rules_jvm_external_javadoc.patch

diff --git a/private/rules/javadoc.bzl b/private/rules/javadoc.bzl
index 9b90570..c9b6f09 100644
--- a/private/rules/javadoc.bzl
+++ b/private/rules/javadoc.bzl
@@ -12,10 +12,43 @@ def generate_javadoc(ctx, javadoc, source_jars, classpath, javadocopts, output):
         arguments = [args],
     )

+def _get_prefix_strings(third_party_prefixes):
+    path_prefixes = []
+    for prefix in third_party_prefixes:
+        if prefix.find(":") != -1:
+            fail("Target prefixes may only contain paths, not specific targets: %s" % prefix)
+
+        if prefix.startswith("@"):
+            if len(prefix) > 1:
+                path_prefixes.append("external/%s" % prefix[1:].replace("//", "/"))
+            else:
+                # Allow all external dependencies to be ignored
+                path_prefixes.append("external/")
+        elif prefix.startswith("//"):
+            if len(prefix) < 3:
+                fail("Prefixes for targets within this workspace must contain a path")
+            path_prefixes.append(prefix[2:])
+
+    # Now we have the prefixes, ensure that they do not end with a slash
+    return [path[:-1] if path.endswith("/") else path for path in path_prefixes]
+
+def _path_match(file, prefixes):
+    short_path = file.dirname[len(file.root.path) + 1:]
+
+    for prefix in prefixes:
+        if short_path.startswith(prefix):
+            return True
+    return False
+
 def _javadoc_impl(ctx):
+    path_prefixes = _get_prefix_strings(ctx.attr.third_party_prefixes)
     sources = []
+
     for dep in ctx.attr.deps:
-        sources.extend(dep[JavaInfo].source_jars)
+        dep_srcs = dep[JavaInfo].transitive_source_jars.to_list() if ctx.attr.transitive else dep[JavaInfo].source_jars
+        for jar in dep_srcs:
+            if not _path_match(jar, path_prefixes):
+                sources.append(jar)

     jar_file = ctx.actions.declare_file("%s.jar" % ctx.attr.name)

@@ -41,13 +74,23 @@ javadoc = rule(
             doc = """The java libraries to generate javadocs for.

           The source jars of each dep will be used to generate the javadocs.
-          Currently docs for transitive dependencies are not generated.
+          By default docs for transitive dependencies are not generated.
           """,
             mandatory = True,
             providers = [
                 [JavaInfo],
             ],
         ),
+        "transitive": attr.bool(
+            doc = "Whether to generate docs for transitive dependencies too.",
+            default = False,
+        ),
+        "third_party_prefixes": attr.string_list(
+            doc = """Label prefixes to exclude from javadoc generation. This designed
+            to allow merging of all first party javadocs into a single jar whilst not
+            including any javadocs for third party packages the code may depend on.""",
+            default = ["@maven//"],
+        ),
         "javadocopts": attr.string_list(
             doc = """javadoc options.
             Note sources and classpath are derived from the deps. Any additional