Auto-Compilation Breaks Maven Builds

Problem description:

"Build project automatically" (Settings > Build, Execution, Deployment > Compiler) states it "Works while not running / debugging". However, auto-compilation continues to write to target/classes during Maven builds (e.g. “running”) launched from the IDE terminal. This causes file contention — particularly severe on Windows/NTFS where deleted files enter a DELETE PENDING state that blocks recreation by other processes. Parallel Maven builds exacerbate the problem, but the issue is observed on sequential builds.

Steps to reproduce:

 1. Open a large multi-module Maven project in IntelliJ IDEA
 2. Enable "Build project automatically" in Settings > Compiler
 3. Start a parallel Maven build from the IDE terminal (e.g. mvn clean install -T1C)
 4. Observe via Process Monitor (ProcMon) that JPS builders fire during the Maven build, deleting and rewriting files in target/classes
 5. Maven fails intermittently with errors such as "could not create parent directories", "Access Denied", or "NAME NOT FOUND"
 6. Disabling "Build project automatically" eliminates the failures (tested: 0/10 failures with auto-build OFF vs 2-4/10 with auto-build ON)

Expected behaviour: 

Auto-compilation should pause while a build/run process is active, as the setting description implies.

Actual behaviour: 

JPS file watcher detects Maven's changes in target/, dispatches JPS builders which delete and recompile target/classes concurrently with the running Maven build. The “Delegate IDE build/run actions to Maven” setting does NOT suppress auto-make (consistent with IDEA-228279).

Environment:

• OS: Windows 11 Enterprise 25H2 26200.8390
• JDK: AmazonCorretto 17
• Build tool: Maven IDE plugin (parallel build, -T1C)
• Project: Large multi-module Java/Jakarta EE project (~50+ modules)