stable-25-3-1: Fix segfault in version parser (#25714)

Author: ydbot

ydb/core/driver_lib/version/ut/version_ut.cpp

@@ -189,6 +189,19 @@ Y_UNIT_TEST_SUITE(YdbVersion) {
                 false
         );
     }
+    Y_UNIT_TEST(DefaulPatchTag) {
+        Test(
+                TCurrentCompatibilityInfo{
+                    .Application = "ydb",
+                    .Version = TVersion{ .Year = 25, .Major = 1, .Minor = 14 }
+                }, 
+                TCurrentCompatibilityInfo{
+                    .Application = "ydb",
+                    .Version = TVersion{ .Year = 25, .Major = 1, .Minor = 15, .Patch = 1 }
+                }, 
+                true
+        );
+    }
     Y_UNIT_TEST(LimitOld) {
         Test(
                 TCurrentCompatibilityInfo{

ydb/core/driver_lib/version/version.cpp

@@ -429,7 +429,7 @@ std::optional<NKikimrConfig::TYdbVersion> ParseVersionFromTag(TString tag, TStri
 
     if (parts.empty()) {
         // example: stable-22-1 == 22.1
-        // major version, from which minor tags are formed
+        // major version, from which minor branches are made
         return version;
     }
 
@@ -442,10 +442,13 @@ std::optional<NKikimrConfig::TYdbVersion> ParseVersionFromTag(TString tag, TStri
     parts.pop_front();
     version.SetMinor(minor);
 
+    if (parts.empty()) {
+        // example: stable-25-1-14 == 25.1.14
+        // minor version, from which release tags are made
+        return version;
+    }
+
     // parse Patch number
-    // We don't need to parse versions without Patch component, since this
-    // code only present in newer trunks and stables >=25.1, where Patch is
-    // already introduced, and only used to parse local 
     ui32 patch;
     if (!TryIntFromString<10, ui32>(parts.front(), patch)) {
         // example: stable-25-1-1-prestablle == 25.1.1