Rename some ClassObject/Provider-related methods

The terminology "field" is preferred over "key" for the components of a struct or struct-like object.

RELNOTES: None
PiperOrigin-RevId: 180269374

30 files changed, 153 insertions, 153 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredTarget.java b/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredTarget.java
index 872a153777..d1aa8878fd 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredTarget.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/ConfiguredTarget.java
@@ -20,6 +20,7 @@ import com.google.devtools.build.lib.analysis.configuredtargets.InputFileConfigu
 import com.google.devtools.build.lib.packages.Target;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
 import com.google.devtools.build.lib.syntax.ClassObject;
+import com.google.devtools.build.lib.syntax.EvalException;
 import javax.annotation.Nullable;
 
 /**
@@ -63,11 +64,11 @@ public interface ConfiguredTarget extends TransitiveInfoCollection, ClassObject,
   /**
    * Returns keys for a legacy Skylark provider.
    *
-   * Overrides {@link ClassObject#getKeys()}, but does not allow {@link EvalException} to
+   * Overrides {@link ClassObject#getFieldNames()}, but does not allow {@link EvalException} to
    * be thrown.
    */
   @Override
-  ImmutableCollection<String> getKeys();
+  ImmutableCollection<String> getFieldNames();
 
   /**
    * Returns a legacy Skylark provider.
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java
index a9b5461759..9af9811a50 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/DefaultInfo.java
@@ -96,7 +96,7 @@ public final class DefaultInfo extends NativeInfo {
   }
 
   @Override
-  public ImmutableCollection<String> getKeys() {
+  public ImmutableCollection<String> getFieldNames() {
     return KEYS;
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/OutputGroupInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/OutputGroupInfo.java
index 8c313d091d..73c1f8bcfa 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/OutputGroupInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/OutputGroupInfo.java
@@ -252,7 +252,7 @@ public final class OutputGroupInfo extends NativeInfo
   }
 
   @Override
-  public ImmutableCollection<String> getKeys() {
+  public ImmutableCollection<String> getFieldNames() {
     return outputGroups.keySet();
   }
 
@@ -281,8 +281,8 @@ public final class OutputGroupInfo extends NativeInfo
     }
 
     @Override
-    public String getErrorMessageFormatForInstances() {
-      return "Output group %s not present";
+    public String getErrorMessageFormatForUnknownField() {
+      return "Output group '%s' not present";
     }
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentCollection.java b/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentCollection.java
index d0a779c1c7..d11e3bd5be 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentCollection.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentCollection.java
@@ -53,21 +53,21 @@ public class FragmentCollection implements ClassObject {
   }
 
   @Override
-  public ImmutableCollection<String> getKeys() {
+  public ImmutableCollection<String> getFieldNames() {
     return ruleContext.getSkylarkFragmentNames(transition);
   }
 
   @Override
   @Nullable
-  public String errorMessage(String name) {
+  public String getErrorMessageForUnknownField(String name) {
     return String.format(
         "There is no configuration fragment named '%s' in %s configuration. "
         + "Available fragments: %s",
-        name, getConfigurationName(transition), printKeys());
+        name, getConfigurationName(transition), fieldsToString());
   }
 
-  private String printKeys() {
-    return String.format("'%s'", Joiner.on("', '").join(getKeys()));
+  private String fieldsToString() {
+    return String.format("'%s'", Joiner.on("', '").join(getFieldNames()));
   }
 
   public static String getConfigurationName(Transition config) {
@@ -76,6 +76,6 @@ public class FragmentCollection implements ClassObject {
 
   @Override
   public String toString() {
-    return getConfigurationName(transition) + ": [ " + printKeys() + "]";
+    return getConfigurationName(transition) + ": [ " + fieldsToString() + "]";
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/AbstractConfiguredTarget.java b/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/AbstractConfiguredTarget.java
index ca2fc81fc3..c00f385c8e 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/AbstractConfiguredTarget.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/AbstractConfiguredTarget.java
@@ -152,12 +152,12 @@ public abstract class AbstractConfiguredTarget
   }
 
   @Override
-  public String errorMessage(String name) {
+  public String getErrorMessageForUnknownField(String name) {
     return null;
   }
 
   @Override
-  public final ImmutableCollection<String> getKeys() {
+  public final ImmutableCollection<String> getFieldNames() {
     ImmutableList.Builder<String> result = ImmutableList.builder();
     result.addAll(ImmutableList.of(
         DATA_RUNFILES_FIELD,
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/RuleConfiguredTarget.java b/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/RuleConfiguredTarget.java
index 30959f72be..f79f4cf6db 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/RuleConfiguredTarget.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/configuredtargets/RuleConfiguredTarget.java
@@ -142,7 +142,7 @@ public final class RuleConfiguredTarget extends AbstractConfiguredTarget {
   }
 
