[3.13] gh-119132: Update sys.version to identify free-threaded or not. (gh-119134) (#119153)

gh-119132: Update sys.version to identify free-threaded or not. (gh-119134)
(cherry picked from commit c141d4393750c827cbcb3867f0f42997a3bb3528)

Co-authored-by: Donghee Na <donghee.na@python.org>
diff --git a/Lib/platform.py b/Lib/platform.py
index ebaba37..5958382 100755
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -1153,17 +1153,16 @@ def _sys_version(sys_version=None):
     if result is not None:
         return result
 
-    sys_version_parser = re.compile(
-        r'([\w.+]+)\s*'  # "version<space>"
-        r'\(#?([^,]+)'  # "(#buildno"
-        r'(?:,\s*([\w ]*)'  # ", builddate"
-        r'(?:,\s*([\w :]*))?)?\)\s*'  # ", buildtime)<space>"
-        r'\[([^\]]+)\]?', re.ASCII)  # "[compiler]"
-
     if sys.platform.startswith('java'):
         # Jython
+        jython_sys_version_parser = re.compile(
+            r'([\w.+]+)\s*'  # "version<space>"
+            r'\(#?([^,]+)'  # "(#buildno"
+            r'(?:,\s*([\w ]*)'  # ", builddate"
+            r'(?:,\s*([\w :]*))?)?\)\s*'  # ", buildtime)<space>"
+            r'\[([^\]]+)\]?', re.ASCII)  # "[compiler]"
         name = 'Jython'
-        match = sys_version_parser.match(sys_version)
+        match = jython_sys_version_parser.match(sys_version)
         if match is None:
             raise ValueError(
                 'failed to parse Jython sys.version: %s' %
@@ -1190,7 +1189,14 @@ def _sys_version(sys_version=None):
 
     else:
         # CPython
-        match = sys_version_parser.match(sys_version)
+        cpython_sys_version_parser = re.compile(
+            r'([\w.+]+)\s*'  # "version<space>"
+            r'(?:experimental free-threading build\s+)?' # "free-threading-build<space>"
+            r'\(#?([^,]+)'  # "(#buildno"
+            r'(?:,\s*([\w ]*)'  # ", builddate"
+            r'(?:,\s*([\w :]*))?)?\)\s*'  # ", buildtime)<space>"
+            r'\[([^\]]+)\]?', re.ASCII)  # "[compiler]"
+        match = cpython_sys_version_parser.match(sys_version)
         if match is None:
             raise ValueError(
                 'failed to parse CPython sys.version: %s' %
diff --git a/Misc/NEWS.d/next/Build/2024-05-17-19-53-27.gh-issue-119132.wepPgM.rst b/Misc/NEWS.d/next/Build/2024-05-17-19-53-27.gh-issue-119132.wepPgM.rst
new file mode 100644
index 0000000..44fe2a1
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2024-05-17-19-53-27.gh-issue-119132.wepPgM.rst
@@ -0,0 +1,2 @@
+Update :data:`sys.version` to identify whether the build is default build or
+free-threading build. Patch By Donghee Na.
diff --git a/Python/getversion.c b/Python/getversion.c
index 5db836a..226b2f9 100644
--- a/Python/getversion.c
+++ b/Python/getversion.c
@@ -6,7 +6,7 @@
 #include "patchlevel.h"
 
 static int initialized = 0;
-static char version[250];
+static char version[300];
 
 void _Py_InitVersion(void)
 {
@@ -14,7 +14,12 @@ void _Py_InitVersion(void)
         return;
     }
     initialized = 1;
-    PyOS_snprintf(version, sizeof(version), "%.80s (%.80s) %.80s",
+#ifdef Py_GIL_DISABLED
+    const char *buildinfo_format = "%.80s experimental free-threading build (%.80s) %.80s";
+#else
+    const char *buildinfo_format = "%.80s (%.80s) %.80s";
+#endif
+    PyOS_snprintf(version, sizeof(version), buildinfo_format,
                   PY_VERSION, Py_GetBuildInfo(), Py_GetCompiler());
 }