Parse Proguard flag -keepparameternames

Fail if it actually has an effect.

It is used in AOSP, but always together with -dontobfuscate, and in that
case it has no effect.

Bug: 62524153
Change-Id: I003b1ab6d3ac16c5e1aeb0bd5601834f35d8f772
diff --git a/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java b/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java
index 2560fd6..239f9bc 100644
--- a/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java
+++ b/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java
@@ -45,6 +45,7 @@
     private Path classObfuscationDictionary;
     private Path packageObfuscationDictionary;
     private boolean useUniqueClassMemberNames;
+    private boolean keepParameterNames;
 
     private Builder(DexItemFactory dexItemFactory) {
       this.dexItemFactory = dexItemFactory;
@@ -164,6 +165,14 @@
       return useUniqueClassMemberNames;
     }
 
+    public void setKeepParameterNames(boolean keepParameterNames) {
+      this.keepParameterNames = keepParameterNames;
+    }
+
+    boolean isKeepParameterNames() {
+      return keepParameterNames;
+    }
+
     public ProguardConfiguration build() {
       return new ProguardConfiguration(
           dexItemFactory,
@@ -191,7 +200,8 @@
           DictionaryReader.readAllNames(obfuscationDictionary),
           DictionaryReader.readAllNames(classObfuscationDictionary),
           DictionaryReader.readAllNames(packageObfuscationDictionary),
-          useUniqueClassMemberNames);
+          useUniqueClassMemberNames,
+          keepParameterNames);
     }
   }
 
@@ -221,6 +231,7 @@
   private final ImmutableList<String> classObfuscationDictionary;
   private final ImmutableList<String> packageObfuscationDictionary;
   private boolean useUniqueClassMemberNames;
+  private boolean keepParameterNames;
 
   private ProguardConfiguration(
       DexItemFactory factory,
@@ -248,7 +259,8 @@
       ImmutableList<String> obfuscationDictionary,
       ImmutableList<String> classObfuscationDictionary,
       ImmutableList<String> packageObfuscationDictionary,
-      boolean useUniqueClassMemberNames) {
+      boolean useUniqueClassMemberNames,
+      boolean keepParameterNames) {
     this.dexItemFactory = factory;
     this.injars = ImmutableList.copyOf(injars);
     this.libraryjars = ImmutableList.copyOf(libraryjars);
@@ -275,6 +287,7 @@
     this.classObfuscationDictionary = classObfuscationDictionary;
     this.packageObfuscationDictionary = packageObfuscationDictionary;
     this.useUniqueClassMemberNames = useUniqueClassMemberNames;
+    this.keepParameterNames = keepParameterNames;
   }
 
   /**
@@ -388,6 +401,10 @@
     return useUniqueClassMemberNames;
   }
 
+  public boolean isKeepParameterNames() {
+    return keepParameterNames;
+  }
+
   public static ProguardConfiguration defaultConfiguration(DexItemFactory dexItemFactory) {
     return new DefaultProguardConfiguration(dexItemFactory);
   }
@@ -420,7 +437,8 @@
           ImmutableList.of()    /* obfuscationDictionary */,
           ImmutableList.of()    /* classObfuscationDictionary */,
           ImmutableList.of()    /* packageObfuscationDictionary */,
-          false                 /* useUniqueClassMemberNames*/);
+          false                 /* useUniqueClassMemberNames*/,
+          false                 /* keepParameterNames */);
     }
 
     @Override
diff --git a/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java b/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
index 4784387..08a7eca 100644
--- a/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
+++ b/src/main/java/com/android/tools/r8/shaking/ProguardConfigurationParser.java
@@ -85,6 +85,13 @@
       throw new ProguardRuleParserException("-useuniqueulassmembernames is not supported");
     }
 
+    if (configurationBuilder.isKeepParameterNames()
+        && configurationBuilder.isObfuscating()) {
+      // The flag -keepparameternames has only effect when minifying, so ignore it if we
+      // are not.
+      throw new ProguardRuleParserException("-keepparameternames is not supported");
+    }
+
     return configurationBuilder.build();
   }
 
@@ -156,6 +163,8 @@
       } else if (acceptString("keeppackagenames")) {
         ProguardKeepPackageNamesRule rule = parseKeepPackageNamesRule();
         configurationBuilder.addRule(rule);
+      } else if (acceptString("keepparameternames")) {
+        configurationBuilder.setKeepParameterNames(true);
       } else if (acceptString("checkdiscard")) {
         ProguardCheckDiscardRule rule = parseCheckDiscardRule();
         configurationBuilder.addRule(rule);
diff --git a/src/test/java/com/android/tools/r8/shaking/ProguardConfigurationParserTest.java b/src/test/java/com/android/tools/r8/shaking/ProguardConfigurationParserTest.java
index 9f19536..3f44025 100644
--- a/src/test/java/com/android/tools/r8/shaking/ProguardConfigurationParserTest.java
+++ b/src/test/java/com/android/tools/r8/shaking/ProguardConfigurationParserTest.java
@@ -680,4 +680,40 @@
     config = parser.getConfig();
     assertTrue(config.isUseUniqueClassMemberNames());
   }
+
+  @Test
+  public void parseKeepParameterNames() throws Exception {
+    try {
+      ProguardConfigurationParser parser = new ProguardConfigurationParser(new DexItemFactory());
+      parser.parse(new ProguardConfigurationSourceStrings(ImmutableList.of(
+          "-keepparameternames"
+      )));
+      parser.getConfig();
+      fail();
+    } catch (ProguardRuleParserException e) {
+      System.out.println(e);
+      assertTrue(e.getMessage().contains("-keepparameternames is not supported"));
+    }
+  }
+
+  @Test
+  public void parseKeepParameterNamesWithoutMinification() throws Exception {
+    ProguardConfigurationParser parser = new ProguardConfigurationParser(new DexItemFactory());
+    parser.parse(new ProguardConfigurationSourceStrings(ImmutableList.of(
+        "-keepparameternames",
+        "-dontobfuscate"
+    )));
+    ProguardConfiguration config = parser.getConfig();
+    assertTrue(config.isKeepParameterNames());
+
+    parser = new ProguardConfigurationParser(new DexItemFactory());
+    parser.parse(new ProguardConfigurationSourceStrings(ImmutableList.of(
+        "-keepparameternames"
+    )));
+    parser.parse(new ProguardConfigurationSourceStrings(ImmutableList.of(
+        "-dontobfuscate"
+    )));
+    config = parser.getConfig();
+    assertTrue(config.isKeepParameterNames());
+  }
 }