[bazel] Allow classifiers in maven coordinates

Author: shs96c

java/private/common.bzl

@@ -98,19 +98,22 @@ def combine_jars(ctx, singlejar, inputs, output):
 
 def explode_coordinates(coords):
     """Takes a maven coordinate and explodes it into a tuple of
-    (groupId, artifactId, version, type)
+    (groupId, artifactId, version, type, classifier)
     """
     if not coords:
         return None
 
     parts = coords.split(":")
     if len(parts) == 3:
-        return (parts[0], parts[1], parts[2], "jar")
+        return (parts[0], parts[1], parts[2], "jar", "jar")
     if len(parts) == 4:
         # Assume a buildr coordinate: groupId:artifactId:type:version
-        return (parts[0], parts[1], parts[3], parts[2])
+        return (parts[0], parts[1], parts[3], parts[2], "jar")
+    if len(parts) == 5:
+        # Assume groupId:artifactId:type:classifier:version
+        return (parts[0], parts[1], parts[4], parts[2], parts[3])
 
-    fail("Unparsed: %s" % coords)
+    fail("Unparsed: %s -> %s" % (coords, parts))
 
 def read_coordinates(tags):
     coordinates = []

java/private/pom.bzl

@@ -19,6 +19,13 @@ _TYPED_DEP = """    <dependency>
       <type>{3}</type>
     </dependency>"""
 
+_CLASSIFIER_DEP = """    <dependency>
+      <groupId>{0}</groupId>
+      <artifactId>{1}</artifactId>
+      <version>{2}</version>
+      <classifier>{4}</classifier>
+    </dependency>"""
+
 def _pom_file_impl(ctx):
     # Ensure the target has coordinates
     if not ctx.attr.target[MavenInfo].coordinates:
@@ -34,15 +41,19 @@ def _pom_file_impl(ctx):
         "{artifactId}": coordinates[1],
         "{version}": coordinates[2],
         "{type}": coordinates[3],
+        "{classifier}": coordinates[4],
     }
 
     deps = []
     for dep in sorted(info.maven_deps.to_list()):
         exploded = explode_coordinates(dep)
-        if (exploded[3] == "jar"):
+        if (exploded[4] != "jar"):
+            template = _CLASSIFIER_DEP
+        elif (exploded[3] == "jar"):
             template = _PLAIN_DEP
         else:
             template = _TYPED_DEP
+
         deps.append(template.format(*exploded))
     substitutions.update({"{dependencies}": "\n".join(deps)})