From 9a1893760d4819492eef5ca959aa9200c64d5ff6 Mon Sep 17 00:00:00 2001
From: Tatlatat <hungdotmn@gmail.com>
Date: Tue, 2 Jun 2026 10:23:20 +0700
Subject: [PATCH] fix(cookbook): skip pip --user fallback inside virtualenvs
 (#388) (#889)
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The dependency-install fallback chain unconditionally ran
'pip install --user', which fails inside a virtualenv (and as root in
LXC/containers) with 'Can not perform a --user install. User site-packages
are not visible in this virtualenv.' — even though the function's docstring
already noted --user is invalid in venvs.

Guard the --user fallback with a venv check so it only runs outside a venv
(where --user is actually valid for PEP-668 system Pythons). Derive the venv
probe interpreter from the install command (python for 'pip', python3 for
'pip3'/'python3 -m pip') so the check runs in pip's own environment. System
PEP-668 installs keep the --user fallback; venv/LXC-root installs no longer
hit the --user error. Updated the unit test for the new chain.

Closes #388
---
 routes/cookbook_helpers.py     | 18 +++++++++++++++---
 tests/test_cookbook_helpers.py |  5 +++--
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/routes/cookbook_helpers.py b/routes/cookbook_helpers.py
index ffa2f0f..c646864 100644
--- a/routes/cookbook_helpers.py
+++ b/routes/cookbook_helpers.py
@@ -152,13 +152,25 @@ def _pip_install_fallback_chain(package: str, *, python_cmd: str = "python3 -m p
     """Build a bash pip install fallback chain.
 
     Try the active interpreter/environment first. `--user` is invalid inside
-    many venvs, so keep the user-site fallback for PEP-668 system Pythons only
-    after the venv-safe attempt has failed.
+    many venvs, so only attempt the --user fallback when NOT inside a venv.
     """
     upgrade_flag = " -U" if upgrade else ""
     base = f"{python_cmd} install -q{upgrade_flag} {package} 2>/dev/null"
     user = f"{python_cmd} install --user --break-system-packages -q{upgrade_flag} {package} 2>/dev/null"
-    return f"{base} || {user}"
+    # Derive the python executable for the venv detection check.
+    # Must use the same interpreter that pip belongs to; hardcoding
+    # python3 breaks when pip lives in a venv that only has "python".
+    if " -m pip" in python_cmd:
+        python_exe = python_cmd.replace(" -m pip", "")
+    elif python_cmd.strip() == "pip":
+        python_exe = "python"
+    elif python_cmd.strip() == "pip3":
+        python_exe = "python3"
+    else:
+        python_exe = "python3"
+    venv_check = f'{python_exe} -c "import sys; sys.exit(0 if sys.prefix != sys.base_prefix else 1)"'
+    # venv_check exits 0 (true) when IN a venv; --user is only valid outside one.
+    return f"{base} || {{ {venv_check} || {user}; }}"
 
 
 def _cached_model_scan_script(model_dirs: list[str] | None = None) -> str:
diff --git a/tests/test_cookbook_helpers.py b/tests/test_cookbook_helpers.py
index ef1b2a5..5ce6650 100644
--- a/tests/test_cookbook_helpers.py
+++ b/tests/test_cookbook_helpers.py
@@ -92,8 +92,9 @@ def test_pip_install_fallback_chain_prefers_venv_safe_install():
 def test_pip_install_fallback_chain_allows_custom_python_command():
     chain = _pip_install_fallback_chain("hf_transfer", python_cmd="pip", upgrade=False)
     assert chain == (
-        "pip install -q hf_transfer 2>/dev/null || "
-        "pip install --user --break-system-packages -q hf_transfer 2>/dev/null"
+        'pip install -q hf_transfer 2>/dev/null || { '
+        'python -c "import sys; sys.exit(0 if sys.prefix != sys.base_prefix else 1)"'
+        ' || pip install --user --break-system-packages -q hf_transfer 2>/dev/null; }'
     )