   @Override
-  public String errorMessage(String name) {
+  public String getErrorMessageForUnknownField(String name) {
     return Printer.format("%r (rule '%s') doesn't have provider '%s'",
         this, getTarget().getRuleClass(), name);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleClassFunctions.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleClassFunctions.java
index 1879227a38..e27d47963e 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleClassFunctions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleClassFunctions.java
@@ -1062,11 +1062,11 @@ public class SkylarkRuleClassFunctions {
 
         private void printProtoTextMessage(
             ClassObject object, StringBuilder sb, int indent, Location loc) throws EvalException {
-          // For determinism sort the keys alphabetically
-          List<String> keys = new ArrayList<>(object.getKeys());
-          Collections.sort(keys);
-          for (String key : keys) {
-            printProtoTextMessage(key, object.getValue(key), sb, indent, loc);
+          // For determinism sort the fields alphabetically.
+          List<String> fields = new ArrayList<>(object.getFieldNames());
+          Collections.sort(fields);
+          for (String field : fields) {
+            printProtoTextMessage(field, object.getValue(field), sb, indent, loc);
           }
         }
 
@@ -1175,13 +1175,13 @@ public class SkylarkRuleClassFunctions {
             sb.append("{");
 
             String join = "";
-            for (String subKey : ((ClassObject) value).getKeys()) {
+            for (String field : ((ClassObject) value).getFieldNames()) {
               sb.append(join);
               join = ",";
               sb.append("\"");
-              sb.append(subKey);
+              sb.append(field);
               sb.append("\":");
-              printJson(((ClassObject) value).getValue(subKey), sb, loc, "struct field", subKey);
+              printJson(((ClassObject) value).getValue(field), sb, loc, "struct field", field);
             }
             sb.append("}");
           } else if (value instanceof List) {
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleConfiguredTargetUtil.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleConfiguredTargetUtil.java
index 7f3a3b15b2..b398073f70 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleConfiguredTargetUtil.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleConfiguredTargetUtil.java
@@ -66,7 +66,7 @@ public final class SkylarkRuleConfiguredTargetUtil {
 
   private SkylarkRuleConfiguredTargetUtil() {}
 
-  private static final ImmutableSet<String> DEFAULT_PROVIDER_KEYS =
+  private static final ImmutableSet<String> DEFAULT_PROVIDER_FIELDS =
       ImmutableSet.of("files", "runfiles", "data_runfiles", "default_runfiles", "executable");
 
   /**
@@ -190,7 +190,7 @@ public final class SkylarkRuleConfiguredTargetUtil {
       throws EvalException {
     Location insLoc = insStruct.getCreationLoc();
     FileTypeSet fileTypeSet = FileTypeSet.ANY_FILE;
-    if (insStruct.getKeys().contains("extensions")) {
+    if (insStruct.getFieldNames().contains("extensions")) {
       @SuppressWarnings("unchecked")
       List<String> exts = cast("extensions", insStruct, SkylarkList.class, String.class, insLoc);
       if (exts.isEmpty()) {
@@ -204,12 +204,12 @@ public final class SkylarkRuleConfiguredTargetUtil {
       }
     }
     List<String> dependencyAttributes = Collections.emptyList();
-    if (insStruct.getKeys().contains("dependency_attributes")) {
+    if (insStruct.getFieldNames().contains("dependency_attributes")) {
       dependencyAttributes =
           cast("dependency_attributes", insStruct, SkylarkList.class, String.class, insLoc);
     }
     List<String> sourceAttributes = Collections.emptyList();
-    if (insStruct.getKeys().contains("source_attributes")) {
+    if (insStruct.getFieldNames().contains("source_attributes")) {
       sourceAttributes =
           cast("source_attributes", insStruct, SkylarkList.class, String.class, insLoc);
     }
@@ -280,7 +280,7 @@ public final class SkylarkRuleConfiguredTargetUtil {
         // Old-style struct, but it may contain declared providers
         oldStyleProviders = struct;
 
-        if (struct.hasKey("providers")) {
+        if (struct.hasField("providers")) {
           Iterable iterable = cast("providers", struct, Iterable.class, loc);
           for (Object o : iterable) {
             Info declaredProvider =
@@ -317,7 +317,7 @@ public final class SkylarkRuleConfiguredTargetUtil {
           .getProvider()
           .getKey()
           .equals(DefaultInfo.PROVIDER.getKey())) {
-        parseDefaultProviderKeys(declaredProvider, context, builder);
+        parseDefaultProviderFields(declaredProvider, context, builder);
         defaultProviderProvidedExplicitly = true;
       } else {
         builder.addSkylarkDeclaredProvider(declaredProvider);
@@ -325,31 +325,31 @@ public final class SkylarkRuleConfiguredTargetUtil {
     }
 
     if (!defaultProviderProvidedExplicitly) {
-      parseDefaultProviderKeys(oldStyleProviders, context, builder);
+      parseDefaultProviderFields(oldStyleProviders, context, builder);
     }
 
