Lint imports in standalone modules

pkg/linter/imports_test.go

@@ -0,0 +1,63 @@
+package linter
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestLintModuleImports(t *testing.T) {
+	for _, tc := range []struct {
+		name, content string
+		wantLine      int
+	}{
+		{
+			name:     "standalone missing import",
+			content:  "# Module\n<!-- cheat\nexport local\nimport missing\nvar x := hello\n-->\n",
+			wantLine: 4,
+		},
+		{
+			name: "standalone valid import",
+			content: "# Dependency\n<!-- cheat\nexport dependency\nvar x := hello\n-->\n" +
+				"# Module\n<!-- cheat\nexport local\nimport dependency\n-->\n",
+		},
+		{
+			name:     "ordinary cheat missing import",
+			content:  "# Command\n```sh\necho hello\n```\n<!-- cheat\nimport missing\n-->\n",
+			wantLine: 6,
+		},
+		{
+			name:     "exported cheat missing import reported once",
+			content:  "# Command\n```sh\necho hello\n```\n<!-- cheat\nexport local\nimport missing\n-->\n",
+			wantLine: 7,
+		},
+	} {
+		for _, mode := range []string{"file", "directory"} {
+			t.Run(tc.name+"/"+mode, func(t *testing.T) {
+				dir := t.TempDir()
+				path := filepath.Join(dir, "imports.md")
+				if err := os.WriteFile(path, []byte(tc.content), 0600); err != nil {
+					t.Fatal(err)
+				}
+				target := path
+				if mode == "directory" {
+					target = dir
+				}
+				findings, err := Lint(target)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if tc.wantLine == 0 {
+					if len(findings) != 0 {
+						t.Fatalf("valid import produced findings: %+v", findings)
+					}
+					return
+				}
+				want := Finding{File: path, Line: tc.wantLine, Column: 8, Severity: SeverityError, Message: `import "missing" does not resolve to any exported module`}
+				if len(findings) != 1 || findings[0] != want {
+					t.Fatalf("Lint() = %+v, want [%+v]", findings, want)
+				}
+			})
+		}
+	}
+}

pkg/linter/linter.go

@@ -276,9 +276,19 @@ func checkMissingChainSteps(name string, steps map[int]*parser.Cheat) []Finding
 
 func lintImports(index *parser.CheatIndex) []Finding {
 	var findings []Finding
+	seen := make(map[*parser.Cheat]bool)
 	for _, c := range index.Cheats {
+		seen[c] = true
 		findings = append(findings, lintCheatImports(c, index)...)
 	}
+	for _, module := range index.Modules {
+		for _, c := range module.Cheats {
+			if !seen[c] {
+				seen[c] = true
+				findings = append(findings, lintCheatImports(c, index)...)
+			}
+		}
+	}
 	return findings
 }