provision: Source virtualenv for login shells conditionally.

This commit conditionally adds the source command for
virtualenv in the user's bash profile only when the
system is virtualized.

Checking WSL_DISTRO_NAME in the env vars
is the cheapest option in case of checking
whether the system runs as WSL VM since
it is an in memory operation.
Hence it is checked for first in `is_wsl_instace`.

Fixes #15029.

tools/lib/provision_inner.py

@@ -9,7 +9,9 @@
 import argparse
 import glob
 import os
+import pwd
 import shutil
+import subprocess
 import sys
 
 ZULIP_PATH = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
@@ -91,6 +93,28 @@ def configure_rabbitmq_paths() -> list[str]:
     return paths
 
 
+def is_wsl_instance() -> bool:
+    if "WSL_DISTRO_NAME" in os.environ:
+        return True
+
+    with open("/proc/version") as file:
+        content = file.read().lower()
+        if "microsoft" in content:
+            return True
+
+    result = subprocess.run(["uname", "-r"], capture_output=True, text=True, check=True)
+    if "microsoft" in result.stdout.lower():
+        return True
+
+    return False
+
+
+def is_vagrant_or_digitalocean_instance() -> bool:
+    user_id = os.getuid()
+    user_name = pwd.getpwuid(user_id).pw_name
+    return user_name in ["vagrant", "zulipdev"]
+
+
 def setup_shell_profile(shell_profile: str) -> None:
     shell_profile_path = os.path.expanduser(shell_profile)
 
@@ -106,7 +130,9 @@ def setup_shell_profile(shell_profile: str) -> None:
                 shell_profile_file.writelines(command + "\n")
 
     source_activate_command = "source " + os.path.join(VENV_PATH, "bin", "activate")
-    write_command(source_activate_command)
+    # We want to activate the virtual environment for login shells only on virtualized systems.
+    if is_vagrant_or_digitalocean_instance() or is_wsl_instance():
+        write_command(source_activate_command)
     if os.path.exists("/srv/zulip"):
         write_command("cd /srv/zulip")