-    for (String key : oldStyleProviders.getKeys()) {
-      if (DEFAULT_PROVIDER_KEYS.contains(key)) {
-        // These keys have already been parsed above.
+    for (String field : oldStyleProviders.getFieldNames()) {
+      if (DEFAULT_PROVIDER_FIELDS.contains(field)) {
+        // These fields have already been parsed above.
         // If a default provider has been provided explicitly then it's an error that they also
         // occur here.
         if (defaultProviderProvidedExplicitly) {
           throw new EvalException(
               loc,
               "Provider '"
-                  + key
+                  + field
                   + "' should be specified in DefaultInfo if it's provided explicitly.");
         }
-      } else if (key.equals("output_groups")) {
-        addOutputGroups(oldStyleProviders.getValue(key), loc, builder);
-      } else if (key.equals("instrumented_files")) {
+      } else if (field.equals("output_groups")) {
+        addOutputGroups(oldStyleProviders.getValue(field), loc, builder);
+      } else if (field.equals("instrumented_files")) {
         Info insStruct = cast("instrumented_files", oldStyleProviders, Info.class, loc);
         addInstrumentedFiles(insStruct, context.getRuleContext(), builder);
-      } else if (isNativeDeclaredProviderWithLegacySkylarkName(oldStyleProviders.getValue(key))) {
-        builder.addNativeDeclaredProvider((Info) oldStyleProviders.getValue(key));
-      } else if (!key.equals("providers")) {
+      } else if (isNativeDeclaredProviderWithLegacySkylarkName(oldStyleProviders.getValue(field))) {
+        builder.addNativeDeclaredProvider((Info) oldStyleProviders.getValue(field));
+      } else if (!field.equals("providers")) {
         // We handled providers already.
-        builder.addSkylarkTransitiveInfo(key, oldStyleProviders.getValue(key), loc);
+        builder.addSkylarkTransitiveInfo(field, oldStyleProviders.getValue(field), loc);
       }
     }
   }
@@ -362,10 +362,10 @@ public final class SkylarkRuleConfiguredTargetUtil {
   }
 
   /**
-   * Parses keys of (not necessarily a default) provider. If it is an actual default provider,
-   * throws an {@link EvalException} if there are unknown keys.
+   * Parses fields of (not necessarily a default) provider. If it is an actual default provider,
+   * throws an {@link EvalException} if there are unknown fields.
    */
-  private static void parseDefaultProviderKeys(
+  private static void parseDefaultProviderFields(
       Info provider, SkylarkRuleContext context, RuleConfiguredTargetBuilder builder)
       throws EvalException {
     SkylarkNestedSet files = null;
@@ -376,23 +376,23 @@ public final class SkylarkRuleConfiguredTargetUtil {
 
     Location loc = provider.getCreationLoc();
 
-    for (String key : provider.getKeys()) {
-      if (key.equals("files")) {
+    for (String field : provider.getFieldNames()) {
+      if (field.equals("files")) {
         files = cast("files", provider, SkylarkNestedSet.class, Artifact.class, loc);
-      } else if (key.equals("runfiles")) {
+      } else if (field.equals("runfiles")) {
         statelessRunfiles = cast("runfiles", provider, Runfiles.class, loc);
-      } else if (key.equals("data_runfiles")) {
+      } else if (field.equals("data_runfiles")) {
         dataRunfiles = cast("data_runfiles", provider, Runfiles.class, loc);
-      } else if (key.equals("default_runfiles")) {
+      } else if (field.equals("default_runfiles")) {
         defaultRunfiles = cast("default_runfiles", provider, Runfiles.class, loc);
-      } else if (key.equals("executable")) {
+      } else if (field.equals("executable")) {
         executable = cast("executable", provider, Artifact.class, loc);
       } else if (provider
           .getProvider()
           .getKey()
           .equals(DefaultInfo.PROVIDER.getKey())) {
-        // Custom keys are not allowed for default providers
-        throw new EvalException(loc, "Invalid key for default provider: " + key);
+        // Custom fields are not allowed for default providers
+        throw new EvalException(loc, "Invalid field for default provider: " + field);
       }
     }
 
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java
index 1bcc46c5ed..3f8a54a71b 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleContext.java
@@ -366,7 +366,7 @@ public final class SkylarkRuleContext implements SkylarkValue {
     }
 
     @Override
-    public ImmutableCollection<String> getKeys() throws EvalException {
+    public ImmutableCollection<String> getFieldNames() throws EvalException {
       checkMutable();
       ImmutableList.Builder<String> result = ImmutableList.builder();
       if (context.isExecutable() && executableCreated) {
@@ -391,7 +391,7 @@ public final class SkylarkRuleContext implements SkylarkValue {
 
     @Nullable
     @Override
-    public String errorMessage(String name) {
+    public String getErrorMessageForUnknownField(String name) {
       return String.format(
           "No attribute '%s' in outputs. Make sure you declared a rule output with this name.",
           name);
@@ -407,16 +407,16 @@ public final class SkylarkRuleContext implements SkylarkValue {
       }
       boolean first = true;
       printer.append("ctx.outputs(");
-      // Sort by key to ensure deterministic output.
+      // Sort by field name to ensure deterministic output.
       try {
-        for (String key : Ordering.natural().sortedCopy(getKeys())) {
+        for (String field : Ordering.natural().sortedCopy(getFieldNames())) {
           if (!first) {
             printer.append(", ");
           }
           first = false;
-          printer.append(key);
+          printer.append(field);
           printer.append(" = ");
-          printer.repr(getValue(key));
+          printer.repr(getValue(field));
         }
         printer.append(")");
       } catch (EvalException e) {
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Info.java b/src/main/java/com/google/devtools/build/lib/packages/Info.java
index 550ef181ea..b885d65581 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Info.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Info.java
@@ -70,14 +70,14 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
   public Info(Provider provider, @Nullable Location location) {
     this.provider = provider;
     this.creationLoc = location == null ? Location.BUILTIN : location;
-    this.errorMessageFormatForUnknownField = provider.getErrorMessageFormatForInstances();
+    this.errorMessageFormatForUnknownField = provider.getErrorMessageFormatForUnknownField();
   }
 
