chore: import upstream snapshot with attribution

dev/dev_stubs/__init__.py

@@ -0,0 +1,86 @@
+"""Credential-free dev/CI stubs for reviewing provider-gated MLflow UI.
+
+``run_dev_server.py --stub-providers <names>`` installs these before launching
+the dev server so features gated on external providers/credentials render
+without real keys, cost, or nondeterminism.
+
+- ``claude`` -- a fake ``claude`` CLI on PATH, satisfying the MLflow Assistant's
+  Claude Code provider auth probe (see ``claude_cli.py``).
+
+The CI ui-review bot passes the names a PR needs; locally, pass them yourself.
+"""
+
+from __future__ import annotations
+
+import os
+import shlex
+import shutil
+import sys
+import tempfile
+from dataclasses import dataclass, field
+from pathlib import Path
+
+_DEV_STUBS_DIR = Path(__file__).resolve().parent
+_CLAUDE_CLI = _DEV_STUBS_DIR / "claude_cli.py"
+
+
+@dataclass
+class StubResult:
+    """What a launcher must apply after installing stubs."""
+
+    path_prepend: list[Path] = field(default_factory=list)
+    cleanup_paths: list[Path] = field(default_factory=list)
+    messages: list[str] = field(default_factory=list)
+
+
+def _install_claude(result: StubResult) -> None:
+    """Stage a ``claude`` shim that runs the stub CLI with the current interpreter."""
+    shim_dir = Path(tempfile.mkdtemp(prefix="mlflow-dev-stub-bin-"))
+    shim = shim_dir / "claude"
+    # Use sys.executable (not a bare `python3`) so resolution doesn't depend on PATH.
+    # Quote both paths so the shim survives spaces in the interpreter or repo path.
+    interpreter = shlex.quote(sys.executable)
+    script = shlex.quote(str(_CLAUDE_CLI))
+    shim.write_text(f'#!/usr/bin/env bash\nexec {interpreter} {script} "$@"\n')
+    shim.chmod(0o755)
+    result.path_prepend.append(shim_dir)
+    result.cleanup_paths.append(shim_dir)
+    result.messages.append(f"Staged stub `claude` at {shim}")
+
+
+_INSTALLERS = {
+    "claude": _install_claude,
+}
+
+AVAILABLE_STUBS = tuple(_INSTALLERS)
+
+
+def _cleanup(result: StubResult) -> None:
+    """Remove whatever a (possibly partial) install staged, e.g. on failure."""
+    for path in result.cleanup_paths:
+        shutil.rmtree(path, ignore_errors=True)
+
+
+def install_stubs(names: list[str]) -> StubResult:
+    """Install the named stubs, returning PATH/cleanup changes for the caller to apply."""
+    if unknown := [n for n in names if n not in _INSTALLERS]:
+        raise ValueError(
+            f"Unknown stub(s): {', '.join(unknown)}. Available: {', '.join(AVAILABLE_STUBS)}"
+        )
+    result = StubResult()
+    try:
+        for name in names:
+            _INSTALLERS[name](result)
+    except BaseException:
+        # An installer failed partway; clean up what earlier ones staged before
+        # re-raising so we don't leak temp dirs.
+        _cleanup(result)
+        raise
+    return result
+
+
+def apply_to_environ(result: StubResult) -> None:
+    """Apply a StubResult's PATH prepend to ``os.environ`` in place."""
+    if result.path_prepend:
+        prepend = os.pathsep.join(str(p) for p in result.path_prepend)
+        os.environ["PATH"] = f"{prepend}{os.pathsep}{os.environ.get('PATH', '')}"