decode process output streams using the native encoding

[netliomax25-code]

1. getText(Process) and TextDumper (which backs consumeProcessOutput, waitForProcessOutput and the new waitForResult/ProcessResult) decode the process output stream through new InputStreamReader(stream) with no charset, so they use Charset.defaultCharset().
2. since JEP 400 that default is UTF-8 regardless of platform, while a child process still writes its output in the OS native encoding, so on a non-UTF-8 host (a Windows code page, or Linux under a C/legacy locale) non-ASCII output no longer round-trips and is silently corrupted (a native 0xE9 byte for é decodes to U+FFFD).

Decode with the native.encoding system property (JDK 17+, the documented way to obtain the OS native encoding), falling back to Charset.defaultCharset() when it is unavailable. UTF-8 hosts are unaffected.

[Copilot]

Pull request overview

This PR updates Groovy’s process I/O helpers to decode child process output using the OS native encoding (via the native.encoding system property) instead of relying on Charset.defaultCharset(), avoiding silent character corruption on non-UTF-8 hosts post–JEP 400.

Changes:

• Add a nativeEncoding() helper that resolves System.getProperty("native.encoding") with fallback to Charset.defaultCharset().
• Use nativeEncoding() when decoding Process#getInputStream() in getText(Process).
• Use nativeEncoding() in TextDumper (used by consumeProcessOutput* / waitForProcessOutput* pathways) when reading process output.

Comments suppressed due to low confidence (1)

src/main/java/org/codehaus/groovy/runtime/ProcessGroovyMethods.java:658

• TextDumper creates BufferedReader/InputStreamReader but never closes it, so the underlying process stream can remain open if the thread exits early (e.g., due to an exception). Wrapping the reader in try-with-resources ensures the stream is always closed and avoids resource leaks.

            InputStreamReader isr = new InputStreamReader(in, nativeEncoding());
            BufferedReader br = new BufferedReader(isr);
            String next;
            try {
                while ((next = br.readLine()) != null) {

[testlens-app]

✅ All tests passed ✅

🏷️ Commit: 913be1a
▶️ Tests: 103404 executed
⚪️ Checks: 23/23 completed

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