From 6b446abe4ba17b4619b3e27b295491479dc58fa6 Mon Sep 17 00:00:00 2001
From: Luis Pineda <4759586+luisenp@users.noreply.github.com>
Date: Fri, 7 Jul 2023 18:18:40 -0400
Subject: [PATCH] Removed semantic version dependency. (#574)

* Removed semantic version dependency.

* Fix mypy error for Python <= 3.8.

* Add missing copyright header.
---
 tests/theseus_tests/test_misc.py | 19 +++++++++++++++++++
 theseus/_version.py              | 25 ++++++++++++++++++++++---
 theseus/third_party/lml.py       |  7 +++----
 3 files changed, 44 insertions(+), 7 deletions(-)
 create mode 100644 tests/theseus_tests/test_misc.py

diff --git a/tests/theseus_tests/test_misc.py b/tests/theseus_tests/test_misc.py
new file mode 100644
index 00000000..179bd7e3
--- /dev/null
+++ b/tests/theseus_tests/test_misc.py
@@ -0,0 +1,19 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+import pytest
+
+from theseus._version import lt_version
+
+
+def test_lt_version():
+    assert not lt_version("2.0.0", "0.4.0")
+    assert not lt_version("1.13.0abcd", "0.4.0")
+    assert not lt_version("0.4.1+yzx", "0.4.0")
+    assert lt_version("1.13.0.1.2.3.4", "2.0.0")
+    assert lt_version("1.13.0.1.2+abc", "2.0.0")
+    with pytest.raises(ValueError):
+        lt_version("1.2", "0.4.0")
+        lt_version("1", "0.4.0")
+        lt_version("1.", "0.4.0")
diff --git a/theseus/_version.py b/theseus/_version.py
index cbcd4953..ebe694a4 100644
--- a/theseus/_version.py
+++ b/theseus/_version.py
@@ -2,12 +2,31 @@
 #
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
+import re
 import warnings
+from typing import Tuple
 
-from semantic_version import Version
-from torch import __version__ as _torch_version
+import torch
 
-if Version(_torch_version) < Version("2.0.0"):
+
+# Returns True/False if version string v1 is less than version string v2
+def lt_version(v1: str, v2: str) -> bool:
+    def _as_tuple(s: str) -> Tuple[int, int, int]:
+        pattern = r"^[\d.]+"
+        match = re.match(pattern, s)
+        try:
+            return tuple(int(x) for x in match.group().split(".")[:3])  # type: ignore
+        except Exception:
+            raise ValueError(
+                f"String {s} cannot be converted to (mayor, minor, micro) format."
+            )
+
+    x1, y1, z1 = _as_tuple(v1)
+    x2, y2, z2 = _as_tuple(v2)
+    return x1 < x2 or (x1 == x2 and y1 < y2) or (x1 == x2 and y1 == y2 and z1 < z2)
+
+
+if lt_version(torch.__version__, "2.0.0"):
     warnings.warn(
         "Using torch < 2.0 for theseus is deprecated and compatibility will be "
         "discontinued in future releases.",
diff --git a/theseus/third_party/lml.py b/theseus/third_party/lml.py
index 300aaee1..b4d4b05f 100755
--- a/theseus/third_party/lml.py
+++ b/theseus/third_party/lml.py
@@ -20,16 +20,15 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
 import numpy as np
 import numpy.random as npr
 import torch
-from semantic_version import Version
 from torch.autograd import Function, Variable, grad
 from torch.nn import Module
 
-version = Version(".".join(torch.__version__.split(".")[:3]))
-old_torch = version < Version("0.4.0")
+from theseus._version import lt_version
+
+old_torch = lt_version(torch.__version__, "0.4.0")
 
 
 def bdot(x, y):