Fix handling of packages without javadoc or sources

sync/generate-gradle.py

@@ -374,7 +374,9 @@ repositories {
 
 val deps = listOf(
     """ + ',\n    '.join(f'"{dep}"' for dep in sorted(packages)) + """
-).map {
+).flatMap {
+    listOf(it, it + ":sources", it + ":javadoc")
+}.map {
     configurations.create(it.replace(':', '_')) to it
 }
 
@@ -382,15 +384,25 @@ val deps = listOf(
 dependencies {
     deps.forEach { (conf, dep) ->
         conf(dep)
-        conf(dep + ":sources")
-        conf(dep + ":javadoc")
     }
 }
 
 tasks.register("downloadDependencies") {
+    val logger = getLogger()
+
     doLast {
-        deps.forEach { (conf, _) ->
-            conf.files
+        deps.forEach { (conf, dep) ->
+            try {
+                conf.files
+            } catch (e: Exception) {
+                if (dep.endsWith(":sources")) {
+                    logger.info("Package '$dep' has no sources")
+                } else if (dep.endsWith(":javadoc")) {
+                    logger.info("Package '$dep' has no javadoc")
+                } else {
+                    logger.warn("Error while fetching '$dep': $e")
+                }
+            }
         }
     }
 }