processFileChanges method in DevUtil (ci.common) runs twice with a single file change

[TrevCraw]

The method processFileChanges is running twice when a single modification is made to a file while running maven dev mode (have not yet confirmed if this happens in gradle or not). So far, this has been tested by making file modifications in IntelliJ, Notepad++, and Notepad. Notepad did NOT cause the method to run twice, but both IntelliJ and Notepad++ did.

Processing file changes for C:\Users\TREVORCrawford\Git\demo-devmode\src\test.properties, change type MODIFY
Processing file changes for C:\Users\TREVORCrawford\Git\demo-devmode\src\test.properties, change type MODIFY

[sajeerzeji]

As the issue described, the processFileChanges is not running twice now for the properties file inside src directory. In this case, right now as I checked, processFileChanges is not even running once, this is because src root directory is NOT monitored by the file watching system.

Monitored Directories:

• src/main/java (registered at line 2974 in DevUtil.java)
• src/test/java (registered at line 2980)
• src/main/resources (registered at line 3016)
• src/main/liberty/config (registered at line 2985)

However, I did an extended testing on this one and found below cases

1. Changes to a properties file inside src/main/resources/ is running processFileChanges twice.

This is because in this case, both source and target directories are monitored, causing duplicate detection like below

First Detection - Source File

• WatchService detects modification on src/main/resources/test.properties
• It called processFileChanges()
• This matches the condition like resourceParent != null
• And then resourceModifiedOrCreated() method gets called, which triggers maven resources plugin
• Maven copies file to target/classes/test.properties
• Hot reload happens, with no re compilation

Second Detection - Target File

• WatchService detects modification on target/classes/test.properties
• It called processFileChanges() again
• resourceParent check returns NULL because target/classes is not in resourceDirs list
• No other actions
• No hot reload

2. Changes to a properties file inside src/main/liberty/config/ is running processFileChanges only once

This is because when bootstrap.properties changes, it matches the configPath condition and calls processConfigFileChange(), which copies the file to the Liberty server and restarts. In this case only the source directory is monitored. The Liberty server target directory is intentionally not monitored, avoiding duplicate detection.

3. Java file changes triggers multiple processFileChanges() calls

In this case, it sometimes triggers it more than two time but recompiles only once, this is because of some logics in detecting class file changes, we need to do a deep investigation on this to find out why it is happening.

CC: @venmanyarun

[sajeerzeji]

The mentioned issue has been fixed at this PR OpenLiberty/ci.common#505

Tested with .properties file

Tested with java file