chore: import upstream snapshot with attribution

tests/go_client/scripts/install_external_table_python_deps.sh

@@ -0,0 +1,80 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
+GO_CLIENT_DIR="$(cd -- "${SCRIPT_DIR}/.." >/dev/null 2>&1 && pwd)"
+REQUIREMENTS="${GO_CLIENT_DIR}/requirements.txt"
+PYTHON_BIN="${PYTHON_BIN:-python3}"
+
+ensure_python() {
+    if command -v "${PYTHON_BIN}" >/dev/null 2>&1; then
+        return
+    fi
+    if command -v apt-get >/dev/null 2>&1 && [ "$(id -u)" = "0" ]; then
+        apt-get update
+        apt-get install -y --no-install-recommends python3 python3-pip
+        return
+    fi
+    echo "${PYTHON_BIN} is not available and cannot be installed automatically" >&2
+    exit 1
+}
+
+ensure_pip() {
+    if "${PYTHON_BIN}" -m pip --version >/dev/null 2>&1; then
+        return
+    fi
+    if command -v apt-get >/dev/null 2>&1 && [ "$(id -u)" = "0" ]; then
+        apt-get update
+        apt-get install -y --no-install-recommends python3-pip
+        return
+    fi
+    echo "pip is not available for ${PYTHON_BIN}" >&2
+    exit 1
+}
+
+check_deps() {
+    "${PYTHON_BIN}" - <<'PY'
+import importlib
+import sys
+
+missing = []
+for module in ("pyarrow", "pyiceberg", "vortex", "obstore", "substrait"):
+    try:
+        importlib.import_module(module)
+    except Exception:
+        missing.append(module)
+
+try:
+    lance = importlib.import_module("lance")
+    if not hasattr(lance, "write_dataset"):
+        missing.append("pylance (lance.write_dataset)")
+except Exception:
+    missing.append("pylance")
+
+if missing:
+    print("missing python packages: " + ", ".join(missing))
+    sys.exit(1)
+PY
+}
+
+install_deps() {
+    # The unrelated PyPI package named "lance" shadows pylance's "lance"
+    # module but does not provide write_dataset.
+    "${PYTHON_BIN}" -m pip uninstall -y lance >/dev/null 2>&1 || true
+    if ! "${PYTHON_BIN}" -m pip install \
+        --no-cache-dir --break-system-packages -r "${REQUIREMENTS}"; then
+        "${PYTHON_BIN}" -m pip install --no-cache-dir -r "${REQUIREMENTS}"
+    fi
+}
+
+ensure_python
+ensure_pip
+
+if check_deps; then
+    echo "external table python deps already installed"
+    exit 0
+fi
+
+echo "installing external table python deps from ${REQUIREMENTS}"
+install_deps
+check_deps