Support for multi-file source launcher causes regressions for normal projects

[matthiasblaesing]

Body

I noticed, that when I created a test.java file in my tmp directory, NetBeans suddenly started a massive scanning job. It turned out NetBeans scanned the whole folder, which also included an angular project with ~30.000 files in the node_modules folder. What is more, I noticed, that other projects in the folder were marked as broken.

My gut feeling led me to the changes for the mult-file source launcher and indeed it has problematic side effect. I could reproduce it like this:

0. Checkout babcc3d (current master), clean dir and build NB and run with "ant tryme"

1. Create an empty directory (PATH in the following)

2. Inside the new directory create a new maven project ("Java with Maven -> Java Application", with default settings, just parent folder changed to PATH)

3. Add gson to the pom.xml (as child element of the project node):

   <dependencies>
       <dependency>
           <groupId>com.google.code.gson</groupId>
           <artifactId>gson</artifactId>
           <version>2.10.1</version>
       </dependency>
   </dependencies>

4. Ensure dependency is locally present by invoking "Download Declared Dependencies" on the "Dependencies" node

5. Change class Mavenproject1 to:

   package test.mavenproject1;
   
   import com.google.gson.Gson;
   import java.util.Collections;
   
   public class Mavenproject1 {
   
       public static void main(String[] args) {
   	new Gson().toJson(Collections.singletonMap("Hello", "World"));
       }
   }

6. Open Favorites tab and create test.java in the directory created in step 1

Mavenproject1.java is immediately marked as "has errors

9. Open "Window -> Action Items" and open Mavenproject1.java

You'll see:

Error	Package com.google.gson ist nicht vorhanden	Mavenproject1.java	PATH/mavenproject1/src/main/java/test/mavenproject1/Mavenproject1.java:3
Error	Symbol nicht gefunden   Symbol: Klasse Gson   Ort: Klasse test.mavenproject1.Mavenproject1	Mavenproject1.java	PATH/mavenproject1/src/main/java/test/mavenproject1/Mavenproject1.java:9

10. Remove the directory
11. Revert multi-file launcher:

 git revert 192bb526a9f535485905998674460c1aaafb9b20
 git rm java/java.file.launcher/src/org/netbeans/modules/java/file/launcher/SharedRootData.java java/java.file.launcher/src/org/netbeans/modules/java/file/launcher/queries/MultiSourceRootProvider.java
 git revert --continue

13. Build again with git clean -f -x -d; ant
14. Run with ant try
15. Repeat steps 2-7 and observe, that problems are gone

Committer

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[lahodaj]

Sorry, I was off for a winter break. I've opened:
#6912

[mbien]

related issue #6921, regression in the amount of indexing NB does during regular maven project creation.