   /** Creates a built-in struct (i.e. without a Skylark creation location). */
   public Info(Provider provider) {
     this.provider = provider;
     this.creationLoc = Location.BUILTIN;
-    this.errorMessageFormatForUnknownField = provider.getErrorMessageFormatForInstances();
+    this.errorMessageFormatForUnknownField = provider.getErrorMessageFormatForUnknownField();
   }
 
   /**
@@ -113,10 +113,9 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
   /**
    * Returns whether the given field name exists.
    *
-   * <p>The "key" nomenclature is historic and for consistency with {@link ClassObject}.
+   * <p>This conceptually extends the API for {@link ClassObject}.
    */
-  // TODO(bazel-team): Rename to hasField(), and likewise in ClassObject.
-  public abstract boolean hasKey(String name);
+  public abstract boolean hasField(String name);
 
   /** Returns a value and try to cast it into specified type */
   public <T> T getValue(String key, Class<T> type) throws EvalException {
@@ -144,11 +143,11 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
   /**
    * Returns the fields of this struct.
    *
-   * Overrides {@link ClassObject#getKeys()}, but does not allow {@link EvalException} to
+   * Overrides {@link ClassObject#getFieldNames()}, but does not allow {@link EvalException} to
    * be thrown.
    */
   @Override
-  public abstract ImmutableCollection<String> getKeys();
+  public abstract ImmutableCollection<String> getFieldNames();
 
   /**
    * Returns the value associated with the name field in this struct,
@@ -161,11 +160,10 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
   @Override
   public abstract Object getValue(String name);
 
-  // TODO(bazel-team): Rename to getErrorMessageForUnknownField.
   @Override
-  public String errorMessage(String name) {
-    String suffix =
-        "Available attributes: " + Joiner.on(", ").join(Ordering.natural().sortedCopy(getKeys()));
+  public String getErrorMessageForUnknownField(String name) {
+    String suffix = "Available attributes: "
+        + Joiner.on(", ").join(Ordering.natural().sortedCopy(getFieldNames()));
     return String.format(errorMessageFormatForUnknownField, name) + "\n" + suffix;
   }
 
@@ -181,12 +179,12 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
     if (!this.provider.equals(other.provider)) {
       return false;
     }
-    // Compare objects' keys and values
-    if (!this.getKeys().equals(other.getKeys())) {
+    // Compare objects' fields and their values
+    if (!this.getFieldNames().equals(other.getFieldNames())) {
       return false;
     }
-    for (String key : getKeys()) {
-      if (!this.getValue(key).equals(other.getValue(key))) {
+    for (String field : getFieldNames()) {
+      if (!this.getValue(field).equals(other.getValue(field))) {
         return false;
       }
     }
@@ -195,13 +193,13 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
 
   @Override
   public int hashCode() {
-    List<String> keys = new ArrayList<>(getKeys());
-    Collections.sort(keys);
+    List<String> fields = new ArrayList<>(getFieldNames());
+    Collections.sort(fields);
     List<Object> objectsToHash = new ArrayList<>();
     objectsToHash.add(provider);
-    for (String key : keys) {
-      objectsToHash.add(key);
-      objectsToHash.add(getValue(key));
+    for (String field : fields) {
+      objectsToHash.add(field);
+      objectsToHash.add(getValue(field));
     }
     return Objects.hashCode(objectsToHash.toArray());
   }
@@ -215,14 +213,14 @@ public abstract class Info implements ClassObject, SkylarkValue, Serializable {
     boolean first = true;
     printer.append("struct(");
     // Sort by key to ensure deterministic output.
-    for (String key : Ordering.natural().sortedCopy(getKeys())) {
+    for (String fieldName : Ordering.natural().sortedCopy(getFieldNames())) {
       if (!first) {
         printer.append(", ");
       }
       first = false;
-      printer.append(key);
+      printer.append(fieldName);
       printer.append(" = ");
-      printer.repr(getValue(key));
+      printer.repr(getValue(fieldName));
     }
     printer.append(")");
   }
diff --git a/src/main/java/com/google/devtools/build/lib/packages/NativeInfo.java b/src/main/java/com/google/devtools/build/lib/packages/NativeInfo.java
index d52fa87a1d..e1035c86e9 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/NativeInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/NativeInfo.java
@@ -29,12 +29,12 @@ public class NativeInfo extends Info {
   }
 
   @Override
-  public boolean hasKey(String name) {
+  public boolean hasField(String name) {
     return values.containsKey(name);
   }
 
   @Override
-  public ImmutableCollection<String> getKeys() {
+  public ImmutableCollection<String> getFieldNames() {
     return values.keySet();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/packages/NativeProvider.java b/src/main/java/com/google/devtools/build/lib/packages/NativeProvider.java
index 93bbcfe025..0f78e4659c 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/NativeProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/NativeProvider.java
@@ -40,16 +40,16 @@ import javax.annotation.Nullable;
  * #createInstanceFromSkylark(Object[], Location)} (see {@link #STRUCT} for an example.
  */
 @Immutable
-public abstract class NativeProvider<VALUE extends Info> extends Provider {
+public abstract class NativeProvider<V extends Info> extends Provider {
   private final NativeKey key;
-  private final String errorMessageForInstances;
+  private final String errorMessageFormatForUnknownField;
 
