Fix NPE with unset maven_jar sha1

Fixes #1537.

--
MOS_MIGRATED_REVID=127945452

3 files changed, 17 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java
index 8e2693b4ad..28c4a00dcc 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java
@@ -180,8 +180,9 @@ public class MavenJarFunction extends HttpArchiveFunction {
       this.outputDirectory = outputDirectory;
 
       this.artifact = mapper.get("artifact", Type.STRING);
-      this.sha1 = (mapper.has("sha1", Type.STRING)) ? mapper.get("sha1", Type.STRING) : null;
-      if (!sha1.matches("\\p{XDigit}{40}")) {
+      this.sha1 = mapper.isAttributeValueExplicitlySpecified("sha1")
+          ? mapper.get("sha1", Type.STRING) : null;
+      if (sha1 != null && !sha1.matches("\\p{XDigit}{40}")) {
         throw new IOException("Invalid SHA-1 for maven_jar " + name + ": '" + sha1 + "'");
       }
       this.url = serverValue.getUrl();
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunctionTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunctionTest.java
index 916546330d..6ad732e9d7 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunctionTest.java
@@ -65,4 +65,15 @@ public class MavenJarFunctionTest extends BuildViewTestCase {
     AggregatingAttributeMapper map = AggregatingAttributeMapper.of(rule);
     new MavenDownloader("foo", map, scratch.dir("/whatever"), TEST_SERVER);
   }
+
+  @Test
+  public void testNoSha1() throws Exception {
+    Rule rule = scratchRule("external", "foo",
+        "maven_jar(",
+        "    name = 'foo',",
+        "    artifact = 'x',",
+        ")");
+    AggregatingAttributeMapper map = AggregatingAttributeMapper.of(rule);
+    new MavenDownloader("foo", map, scratch.dir("/whatever"), TEST_SERVER);
+  }
 }
diff --git a/src/test/shell/bazel/maven_test.sh b/src/test/shell/bazel/maven_test.sh
index 48d60f36fb..c3d9293a33 100755
--- a/src/test/shell/bazel/maven_test.sh
+++ b/src/test/shell/bazel/maven_test.sh
@@ -114,19 +114,20 @@ function test_maven_jar_mismatched_sha1() {
   setup_zoo
   serve_jar
 
+  wrong_sha1="0123456789012345678901234567890123456789"
   cat > WORKSPACE <<EOF
 maven_jar(
     name = 'endangered',
     artifact = "com.example.carnivore:carnivore:1.23",
     repository = 'http://localhost:$nc_port/',
-    sha1 = '$sha256',
+    sha1 = '$wrong_sha1',
 )
 bind(name = 'mongoose', actual = '@endangered//jar')
 EOF
 
   bazel fetch //zoo:ball-pit >& $TEST_log && echo "Expected fetch to fail"
   kill_nc
-  expect_log "has SHA-1 of $sha1, does not match expected SHA-1 ($sha256)"
+  expect_log "has SHA-1 of $sha1, does not match expected SHA-1 ($wrong_sha1)"
 }
 
 function test_default_repository() {