Improve cfg-related warning messages by including a link to the relevant documentation.

Fixes #1877.

--
MOS_MIGRATED_REVID=138199724

1 files changed, 10 insertions, 7 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
index 71f176dc21..310b23d4d0 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
@@ -91,7 +91,8 @@ public final class SkylarkAttr {
 
   private static final String CONFIGURATION_ARG = "cfg";
   private static final String CONFIGURATION_DOC =
-      "configuration of the attribute. It can be either \"data\" or \"host\".";
+      "configuration of the attribute. It can be either \"data\" or \"host\". This parameter is "
+          + "required if <code>executable</code> is True.";
 
   private static final String DEFAULT_ARG = "default";
   private static final String DEFAULT_DOC = "the default value of the attribute.";
@@ -202,8 +203,10 @@ public final class SkylarkAttr {
     if (containsNonNoneKey(arguments, EXECUTABLE_ARG) && (Boolean) arguments.get(EXECUTABLE_ARG)) {
       builder.setPropertyFlag("EXECUTABLE");
       if (!containsNonNoneKey(arguments, CONFIGURATION_ARG)) {
-        String message = "Argument `cfg = \"host\"` or `cfg = \"data\"` is required if"
-            + " `executable = True` is provided for a label";
+        String message = "Argument `cfg = \"host\"` or `cfg = \"data\"` is required if "
+            + "`executable = True` is provided for a label. Please see "
+            + "https://www.bazel.build/versions/master/docs/skylark/rules.html#configurations "
+            + "for more details.";
         env.handleEvent(Event.warn(loc, message));
       }
     }
@@ -270,8 +273,8 @@ public final class SkylarkAttr {
       Object trans = arguments.get(CONFIGURATION_ARG);
       if (trans instanceof ConfigurationTransition) {
         // TODO(laurentlb): Deprecated, to be removed in August 2016.
-        String message = "Variables HOST_CFG and DATA_CFG are deprecated in favor of strings"
-            + " \"host\" and \"data\" correspondingly";
+        String message = "Variables HOST_CFG and DATA_CFG are deprecated in favor of strings "
+            + "\"host\" and \"data\" correspondingly";
         env.handleEvent(Event.warn(loc, message));
         builder.cfg((ConfigurationTransition) trans);
       } else if (trans.equals("data")) {
@@ -1255,8 +1258,8 @@ public final class SkylarkAttr {
     name = "attr_defintion",
     category = SkylarkModuleCategory.NONE,
     doc =
-        "Representation of a definition of an attribute; constructed by <code>attr.*</code>"
-            + " functions. They are only for use with <a href=\"globals.html#rule\">rule</a> or "
+        "Representation of a definition of an attribute; constructed by <code>attr.*</code> "
+            + "functions. They are only for use with <a href=\"globals.html#rule\">rule</a> or "
             + "<a href=\"globals.html#aspect\">aspect</a>."
 
   )