From 4029dbdd5573c944a125ec3b7ad7db7986e01663 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Wed, 25 Jun 2025 16:28:25 -0700
Subject: [PATCH 1/3] add test

---
 tests/version/version_test.bzl | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/version/version_test.bzl b/tests/version/version_test.bzl
index 589f9ac05d..aa1a209fa4 100644
--- a/tests/version/version_test.bzl
+++ b/tests/version/version_test.bzl
@@ -105,6 +105,14 @@ def _test_normalization(env):
 
 _tests.append(_test_normalization)
 
+def _test_normalize_local(env):
+    # Verify a local with a [digit][non-digit] sequence parses ok
+    in_str = "0.1.0+brt.9e"
+    actual = version.normalize(in_str)
+    env.expect.that_str(actual).equals("xxx")
+
+_tests.append(_test_normalize_local)
+
 def _test_ordering(env):
     want = [
         # Taken from https://peps.python.org/pep-0440/#summary-of-permitted-suffixes-and-relative-ordering

From ba2d225f8fd6f2ea6f07995d6e5830cbb4af0737 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Sun, 6 Jul 2025 20:11:56 -0700
Subject: [PATCH 2/3] fix parsing

---
 python/private/version.bzl     | 49 ++++++++++++++++++++++++++++++----
 tests/version/version_test.bzl |  2 +-
 2 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/python/private/version.bzl b/python/private/version.bzl
index f98165d391..99261e46ad 100644
--- a/python/private/version.bzl
+++ b/python/private/version.bzl
@@ -44,7 +44,13 @@ def _in(reference):
     return lambda token: token in reference
 
 def _ctx(start):
-    return {"norm": "", "start": start}
+    """Creates a context, which is state for parsing (or sub-parsing)."""
+    return {
+        # The result value from parsing
+        "norm": "",
+        # Where in the parser's input string this context starts.
+        "start": start,
+    }
 
 def _open_context(self):
     """Open an new parsing ctx.
@@ -60,7 +66,16 @@ def _open_context(self):
     return self.contexts[-1]
 
 def _accept(self, key = None):
-    """Close the current ctx successfully and merge the results."""
+    """Close the current ctx successfully and merge the results.
+
+    Args:
+        self: {type}`Parser}
+        key: {type}`str | None` the key to store the result in
+            the most recent context. If not set, the key is "norm".
+
+    Returns:
+        {type}`bool` always True
+    """
     finished = self.contexts.pop()
     self.contexts[-1]["norm"] += finished["norm"]
     if key:
@@ -79,7 +94,14 @@ def _discard(self, key = None):
     return False
 
 def _new(input):
-    """Create a new normalizer"""
+    """Create a new parser
+
+    Args:
+        input: {type}`str` input to parse
+
+    Returns:
+        {type}`Parser` a struct for a parser object.
+    """
     self = struct(
         input = input,
         contexts = [_ctx(0)],
@@ -167,7 +189,7 @@ def accept_placeholder(parser):
     return parser.accept()
 
 def accept_digits(parser):
-    """Accept multiple digits (or placeholders).
+    """Accept multiple digits (or placeholders), up to a non-digit/placeholder.
 
     Args:
       parser: The normalizer.
@@ -275,7 +297,24 @@ def accept_separator_alnum(parser):
     Returns:
       whether a separator and an alphanumeric string were accepted.
     """
-    parser.open_context()
+
+    # Input is "0.1.0+brt.9e"
+    ctx = parser.open_context()
+
+    if not accept(parser, _in([".", "-", "_"]), "."):
+        return parser.discard()
+
+    if accept_alnum(parser):
+        # First character is separator; skip it.
+        value = ctx["norm"][1:]
+
+        # PEP 440: Integer Normalization
+        if value.isdigit():
+            value = str(int(value))
+            ctx["norm"] = ctx["norm"][0] + value
+        return parser.accept()
+
+    return parser.discard()
 
     # PEP 440: Local version segments
     if (
diff --git a/tests/version/version_test.bzl b/tests/version/version_test.bzl
index aa1a209fa4..7ddb6cc851 100644
--- a/tests/version/version_test.bzl
+++ b/tests/version/version_test.bzl
@@ -109,7 +109,7 @@ def _test_normalize_local(env):
     # Verify a local with a [digit][non-digit] sequence parses ok
     in_str = "0.1.0+brt.9e"
     actual = version.normalize(in_str)
-    env.expect.that_str(actual).equals("xxx")
+    env.expect.that_str(actual).equals(in_str)
 
 _tests.append(_test_normalize_local)
 

From a5be4c76dfaaf1471f1d4f5430e07d049de586b6 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Sun, 6 Jul 2025 20:23:52 -0700
Subject: [PATCH 3/3] format/lint

---
 python/private/version.bzl | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/python/private/version.bzl b/python/private/version.bzl
index 99261e46ad..8b5fef7b2a 100644
--- a/python/private/version.bzl
+++ b/python/private/version.bzl
@@ -297,10 +297,9 @@ def accept_separator_alnum(parser):
     Returns:
       whether a separator and an alphanumeric string were accepted.
     """
-
-    # Input is "0.1.0+brt.9e"
     ctx = parser.open_context()
 
+    # PEP 440: Local version segments
     if not accept(parser, _in([".", "-", "_"]), "."):
         return parser.discard()
 
@@ -316,15 +315,6 @@ def accept_separator_alnum(parser):
 
     return parser.discard()
 
-    # PEP 440: Local version segments
-    if (
-        accept(parser, _in([".", "-", "_"]), ".") and
-        (accept_digits(parser) or accept_alnum(parser))
-    ):
-        return parser.accept()
-
-    return parser.discard()
-
 def accept_separator_alnum_sequence(parser):
     """Accept a sequence of separator+alphanumeric.