporaryPrefix(name string) string {
-	return strings.TrimPrefix(name, temporaryPrefix)
-}
-
 func ReadMigration(r io.Reader) (*Migration, error) {
 	byteValue, err := io.ReadAll(r)
 	if err != nil {

pkg/migrations/op_common_test.go

@@ -167,13 +167,6 @@ func TableMustHaveColumnCount(t *testing.T, db *sql.DB, schema, table string, n
 	}
 }
 
-func FunctionMustExist(t *testing.T, db *sql.DB, schema, function string) {
-	t.Helper()
-	if !functionExists(t, db, schema, function) {
-		t.Fatalf("Expected function %q to exist", function)
-	}
-}
-
 func FunctionMustNotExist(t *testing.T, db *sql.DB, schema, function string) {
 	t.Helper()
 	if functionExists(t, db, schema, function) {
@@ -188,13 +181,6 @@ func TriggerMustNotExist(t *testing.T, db *sql.DB, schema, table, trigger string
 	}
 }
 
-func TriggerMustExist(t *testing.T, db *sql.DB, schema, table, trigger string) {
-	t.Helper()
-	if !triggerExists(t, db, schema, table, trigger) {
-		t.Fatalf("Expected trigger %q to exist", trigger)
-	}
-}
-
 func CheckConstraintMustNotExist(t *testing.T, db *sql.DB, schema, table, constraint string) {
 	t.Helper()
 	if checkConstraintExists(t, db, schema, table, constraint) {