   /** "struct" function. */
   public static final StructConstructor STRUCT = new StructConstructor();
 
-  private final Class<VALUE> valueClass;
+  private final Class<V> valueClass;
 
-  public Class<VALUE> getValueClass() {
+  public Class<V> getValueClass() {
     return valueClass;
   }
 
@@ -94,18 +94,18 @@ public abstract class NativeProvider<VALUE extends Info> extends Provider {
   private static final FunctionSignature.WithValues<Object, SkylarkType> SIGNATURE =
       FunctionSignature.WithValues.create(FunctionSignature.KWARGS);
 
-  protected NativeProvider(Class<VALUE> clazz, String name) {
+  protected NativeProvider(Class<V> clazz, String name) {
     this(clazz, name, SIGNATURE);
   }
 
   protected NativeProvider(
-      Class<VALUE> valueClass,
+      Class<V> valueClass,
       String name,
       FunctionSignature.WithValues<Object, SkylarkType> signature) {
     super(name, signature, Location.BUILTIN);
     key = new NativeKey(name, getClass());
     this.valueClass = valueClass;
-    errorMessageForInstances = String.format("'%s' object has no attribute '%%s'", name);
+    errorMessageFormatForUnknownField = String.format("'%s' object has no attribute '%%s'", name);
   }
 
   /**
@@ -136,8 +136,8 @@ public abstract class NativeProvider<VALUE extends Info> extends Provider {
   }
 
   @Override
-  public String getErrorMessageFormatForInstances() {
-    return errorMessageForInstances;
+  public String getErrorMessageFormatForUnknownField() {
+    return errorMessageFormatForUnknownField;
   }
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Provider.java b/src/main/java/com/google/devtools/build/lib/packages/Provider.java
index 028a03d446..dc06b664ee 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Provider.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Provider.java
@@ -17,6 +17,7 @@ import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.syntax.BaseFunction;
+import com.google.devtools.build.lib.syntax.ClassObject;
 import com.google.devtools.build.lib.syntax.Environment;
 import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.FuncallExpression;
@@ -93,12 +94,12 @@ public abstract class Provider extends BaseFunction {
   public abstract String getPrintableName();
 
   /**
-   * Returns an error message format for instances.
+   * Returns an error message format string for instances to use for their {@link
+   * ClassObject#getErrorMessageForUnknownField(String)}.
    *
-   * <p>Must contain one {@code '%s'} placeholder for field name.
+   * <p>The format string must contain one {@code '%s'} placeholder for the field name.
    */
-  // TODO(bazel-team): Rename to getErrorMessageFormatForUnknownField().
-  public abstract String getErrorMessageFormatForInstances();
+  public abstract String getErrorMessageFormatForUnknownField();
 
   public SkylarkProviderIdentifier id() {
     return SkylarkProviderIdentifier.forKey(getKey());
diff --git a/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java b/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java
index 2025b1e5ba..cc5d3ea93d 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/SkylarkInfo.java
@@ -85,12 +85,12 @@ public abstract class SkylarkInfo extends Info implements Concatable {
     }
 
     @Override
-    public boolean hasKey(String name) {
+    public boolean hasField(String name) {
       return values.containsKey(name);
     }
 
     @Override
-    public ImmutableCollection<String> getKeys() {
+    public ImmutableCollection<String> getFieldNames() {
       return values.keySet();
     }
 
@@ -133,14 +133,14 @@ public abstract class SkylarkInfo extends Info implements Concatable {
     }
 
     @Override
-    public boolean hasKey(String name) {
+    public boolean hasField(String name) {
       Integer index = layout.get(name);
       return index != null && values[index] != null;
     }
 
     @Override
-    public ImmutableCollection<String> getKeys() {
-      ImmutableSet.Builder<String> result = new ImmutableSet.Builder();
+    public ImmutableCollection<String> getFieldNames() {
+      ImmutableSet.Builder<String> result = ImmutableSet.builder();
       for (Map.Entry<String, Integer> entry : layout.entrySet()) {
         if (values[entry.getValue()] != null) {
           result.add(entry.getKey());
@@ -175,7 +175,7 @@ public abstract class SkylarkInfo extends Info implements Concatable {
       }
       SetView<String> commonFields =
           Sets.intersection(
-              ImmutableSet.copyOf(lval.getKeys()), ImmutableSet.copyOf(rval.getKeys()));
+              ImmutableSet.copyOf(lval.getFieldNames()), ImmutableSet.copyOf(rval.getFieldNames()));
       if (!commonFields.isEmpty()) {
         throw new EvalException(
             loc,
@@ -198,11 +198,11 @@ public abstract class SkylarkInfo extends Info implements Concatable {
             compactLeft.getProvider(), compactLeft.layout, newValues, loc);
       }
       ImmutableMap.Builder<String, Object> newValues = ImmutableMap.builder();
-      for (String key : lval.getKeys()) {
-        newValues.put(key, lval.getValue(key));
+      for (String field : lval.getFieldNames()) {
+        newValues.put(field, lval.getValue(field));
       }
-      for (String key : rval.getKeys()) {
-        newValues.put(key, rval.getValue(key));
+      for (String field : rval.getFieldNames()) {
+        newValues.put(field, rval.getValue(field));
       }
       return new MapBackedSkylarkInfo(provider, newValues.build(), loc);
     }
diff --git a/src/main/java/com/google/devtools/build/lib/packages/SkylarkProvider.java b/src/main/java/com/google/devtools/build/lib/packages/SkylarkProvider.java
index 1a94c9cf2b..557b1ca3e8 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/SkylarkProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/SkylarkProvider.java
@@ -48,6 +48,7 @@ public class SkylarkProvider extends Provider implements SkylarkExportable {
   private static final FunctionSignature.WithValues<Object, SkylarkType> SCHEMALESS_SIGNATURE =
       FunctionSignature.WithValues.create(FunctionSignature.KWARGS);
 
