feat: enhance console output handling in run_flow script

.gitignore

@@ -11,6 +11,7 @@
 *.ddb
 *.fst
 *.txt
+*.demo
 !requirements/
 !requirements/*.txt
 *.gtkw

scripts/run_flow.py

@@ -8,6 +8,7 @@ import os
 import re
 import subprocess
 import sys
+import termios
 import time
 from datetime import datetime, timezone
 from pathlib import Path
@@ -47,6 +48,23 @@ def jobserver_fds() -> tuple[int, ...]:
     return descriptors
 
 
+def terminal_requires_crlf() -> bool:
+    if not sys.stdout.isatty():
+        return False
+    try:
+        output_flags = termios.tcgetattr(sys.stdout.fileno())[1]
+    except OSError:
+        return False
+    return not (output_flags & termios.OPOST and output_flags & termios.ONLCR)
+
+
+def write_console_output(line: str) -> None:
+    if terminal_requires_crlf():
+        line = line.replace("\n", "\r\n")
+    sys.stdout.write(line)
+    sys.stdout.flush()
+
+
 def main() -> int:
     parser = argparse.ArgumentParser(description="Run a flow command with structured results")
     parser.add_argument("--tool", required=True)
@@ -89,8 +107,7 @@ def main() -> int:
                 log.write(line)
                 log.flush()
                 if should_display(args.tool, line):
-                    sys.stdout.write(line)
-                    sys.stdout.flush()
+                    write_console_output(line)
             returncode = process.wait()
     except KeyboardInterrupt:
         error_message = "interrupted"

tests/test_script_tools.py

@@ -38,6 +38,7 @@ from scripts.generate_mpw import (  # noqa: E402
 )
 from scripts.install_toolchain import safe_extract  # noqa: E402
 from scripts import regress  # noqa: E402
+from scripts import run_flow  # noqa: E402
 from scripts.regress import (  # noqa: E402
     NIGHTLY_COMMANDS,
     PDK_PR_PROFILES,
@@ -802,6 +803,48 @@ def test_run_flow_writes_structured_result(tmp_path: Path) -> None:
     assert log.read_text(encoding="utf-8") == "flow output\n"
 
 
+def test_run_flow_adds_carriage_return_when_terminal_disables_onlcr(monkeypatch) -> None:
+    class Terminal(io.StringIO):
+        def isatty(self) -> bool:
+            return True
+
+        def fileno(self) -> int:
+            return 42
+
+    terminal = Terminal()
+    monkeypatch.setattr(run_flow.sys, "stdout", terminal)
+    monkeypatch.setattr(
+        run_flow.termios,
+        "tcgetattr",
+        lambda descriptor: [0, run_flow.termios.OPOST, 0, 0, 0, 0, 0],
+    )
+
+    run_flow.write_console_output("first\nsecond\n")
+
+    assert terminal.getvalue() == "first\r\nsecond\r\n"
+
+
+def test_run_flow_keeps_newlines_when_terminal_maps_them_to_carriage_return(monkeypatch) -> None:
+    class Terminal(io.StringIO):
+        def isatty(self) -> bool:
+            return True
+
+        def fileno(self) -> int:
+            return 42
+
+    terminal = Terminal()
+    monkeypatch.setattr(run_flow.sys, "stdout", terminal)
+    monkeypatch.setattr(
+        run_flow.termios,
+        "tcgetattr",
+        lambda descriptor: [0, run_flow.termios.OPOST | run_flow.termios.ONLCR, 0, 0, 0, 0, 0],
+    )
+
+    run_flow.write_console_output("first\nsecond\n")
+
+    assert terminal.getvalue() == "first\nsecond\n"
+
+
 def test_run_flow_records_interruption(tmp_path: Path) -> None:
     log = tmp_path / "interrupted.log"
     result = tmp_path / "interrupted.json"