From 8d611fb5d7eb91edcfcb0b9aaba9941b2ecf8b2b Mon Sep 17 00:00:00 2001
From: Andrew Chang <typealiased@gmail.com>
Date: Fri, 24 Dec 2021 04:28:52 -1000
Subject: [PATCH] Show help message no mockable types are generated

---
 .../Handlers/Generator+Pipeline.swift         |  1 +
 .../Generator/Operations/FileGenerator.swift  | 22 ++++++++++++++++---
 .../Operations/GenerateFileOperation.swift    |  3 +++
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/Sources/MockingbirdCli/Interface/Handlers/Generator+Pipeline.swift b/Sources/MockingbirdCli/Interface/Handlers/Generator+Pipeline.swift
index 9d610c82..a5d969dc 100644
--- a/Sources/MockingbirdCli/Interface/Handlers/Generator+Pipeline.swift
+++ b/Sources/MockingbirdCli/Interface/Handlers/Generator+Pipeline.swift
@@ -89,6 +89,7 @@ extension Generator {
         findMockedTypesResult: findMockedTypesOperation?.result,
         config: GenerateFileConfig(
           moduleName: moduleName,
+          testTargetName: config.environmentTargetName,
           outputPath: outputPath,
           header: config.header,
           compilationCondition: config.compilationCondition,
diff --git a/Sources/MockingbirdGenerator/Generator/Operations/FileGenerator.swift b/Sources/MockingbirdGenerator/Generator/Operations/FileGenerator.swift
index 3f1a0bb0..eebac36e 100644
--- a/Sources/MockingbirdGenerator/Generator/Operations/FileGenerator.swift
+++ b/Sources/MockingbirdGenerator/Generator/Operations/FileGenerator.swift
@@ -90,8 +90,14 @@ class FileGenerator {
   }
   
   private func generateFileBody() -> PartialFileContent {
-    guard !mockableTypes.isEmpty else { return PartialFileContent(contents: "") }
-    let operations = mockableTypes
+    guard !mockableTypes.isEmpty else {
+      return PartialFileContent(contents: """
+      // No mockable types in \(singleQuoted: config.moduleName). Check that the module's
+      // source files have classes or protocols that are not private and not marked as final.
+      """)
+    }
+    
+    let availableMockableTypes = mockableTypes
       .filter({ mockableType in
         switch config.pruningMethod {
         case .omit:
@@ -100,6 +106,16 @@ class FileGenerator {
         case .disable, .stub: return true
         }
       })
+    guard !availableMockableTypes.isEmpty else {
+      let testTarget = config.testTargetName?.singleQuoted ?? "your test target"
+      return PartialFileContent(contents: """
+      // No mocks used in \(testTarget). Mockingbird is configured to
+      // only generate mocks for types that are explicitly initialized in your tests with
+      // `mock(SomeType.self)`. For more information, see 'Thunk Pruning' in the README.
+      """)
+    }
+      
+    let operations = availableMockableTypes
       .sorted(by: <)
       .flatMap({ mockableType -> [RenderTemplateOperation] in
         let mockableTypeTemplate = MockableTypeTemplate(mockableType: mockableType,
@@ -137,7 +153,7 @@ class FileGenerator {
                               substructure: [generateFileHeader(),
                                              generateFileBody(),
                                              generateFileFooter()].filter({ !$0.isEmpty }),
-                              delimiter: "\n",
+                              delimiter: "\n\n",
                               footer: "\n")
   }
   
diff --git a/Sources/MockingbirdGenerator/Generator/Operations/GenerateFileOperation.swift b/Sources/MockingbirdGenerator/Generator/Operations/GenerateFileOperation.swift
index 4b349e53..0ea07360 100644
--- a/Sources/MockingbirdGenerator/Generator/Operations/GenerateFileOperation.swift
+++ b/Sources/MockingbirdGenerator/Generator/Operations/GenerateFileOperation.swift
@@ -12,6 +12,7 @@ import os.log
 
 public struct GenerateFileConfig {
   let moduleName: String
+  let testTargetName: String?
   let outputPath: Path
   let header: [String]
   let compilationCondition: String?
@@ -20,6 +21,7 @@ public struct GenerateFileConfig {
   let pruningMethod: PruningMethod
   
   public init(moduleName: String,
+              testTargetName: String?,
               outputPath: Path,
               header: [String],
               compilationCondition: String?,
@@ -27,6 +29,7 @@ public struct GenerateFileConfig {
               disableSwiftlint: Bool,
               pruningMethod: PruningMethod) {
     self.moduleName = moduleName
+    self.testTargetName = testTargetName
     self.outputPath = outputPath
     self.header = header
     self.compilationCondition = compilationCondition