+  /** Default value for {@link #errorMessageFormatForUnknownField}. */
   private static final String DEFAULT_ERROR_MESSAGE_FORMAT = "Object has no '%s' attribute.";
 
   /**
@@ -65,7 +66,7 @@ public class SkylarkProvider extends Provider implements SkylarkExportable {
   private SkylarkKey key;
 
   /** Error message format. Reassigned upon exporting. */
-  private String errorMessageFormatForInstances;
+  private String errorMessageFormatForUnknownField;
 
   /**
    * Creates an unexported {@link SkylarkProvider} with no schema.
@@ -132,9 +133,9 @@ public class SkylarkProvider extends Provider implements SkylarkExportable {
     super(/*name=*/ null, buildSignature(fields), location);
     this.layout = buildLayout(fields);
     this.key = key;  // possibly null
-    this.errorMessageFormatForInstances =
+    this.errorMessageFormatForUnknownField =
         key == null ? DEFAULT_ERROR_MESSAGE_FORMAT
-            : makeErrorMessageFormatForInstances(key.getExportedName());
+            : makeErrorMessageFormatForUnknownField(key.getExportedName());
   }
 
 
@@ -209,18 +210,18 @@ public class SkylarkProvider extends Provider implements SkylarkExportable {
   }
 
   @Override
-  public String getErrorMessageFormatForInstances() {
-    return errorMessageFormatForInstances;
+  public String getErrorMessageFormatForUnknownField() {
+    return errorMessageFormatForUnknownField;
   }
 
   @Override
   public void export(Label extensionLabel, String exportedName) {
     Preconditions.checkState(!isExported());
     this.key = new SkylarkKey(extensionLabel, exportedName);
-    this.errorMessageFormatForInstances = makeErrorMessageFormatForInstances(exportedName);
+    this.errorMessageFormatForUnknownField = makeErrorMessageFormatForUnknownField(exportedName);
   }
 
-  private static String makeErrorMessageFormatForInstances(String exportedName) {
+  private static String makeErrorMessageFormatForUnknownField(String exportedName) {
     return String.format("'%s' object has no attribute '%%s'", exportedName);
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java b/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java
index 0c2b15e467..ff5c287f36 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java
@@ -122,12 +122,12 @@ public final class AliasConfiguredTarget implements ConfiguredTarget, ClassObjec
   }
 
   @Override
-  public ImmutableCollection<String> getKeys() {
-    return actual.getKeys();
+  public ImmutableCollection<String> getFieldNames() {
+    return actual.getFieldNames();
   }
 
   @Override
-  public String errorMessage(String name) {
+  public String getErrorMessageForUnknownField(String name) {
     // Use the default error message.
     return null;
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProvider.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProvider.java
index 1eeb89064b..9ac9dcc4b4 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcProvider.java
@@ -1010,8 +1010,8 @@ public final class ObjcProvider extends NativeInfo {
     }
 
     @Override
-    public String getErrorMessageFormatForInstances() {
-      return "ObjcProvider field %s could not be instantiated";
+    public String getErrorMessageFormatForUnknownField() {
+      return "ObjcProvider field '%s' could not be instantiated";
     }
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/XcTestAppProvider.java b/src/main/java/com/google/devtools/build/lib/rules/objc/XcTestAppProvider.java
index 6dc6db113b..09bbad98dc 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/XcTestAppProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/XcTestAppProvider.java
@@ -94,8 +94,8 @@ public final class XcTestAppProvider extends NativeInfo {
     }
 
     @Override
-    public String getErrorMessageFormatForInstances() {
-      return "XcTestAppProvider field %s could not be instantiated";
+    public String getErrorMessageFormatForUnknownField() {
+      return "XcTestAppProvider field '%s' could not be instantiated";
     }
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkAspectFactory.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkAspectFactory.java
index 24112a4fae..d66d30bb55 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkAspectFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkylarkAspectFactory.java
@@ -116,11 +116,11 @@ public class SkylarkAspectFactory implements ConfiguredAspectFactory {
     } else {
       Info struct = (Info) aspectSkylarkObject;
       Location loc = struct.getCreationLoc();
-      for (String key : struct.getKeys()) {
-        if (key.equals("output_groups")) {
-          addOutputGroups(struct.getValue(key), loc, builder);
-        } else if (key.equals("providers")) {
-          Object value = struct.getValue(key);
+      for (String field : struct.getFieldNames()) {
+        if (field.equals("output_groups")) {
+          addOutputGroups(struct.getValue(field), loc, builder);
+        } else if (field.equals("providers")) {
+          Object value = struct.getValue(field);
           Iterable providers =
               SkylarkType.cast(
                   value,
@@ -131,7 +131,7 @@ public class SkylarkAspectFactory implements ConfiguredAspectFactory {
                   EvalUtils.getDataTypeName(value, false));
           addDeclaredProviders(builder, providers);
         } else {
-          builder.addSkylarkTransitiveInfo(key, struct.getValue(key), loc);
+          builder.addSkylarkTransitiveInfo(field, struct.getValue(field), loc);
         }
       }
     }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/ClassObject.java b/src/main/java/com/google/devtools/build/lib/syntax/ClassObject.java
index 93cc35c12f..522ecaa052 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/ClassObject.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/ClassObject.java
@@ -11,20 +11,17 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+
 package com.google.devtools.build.lib.syntax;
 
