Fix Windows process launch failures with long executable paths

[Copilot]

Eclipse fails to launch processes when executable paths exceed Windows' 260-character MAX_PATH limit. The existing code only shortened working directories, not the executable path itself.

Changes

Core Fix (DebugPlugin.java)

• Added shortenWindowsCommandLine() to handle long paths in all command-line arguments
• Uses Windows GetShortPathName API via existing Win32Handler to convert to 8.3 format
• Applied to all process launch code paths: ProcessBuilder, Runtime.exec(), and ExecFactory delegation
• Windows-only, triggers when paths exceed 258 characters

Test Coverage (LaunchTests.java)

• Added testProcessLaunchWithLongExecutablePath()
• Creates 400+ character paths, copies executables, verifies successful launch
• Tests both merged and separate output modes

Example

Before this fix, launching a process would fail:

String[] cmd = new String[] {
    "C:\\very\\long\\path\\exceeding\\260\\characters\\...\\app.exe",
    "--arg"
};
DebugPlugin.exec(cmd, workDir, null, false); // IOException: path too long

After:

// Internally shortened to: C:\VERY~1\LONG~1\...\APP~1.EXE
DebugPlugin.exec(cmd, workDir, null, false); // Success

Technical Note

Cannot use \\?\ long path prefix as Java's process creation APIs reject it (JDK-8315405). Short path conversion is the most reliable workaround.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• repo.eclipse.org

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Scan the repository for native code that calls native windows API having problems with long path.

We are getting reports Eclipse is unable to launch processes with long path and suspect it could be something in our native code, e.g we do not use proper windows API to handle long path

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.