Exclude .g4 files under spark from repository

spark/build.gradle

@@ -14,22 +14,47 @@ repositories {
     mavenCentral()
 }
 
-tasks.register('downloadG4Files', Exec) {
+tasks.register('downloadG4Files') {
     description = 'Download remote .g4 files from GitHub'
 
-    executable 'curl'
+    // use doLast to wait the completion of command execution
+    doLast {
+        project.exec {
+            executable 'curl'
 
-    args '-o', 'src/main/antlr/FlintSparkSqlExtensions.g4', 'https://raw.githubusercontent.com/opensearch-project/opensearch-spark/main/flint-spark-integration/src/main/antlr4/FlintSparkSqlExtensions.g4'
-    args '-o', 'src/main/antlr/SparkSqlBase.g4', 'https://raw.githubusercontent.com/opensearch-project/opensearch-spark/main/flint-spark-integration/src/main/antlr4/SparkSqlBase.g4'
-    args '-o', 'src/main/antlr/SqlBaseParser.g4', 'https://raw.githubusercontent.com/apache/spark/master/sql/api/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBaseParser.g4'
-    args '-o', 'src/main/antlr/SqlBaseLexer.g4', 'https://raw.githubusercontent.com/apache/spark/master/sql/api/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBaseLexer.g4'
+            args '-o', 'src/main/antlr/FlintSparkSqlExtensions.g4', 'https://raw.githubusercontent.com/opensearch-project/opensearch-spark/main/flint-spark-integration/src/main/antlr4/FlintSparkSqlExtensions.g4'
+            args '-o', 'src/main/antlr/SparkSqlBase.g4', 'https://raw.githubusercontent.com/opensearch-project/opensearch-spark/main/flint-spark-integration/src/main/antlr4/SparkSqlBase.g4'
+            args '-o', 'src/main/antlr/SqlBaseParser.g4', 'https://raw.githubusercontent.com/apache/spark/master/sql/api/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBaseParser.g4'
+            args '-o', 'src/main/antlr/SqlBaseLexer.g4', 'https://raw.githubusercontent.com/apache/spark/master/sql/api/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBaseLexer.g4'
+        }
+        project.exec {
+            executable 'ls'
+
+            args '-l', 'src/main/antlr/'
+        }
+    }
 }
+clean.delete fileTree('src/main/antlr/') { include '*.g4' }
 
 generateGrammarSource {
     arguments += ['-visitor', '-package', 'org.opensearch.sql.spark.antlr.parser']
     source = sourceSets.main.antlr
     outputDirectory = file("build/generated-src/antlr/main/org/opensearch/sql/spark/antlr/parser")
 }
+tasks.register('checkGrammarSource') {
+    description = 'temporal'
+
+    doLast {
+        project.exec {
+            executable 'ls'
+
+            args '-l', 'build/generated-src/antlr/main/org/opensearch/sql/spark/antlr/parser'
+        }
+    }
+}
+checkGrammarSource.dependsOn generateGrammarSource
+compileJava.dependsOn checkGrammarSource
+
 configurations {
     compile {
         extendsFrom = extendsFrom.findAll { it != configurations.antlr }

spark/src/main/antlr/.gitignore

@@ -0,0 +1,2 @@
+# .g4 files are downloaded from other repositories during build
+*.g4