commit a60c6a4b76d6bdf49c3307eb6cb81f9796aaa359
author brandjon <brandjon@google.com> Thu Dec 21 05:53:21 2017 -0800
committer Copybara-Service <copybara-piper@google.com> Thu Dec 21 05:55:13 2017 -0800
tree 6444a00c72b5c80a72d4faa39501f9782bfcbd45
parent bfb8e8f3ed1779d6e5960824b7c651df8a634bbd

Refactor SkylarkProvider constructors and add tests

A new constructor is exposed for building an already-exported SkylarkProvider. The existing constructor no longer takes a name argument (since it was almost entirely ignored). The contract around the name arg for BaseFunction has been refined: it is null if the subclass provides its own naming mechanism.

RELNOTES: None
PiperOrigin-RevId: 179804491

src/main/java/com/google/devtools/build/lib/packages/Provider.java

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 b497b76..2616a20 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
@@ -31,7 +31,9 @@
  * {@link SkylarkProvider}.
  *
  * <p>{@link Provider} serves both as "type identifier" for declared provider instances and as a
- * function that can be called to construct a provider.
+ * function that can be called to construct a provider. To the Skylark user, there are "providers"
+ * and "provider instances"; the former is a Java instance of this class, and the latter is a Java
+ * instance of {@link Info}.
  *
  * <p>Prefer to use {@link Key} as a serializable identifier of {@link Provider}. In particular,
  * {@link Key} should be used in all data structures exposed to Skyframe.
@@ -62,8 +64,19 @@
 @Immutable
 public abstract class Provider extends BaseFunction {
 
+  /**
+   * Constructs a provider.
+   *
+   * @param name provider name; should be null iff the subclass overrides {@link #getName}
+   * @param signature the signature for calling this provider as a Skylark function (to construct an
+   *     instance of the provider)
+   * @param location the location of this provider's Skylark definition. Use {@link
+   *     Location#BUILTIN} if it is a native provider.
+   */
   protected Provider(
-      String name, FunctionSignature.WithValues<Object, SkylarkType> signature, Location location) {
+      @Nullable String name,
+      FunctionSignature.WithValues<Object, SkylarkType> signature,
+      Location location) {
     super(name, signature, location);
   }