bazel: add test that forbids DO_NOT_DISTRIBUTE in //gerrit-pgm:pgm.

Change-Id: Idf4695294c34bbca157d104cfb6e708bac727473

gerrit-pgm/BUILD

@@ -1,5 +1,6 @@
 load('//tools/bzl:java.bzl', 'java_library2')
 load('//tools/bzl:junit.bzl', 'junit_tests')
+load('//tools/bzl:license.bzl', 'license_test')
 
 SRCS = 'src/main/java/com/google/gerrit/pgm/'
 RSRCS = 'src/main/resources/com/google/gerrit/pgm/'
@@ -160,3 +161,7 @@ junit_tests(
     '//lib/jgit/org.eclipse.jgit.junit:junit',
   ],
 )
+
+license_test(
+  name = "pgm_license_test",
+  target = ":pgm")

lib/BUILD

@@ -1,3 +1,7 @@
+exports_files([
+  "LICENSE-DO_NOT_DISTRIBUTE"
+])
+
 java_library(
   name = 'servlet-api-3_1',
   neverlink = 1,

tools/bzl/BUILD

@@ -1,2 +1,4 @@
 
-exports_files(["license-map.py"])
+exports_files([
+  "license-map.py",
+  "test_empty.sh"])

tools/bzl/license.bzl

@@ -20,3 +20,28 @@ def license_map(name, target):
         cmd = "python $(location //tools/bzl:license-map.py) $(location :%s.xml) > $@" % name,
         outs = [ name + ".txt",],
         tools = [ "//tools/bzl:license-map.py", name + ".xml"])
+
+def license_test(name, target):
+    """Generate XML for all targets that depend directly on a LICENSE file"""
+    txt = name + "-forbidden.txt"
+
+    # fully qualify target name.
+    if target[0] not in ":/":
+        target = ":" + target
+    if target[0] != "/":
+        target = "//" + PACKAGE_NAME + target
+
+    forbidden = "//lib:LICENSE-DO_NOT_DISTRIBUTE"
+    native.genquery(
+        name = txt,
+        scope = [ target, forbidden ],
+        # Find everything that depends on a license file, but remove
+        # the license files themselves from this list.
+        expression = 'rdeps(%s, "%s", 1) - rdeps(%s, "%s", 0)' % (target, forbidden, target, forbidden),
+    )
+    native.sh_test(
+        name = name,
+        srcs = [ "//tools/bzl:test_empty.sh" ],
+        args  = [ "$(location :%s)" % txt],
+        data = [ txt ],
+    )

tools/bzl/test_empty.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+if test -s $1
+then
+    echo "$1 not empty:"
+    cat $1
+    exit 1
+fi