[7.1.0] Implement describeKey for more actions

src/main/java/com/google/devtools/build/lib/analysis/actions/SymlinkAction.java

@@ -313,6 +313,11 @@ protected void computeKey(
     }
   }
 
+  @Override
+  public String describeKey() {
+    return String.format("GUID: %s\ninputPath: %s\n", GUID, inputPath);
+  }
+
   @Override
   public String getMnemonic() {
     return targetType == TargetType.EXECUTABLE ? "ExecutableSymlink" : "Symlink";

src/main/java/com/google/devtools/build/lib/analysis/actions/TemplateExpansionAction.java

@@ -195,6 +195,13 @@ protected void computeKey(
     }
   }
 
+  @Override
+  public String describeKey() {
+    return String.format(
+        "GUID: %s\nmakeExecutable: %s\ntemplate: %s\nsubstitutions: %s\n",
+        GUID, makeExecutable, template.getKey(), substitutions);
+  }
+
   @Override
   public String getMnemonic() {
     return "TemplateExpand";

src/main/java/com/google/devtools/build/lib/analysis/starlark/UnresolvedSymlinkAction.java

@@ -93,6 +93,11 @@ protected void computeKey(
     fp.addPath(target);
   }
 
+  @Override
+  public String describeKey() {
+    return String.format("GUID: %s\ntarget: %s\n", GUID, target);
+  }
+
   @Override
   public String getMnemonic() {
     return "UnresolvedSymlink";