From 9f4b67cec4d3a075c8fa94e507ccad6d80366667 Mon Sep 17 00:00:00 2001
From: Ruslan Kuprieiev <kupruser@gmail.com>
Date: Fri, 29 Sep 2023 00:10:44 +0300
Subject: [PATCH] site_cache_dir: use .dvc/tmp/btime and fallback to
 st_birthtime

This will ensure that we won't be using index cache if you delete your repo
and start/clone fresh.
---
 dvc/repo/__init__.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/dvc/repo/__init__.py b/dvc/repo/__init__.py
index 1ae65b006..fca9ecc5b 100644
--- a/dvc/repo/__init__.py
+++ b/dvc/repo/__init__.py
@@ -577,6 +577,26 @@ class Repo:
 
         return DVCFileSystem(repo=self, subrepos=self.subrepos, **self._fs_conf)
 
+    @cached_property
+    def _btime(self):
+        if not self.tmp_dir:
+            return None
+
+        # Not all python versions/filesystems/platforms provide creation
+        # time (st_birthtime, stx_btime, etc), so we use our own dummy
+        # file and its mtime instead.
+        path = os.path.join(self.tmp_dir, "btime")
+
+        try:
+            with open(path, "x"):  # pylint: disable=unspecified-encoding
+                pass
+        except FileNotFoundError:
+            return None
+        except FileExistsError:
+            pass
+
+        return os.path.getmtime(path)
+
     @cached_property
     def site_cache_dir(self) -> str:
         import getpass
@@ -611,10 +631,15 @@ class Repo:
         # of the token components are changed.
         salt = 0
 
+        # NOTE: This helps us avoid accidentally reusing cache for repositories
+        # that just happened to be at the same path as old deleted ones.
+        btime = self._btime or getattr(os.stat(root_dir), "st_birthtime", None)
+
         md5 = hashlib.md5(  # noqa: S324  # nosec B324, B303
             str(
                 (
                     root_dir,
+                    btime,
                     getpass.getuser(),
                     version_tuple[0],
                     salt,