 import com.google.common.collect.ImmutableCollection;
 import javax.annotation.Nullable;
 
-/**
- * An interface for objects behaving like Skylark structs.
- */
-// TODO(bazel-team): type checks
+/** An interface for Skylark objects (such as structs) that have fields. */
 public interface ClassObject {
 
   /**
-   * Returns the value associated with the name field in this struct,
-   * or null if the field does not exist.
+   * Returns the value of the field with the given name, or null if the field does not exist.
    *
    * @throws EvalException if a user-visible error occurs (other than non-existent field).
    */
@@ -32,15 +29,17 @@ public interface ClassObject {
   Object getValue(String name) throws EvalException;
 
   /**
-   * Returns the fields of this struct.
+   * Returns the names of the fields of this struct, in some canonical order.
    *
-   * @throws EvalException if a user-visible error occurs.
+   * @throws EvalException if a user-visible error occurs
    */
-  ImmutableCollection<String> getKeys() throws EvalException;
+  ImmutableCollection<String> getFieldNames() throws EvalException;
 
   /**
-   * Returns a customized error message to print if the name is not a valid struct field
-   * of this struct, or returns null to use the default error message.
+   * Returns the error message to print for an attempt to access an undefined field.
+   *
+   * <p>May return null to use a default error message.
    */
-  @Nullable String errorMessage(String name);
+  @Nullable
+  String getErrorMessageForUnknownField(String field);
 }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
index 970d0ca14c..8aa0ad92ec 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/DotExpression.java
@@ -65,11 +65,11 @@ public final class DotExpression extends Expression {
     }
     String suffix = "";
     if (objValue instanceof ClassObject) {
-      String customErrorMessage = ((ClassObject) objValue).errorMessage(name);
+      String customErrorMessage = ((ClassObject) objValue).getErrorMessageForUnknownField(name);
       if (customErrorMessage != null) {
         throw new EvalException(loc, customErrorMessage);
       }
-      suffix = SpellChecker.didYouMean(name, ((ClassObject) objValue).getKeys());
+      suffix = SpellChecker.didYouMean(name, ((ClassObject) objValue).getFieldNames());
     }
     throw new EvalException(
         loc,
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java b/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java
index 657d28d4da..f3c0d5f3c1 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/MethodLibrary.java
@@ -2066,7 +2066,7 @@ public class MethodLibrary {
           // Order the fields alphabetically.
           Set<String> fields = new TreeSet<>();
           if (object instanceof ClassObject) {
-            fields.addAll(((ClassObject) object).getKeys());
+            fields.addAll(((ClassObject) object).getFieldNames());
           }
           fields.addAll(Runtime.getBuiltinRegistry().getFunctionNames(object.getClass()));
           fields.addAll(FuncallExpression.getMethodNames(object.getClass()));
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkCallbackFunction.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkCallbackFunction.java
index 719c94b961..60c6aece91 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkCallbackFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkCallbackFunction.java
@@ -64,7 +64,7 @@ public class SkylarkCallbackFunction {
       String name = names.get(pos);
       Object value = ctx.getValue(name);
       if (value == null) {
-          throw new IllegalArgumentException(ctx.errorMessage(name));
+          throw new IllegalArgumentException(ctx.getErrorMessageForUnknownField(name));
       }
       builder.add(value);
     }
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
index 7b716c3f3a..29ed8aad2e 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
@@ -107,7 +107,7 @@ public class SkylarkRepositoryContextTest {
         ImmutableMap.<String, Object>of("name", "test", "foo", "bar"),
         Attribute.attr("foo", Type.STRING).build());
 
