Give pom_dlineage.xml its own output directory, fixing #39

It shared target/classes with the root build and declares only one
source file, so its incremental-compile cleanup deleted every other
demo's .class files before failing on its own (separately documented)
compile error, breaking a working build with no clue why. Builds into
target-dlineage/ instead. Also ignore Claude Code artifacts.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012qPRpoD8exYRrUmbfXXWXj

Author: 2 people

.gitignore

@@ -57,7 +57,13 @@ rebel.xml
 
 # Maven target
 **/target
+target-dlineage
 
 *.iml
 
+# Claude Code
+CLAUDE.md
+.claude/
+.mcp.json
+
 

README.md

@@ -227,7 +227,7 @@ standalone lineage tool:
 ```bash
 mvn -f pom_dlineage.xml package
 
-java -cp "target/gsp_demo_java_dlineage-1.0-SNAPSHOT.jar:lib/*" \
+java -cp "target-dlineage/gsp_demo_java_dlineage-1.0-SNAPSHOT.jar:lib/*" \
      gudusoft.gsqlparser.demos.dlineage.DataFlowAnalyzer \
      /f demo.sql /o lineage.json /json /graph \
      /simpleShowRelationTypes fdd,fdr /filterRelationTypes fdd
@@ -236,6 +236,15 @@ java -cp "target/gsp_demo_java_dlineage-1.0-SNAPSHOT.jar:lib/*" \
 Other invocations it supports: `/t mssql`, `/t postgresql`, `/showER`,
 `/filterRelationTypes fdd`.
 
+`pom_dlineage.xml` builds into `target-dlineage/`, a directory of its own,
+rather than the root build's `target/`. It shares this repository's
+`${project.basedir}` with `pom.xml` and declares only one source file, so
+without a separate output directory the compiler plugin's incremental-build
+cleanup would delete every `.class` file the root build produced that isn't
+part of this smaller source set — wiping out a working root build before this
+one even reaches its own compile error below. See
+[#39](https://github.com/sqlparser/gsp_demo_java/issues/39).
+
 > **This build currently fails**, and did so before the trees were merged. It
 > pins `lib/gsqlparser-3.1.1.0.jar`, but `DataFlowAnalyzer` has moved on and now
 > calls `getOption().setTraceTablePosition(...)` and

pom_dlineage.xml

@@ -105,6 +105,15 @@
     </dependencies>
 
     <build>
+        <!-- This POM shares ${project.basedir} with the root pom.xml, so without
+             an explicit, separate output directory it also shares target/classes.
+             It declares only one source file (see the compiler <includes> below),
+             so the compiler plugin's incremental-compilation cleanup deletes every
+             .class file the root build produced that isn't part of this smaller
+             source set, before this build even reaches its own compile error.
+             That wipes out a working root build with no indication of why. See
+             https://github.com/sqlparser/gsp_demo_java/issues/39. -->
+        <directory>${project.basedir}/target-dlineage</directory>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>