From 3241d2cb171c127338d5b67e04d86042c1d5465c Mon Sep 17 00:00:00 2001
From: Matt Mackay <mattem@gmail.com>
Date: Wed, 1 Jun 2022 21:58:29 -0400
Subject: [PATCH] fix: symlink to python3 instead of python_real

---
 py/private/entry.tmpl.sh                |  5 ++---
 py/private/toolchain/autodetecting.bzl  | 12 ++++++++++++
 py/private/toolchain/python.sh          |  2 +-
 py/private/utils.bzl                    |  4 +++-
 py/tests/external-deps/expected_pathing |  2 +-
 5 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/py/private/entry.tmpl.sh b/py/private/entry.tmpl.sh
index 38f1a570..afe99676 100644
--- a/py/private/entry.tmpl.sh
+++ b/py/private/entry.tmpl.sh
@@ -81,7 +81,7 @@ ENTRYPOINT="$(rlocation {{BINARY_ENTRY_POINT}})"
 VENV_SOURCE="$(alocation $(rlocation {{VENV_SOURCE}}))"
 VENV_LOCATION="$(alocation ${RUNFILES_DIR}/{{VENV_NAME}})"
 VBIN_LOCATION="${VENV_LOCATION}/bin"
-VPYTHON="${VBIN_LOCATION}/python3 {{INTERPRETER_FLAGS}}"
+VPYTHON="${VBIN_LOCATION}/python {{INTERPRETER_FLAGS}}"
 
 mkdir "${VENV_LOCATION}" 2>/dev/null || true
 ln -snf "${VENV_SOURCE}/include" "${VENV_LOCATION}/include"
@@ -89,8 +89,7 @@ ln -snf "${VENV_SOURCE}/lib" "${VENV_LOCATION}/lib"
 
 mkdir "${VBIN_LOCATION}" 2>/dev/null || true
 ln -snf ${VENV_SOURCE}/bin/* "${VBIN_LOCATION}/"
-ln -snf "${PYTHON_LOCATION}" "${VBIN_LOCATION}/python3"
-ln -snf "${VBIN_LOCATION}/python3" "${VBIN_LOCATION}/python"
+ln -snf "${PYTHON_LOCATION}" "${VBIN_LOCATION}/python"
 
 echo "home = ${VBIN_LOCATION}" > "${VENV_LOCATION}/pyvenv.cfg"
 echo "include-system-site-packages = false" >> "${VENV_LOCATION}/pyvenv.cfg"
diff --git a/py/private/toolchain/autodetecting.bzl b/py/private/toolchain/autodetecting.bzl
index 6a632e2d..dc26f277 100644
--- a/py/private/toolchain/autodetecting.bzl
+++ b/py/private/toolchain/autodetecting.bzl
@@ -1,8 +1,20 @@
+load("//py/private:utils.bzl", "INTERPRETER_FLAGS")
+
 def _autodetecting_py_wrapper_impl(rctx):
     which_python = rctx.which("python3")
     if which_python == None:
         fail("Unable to locate 'python3' on the path")
 
+    # Check if `which_python` ends up being the final binary, or it's actually a wrapper itself.
+    exec_result = rctx.execute(
+        [which_python] + INTERPRETER_FLAGS + ["-c", "import sys; import os; print(os.path.realpath(sys.executable))"],
+    )
+
+    if exec_result.return_code == 0:
+        which_python = exec_result.stdout.strip()
+    else:
+        fail("Unable to verify Python executable at '%s'" % which_python, exec_result.stderr)
+
     rctx.template(
         "python.sh",
         rctx.attr._python_wrapper_tmpl,
diff --git a/py/private/toolchain/python.sh b/py/private/toolchain/python.sh
index 4675c73f..1105dcec 100755
--- a/py/private/toolchain/python.sh
+++ b/py/private/toolchain/python.sh
@@ -9,7 +9,7 @@ PYTHON_BIN="{{PYTHON_BIN}}"
 if [ -z "${VIRTUAL_ENV:-}" ]; then
   exec "${PYTHON_BIN}" "$@"
 else
-  PYTHON_REAL="${VIRTUAL_ENV}/bin/python_real"
+  PYTHON_REAL="${VIRTUAL_ENV}/bin/python3"
   ln -snf "${PYTHON_BIN}" "${PYTHON_REAL}"
   exec "${PYTHON_REAL}" "$@"
 fi
diff --git a/py/private/utils.bzl b/py/private/utils.bzl
index 5f893058..c522f658 100644
--- a/py/private/utils.bzl
+++ b/py/private/utils.bzl
@@ -1,6 +1,8 @@
 PY_TOOLCHAIN = "@bazel_tools//tools/python:toolchain_type"
 SH_TOOLCHAIN = "@bazel_tools//tools/sh:toolchain_type"
 
+INTERPRETER_FLAGS = ["-B", "-s", "-I"]
+
 def dict_to_exports(env):
     return [
         "export %s=\"%s\"" % (k, v)
@@ -35,5 +37,5 @@ def resolve_toolchain(ctx):
         files = files,
         python = interpreter,
         uses_interpreter_path = uses_interpreter_path,
-        flags = ["-B", "-s", "-I"],
+        flags = INTERPRETER_FLAGS,
     )
diff --git a/py/tests/external-deps/expected_pathing b/py/tests/external-deps/expected_pathing
index c87ffa58..637ec25f 100644
--- a/py/tests/external-deps/expected_pathing
+++ b/py/tests/external-deps/expected_pathing
@@ -1,4 +1,4 @@
-Python: (pwd)/bazel-out/host/bin/py/tests/external-deps/pathing.runfiles/pathing.venv/bin/python3
+Python: (pwd)/bazel-out/host/bin/py/tests/external-deps/pathing.runfiles/pathing.venv/bin/python
 version: 3.9.10 (main, REDACTED) 
 [Clang 13.0.1 ]
 version info: sys.version_info(major=3, minor=9, micro=10, releaselevel='final', serial=0)