-    assertThat(context.getAttr().getKeys()).contains("foo");
+    assertThat(context.getAttr().getFieldNames()).contains("foo");
     assertThat(context.getAttr().getValue("foo")).isEqualTo("bar");
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/packages/SkylarkInfoTest.java b/src/test/java/com/google/devtools/build/lib/packages/SkylarkInfoTest.java
index b57b894b2c..cbcfa4835d 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/SkylarkInfoTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/SkylarkInfoTest.java
@@ -101,7 +101,7 @@ public class SkylarkInfoTest {
         new CompactSkylarkInfo(provider, layout, new Object[] {null, 5}, Location.BUILTIN);
     Concatable result = p1.getConcatter().concat(p1, p2, Location.BUILTIN);
     assertThat(result).isInstanceOf(MapBackedSkylarkInfo.class);
-    assertThat(((SkylarkInfo) result).getKeys()).containsExactly("f1", "f2");
+    assertThat(((SkylarkInfo) result).getFieldNames()).containsExactly("f1", "f2");
     assertThat(((SkylarkInfo) result).getValue("f1")).isEqualTo(4);
     assertThat(((SkylarkInfo) result).getValue("f2")).isEqualTo(5);
   }
@@ -117,7 +117,7 @@ public class SkylarkInfoTest {
         new CompactSkylarkInfo(provider, layout, new Object[] {null, 5}, Location.BUILTIN);
     Concatable result = p1.getConcatter().concat(p1, p2, Location.BUILTIN);
     assertThat(result).isInstanceOf(CompactSkylarkInfo.class);
-    assertThat(((CompactSkylarkInfo) result).getKeys()).containsExactly("f1", "f2");
+    assertThat(((CompactSkylarkInfo) result).getFieldNames()).containsExactly("f1", "f2");
     assertThat(((CompactSkylarkInfo) result).getValue("f1")).isEqualTo(4);
     assertThat(((CompactSkylarkInfo) result).getValue("f2")).isEqualTo(5);
   }
diff --git a/src/test/java/com/google/devtools/build/lib/packages/SkylarkProviderTest.java b/src/test/java/com/google/devtools/build/lib/packages/SkylarkProviderTest.java
index 171bb9f439..26c11763b5 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/SkylarkProviderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/SkylarkProviderTest.java
@@ -37,7 +37,7 @@ public final class SkylarkProviderTest {
     assertThat(provider.isExported()).isFalse();
     assertThat(provider.getName()).isEqualTo("<no name>");
     assertThat(provider.getPrintableName()).isEqualTo("<no name>");
-    assertThat(provider.getErrorMessageFormatForInstances())
+    assertThat(provider.getErrorMessageFormatForUnknownField())
         .isEqualTo("Object has no '%s' attribute.");
     assertThat(provider.isImmutable()).isFalse();
     assertThat(Printer.repr(provider)).isEqualTo("<provider>");
@@ -53,7 +53,7 @@ public final class SkylarkProviderTest {
     assertThat(provider.isExported()).isTrue();
     assertThat(provider.getName()).isEqualTo("prov");
     assertThat(provider.getPrintableName()).isEqualTo("prov");
-    assertThat(provider.getErrorMessageFormatForInstances())
+    assertThat(provider.getErrorMessageFormatForUnknownField())
         .isEqualTo("'prov' object has no attribute '%s'");
     assertThat(provider.isImmutable()).isTrue();
     assertThat(Printer.repr(provider)).isEqualTo("<provider>");
@@ -140,7 +140,7 @@ public final class SkylarkProviderTest {
 
   /** Asserts that a {@link SkylarkInfo} has fields a=1, b=2, c=3 (and nothing else). */
   private static void assertHasExactlyValuesA1B2C3(SkylarkInfo info) {
-    assertThat(info.getKeys()).containsExactly("a", "b", "c");
+    assertThat(info.getFieldNames()).containsExactly("a", "b", "c");
     assertThat(info.getValue("a")).isEqualTo(1);
     assertThat(info.getValue("b")).isEqualTo(2);
     assertThat(info.getValue("c")).isEqualTo(3);
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSelectionTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSelectionTest.java
index 7ba0faa6e0..94ff70e6c4 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSelectionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSelectionTest.java
@@ -124,7 +124,7 @@ public class CcToolchainSelectionTest extends BuildViewTestCase {
             getRuleContext(target).getToolchainContext().getResolvedToolchainProviders();
     ToolchainInfo toolchain =
         providers.getForToolchainType(Label.parseAbsolute(CPP_TOOLCHAIN_TYPE));
-    assertThat(toolchain.getKeys()).isEmpty();
+    assertThat(toolchain.getFieldNames()).isEmpty();
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
index 87561bd3b7..930ba2586c 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
@@ -1051,7 +1051,7 @@ public class SkylarkRuleClassFunctionsTest extends SkylarkTestCase {
         "y = struct(c = 1, d = 2)",
         "z = x + y\n");
     Info z = (Info) lookup("z");
-    assertThat(z.getKeys()).isEqualTo(ImmutableSet.of("a", "b", "c", "d"));
+    assertThat(z.getFieldNames()).isEqualTo(ImmutableSet.of("a", "b", "c", "d"));
   }
 
   @Test
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
index 8dfb22dc5a..877bcf8786 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
@@ -1186,7 +1186,7 @@ public class SkylarkRuleImplementationFunctionsTest extends SkylarkTestCase {
       getConfiguredTarget("//test:my_rule");
       fail();
     } catch (AssertionError expected) {
-      assertThat(expected).hasMessageThat().contains("Invalid key for default provider: foo");
+      assertThat(expected).hasMessageThat().contains("Invalid field for default provider: foo");
     }
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
index 8aaeb88b00..2f9742c117 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
@@ -235,12 +235,12 @@ public class SkylarkEvaluationTest extends EvaluationTest {
     }
 
     @Override
-    public ImmutableCollection<String> getKeys() {
+    public ImmutableCollection<String> getFieldNames() {
       return ImmutableList.of("field", "nset");
     }
 
     @Override
-    public String errorMessage(String name) {
+    public String getErrorMessageForUnknownField(String name) {
       return null;
     }
   }