diff --git a/java/com/google/gerrit/server/args4j/ObjectIdHandler.java b/java/com/google/gerrit/server/args4j/ObjectIdHandler.java
index aa8a958..3cad7ce 100644
--- a/java/com/google/gerrit/server/args4j/ObjectIdHandler.java
+++ b/java/com/google/gerrit/server/args4j/ObjectIdHandler.java
@@ -16,9 +16,11 @@
 
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
+import org.eclipse.jgit.errors.InvalidObjectIdException;
 import org.eclipse.jgit.lib.ObjectId;
 import org.kohsuke.args4j.CmdLineException;
 import org.kohsuke.args4j.CmdLineParser;
+import org.kohsuke.args4j.NamedOptionDef;
 import org.kohsuke.args4j.OptionDef;
 import org.kohsuke.args4j.spi.OptionHandler;
 import org.kohsuke.args4j.spi.Parameters;
@@ -37,7 +39,14 @@
   @Override
   public int parseArguments(Parameters params) throws CmdLineException {
     final String n = params.getParameter(0);
-    setter.addValue(ObjectId.fromString(n));
+    try {
+      setter.addValue(ObjectId.fromString(n));
+    } catch (InvalidObjectIdException e) {
+      throw new CmdLineException(
+          owner,
+          String.format("expected SHA1 for option %s: %s", ((NamedOptionDef) option).name(), n),
+          e);
+    }
     return 1;
   }
 
diff --git a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
index 08f65da..db53555 100644
--- a/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
+++ b/javatests/com/google/gerrit/acceptance/git/AbstractPushForReview.java
@@ -3061,6 +3061,12 @@
     assertThat(r.getChange().attentionSet()).isEmpty();
   }
 
+  @Test
+  public void pushWithInvalidBaseIsRejected() throws Exception {
+    PushOneCommit.Result r = pushTo("refs/for/master%base=invalid");
+    r.assertErrorStatus("expected SHA1 for option --base: invalid");
+  }
+
   private DraftInput newDraft(String path, int line, String message) {
     DraftInput d = new DraftInput();
     d.path = path;