"Pad" shorter versions with empty parts when comparing (#5009)

Cherry Pick #5001 into `release-v1.9`
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Author: Trenly

src/AppInstallerCLITests/SQLiteIndex.cpp

@@ -1911,8 +1911,8 @@ TEST_CASE("SQLiteIndex_Search_VersionSorting", "[sqliteindex]")
     {
         { UtilityVersion("15.0.0"), Channel("") },
         { UtilityVersion("14.0.0"), Channel("") },
-        { UtilityVersion("13.2.0-bugfix"), Channel("") },
         { UtilityVersion("13.2.0"), Channel("") },
+        { UtilityVersion("13.2.0-bugfix"), Channel("") },
         { UtilityVersion("13.0.0"), Channel("") },
         { UtilityVersion("16.0.0"), Channel("alpha") },
         { UtilityVersion("15.8.0"), Channel("alpha") },
@@ -1966,8 +1966,8 @@ TEST_CASE("SQLiteIndex_PathString_VersionSorting", "[sqliteindex]")
     {
         { UtilityVersion("15.0.0"), Channel("") },
         { UtilityVersion("14.0.0"), Channel("") },
-        { UtilityVersion("13.2.0-bugfix"), Channel("") },
         { UtilityVersion("13.2.0"), Channel("") },
+        { UtilityVersion("13.2.0-bugfix"), Channel("") },
         { UtilityVersion("13.0.0"), Channel("") },
         { UtilityVersion("16.0.0"), Channel("alpha") },
         { UtilityVersion("15.8.0"), Channel("alpha") },

src/AppInstallerCLITests/Versions.cpp

@@ -154,6 +154,20 @@ TEST_CASE("VersionCompare", "[versions]")
     RequireLessThan("0.0.1-beta", "0.0.2-alpha");
     RequireLessThan("13.9.8", "14.1");
 
+    // Ensure that versions with non-digit characters in their parts are sorted correctly
+    RequireLessThan("1-rc", "1");
+    RequireLessThan("1.2-rc", "1.2");
+    RequireLessThan("1.0-rc", "1.0");
+    RequireLessThan("1.0.0-rc", "1");
+    RequireLessThan("22.0.0-rc.1", "22.0.0");
+    RequireLessThan("22.0.0-rc.1", "22.0.0.1");
+    RequireLessThan("22.0.0-rc.1", "22.0.0.1-rc");
+
+    // Ensure that Sub-RC versions are sorted correctly
+    RequireLessThan("22.0.0-rc.1", "22.0.0-rc.1.1");
+    RequireLessThan("22.0.0-rc.1.1", "22.0.0-rc.1.2");
+    RequireLessThan("22.0.0-rc.1.2", "22.0.0-rc.2");
+
     RequireEqual("1.0", "1.0.0");
 
     // Ensure whitespace doesn't affect equality
@@ -175,15 +189,16 @@ TEST_CASE("VersionAndChannelSort", "[versions]")
     {
         { Version("15.0.0"), Channel("") },
         { Version("14.0.0"), Channel("") },
-        { Version("13.2.0-bugfix"), Channel("") },
+        { Version("13.2.1-bugfix"), Channel("") },
         { Version("13.2.0"), Channel("") },
+        { Version("13.2.0-rc"), Channel("") },
         { Version("13.0.0"), Channel("") },
         { Version("16.0.0"), Channel("alpha") },
         { Version("15.8.0"), Channel("alpha") },
         { Version("15.1.0"), Channel("beta") },
     };
 
-    std::vector<size_t> reorderList = { 4, 2, 1, 7, 6, 3, 5, 0 };
+    std::vector<size_t> reorderList = { 4, 2, 1, 7, 6, 3, 8, 5, 0 };
     REQUIRE(sortedList.size() == reorderList.size());
 
     std::vector<VersionAndChannel> jumbledList;

src/AppInstallerSharedLib/Public/AppInstallerVersions.h

@@ -18,12 +18,11 @@ namespace AppInstaller::Utility
     //
     // Versions are compared by:
     //  for each part in each version
-    //      if both sides have no more parts, return equal
-    //      else if one side has no more parts, it is less
-    //      else if integers not equal, return comparison of integers
+    //      if one side has no more parts, perform the remaining comparisons against an empty part
+    //      if integers not equal, return comparison of integers
     //      else if only one side has a non-empty string part, it is less
     //      else if string parts not equal, return comparison of strings
-    //  if all parts are same, use approximate comparator if applicable
+    //  if each part has been compared, use approximate comparator if applicable
     //
     //  Note: approximate to another approximate version is invalid.
     //        approximate to Unknown is invalid.

src/AppInstallerSharedLib/Versions.cpp

@@ -137,16 +137,12 @@ namespace AppInstaller::Utility
             return (thisIsUnknown && !otherIsUnknown);
         }
 
-        for (size_t i = 0; i < m_parts.size(); ++i)
+        const Part emptyPart{};
+        for (size_t i = 0; i < std::max(m_parts.size(), other.m_parts.size()); ++i)
         {
-            if (i >= other.m_parts.size())
-            {
-                // All parts equal to this point
-                break;
-            }
-
-            const Part& partA = m_parts[i];
-            const Part& partB = other.m_parts[i];
+            // Whichever version is shorter, we need to pad it with empty parts
+            const Part& partA = (i >= m_parts.size()) ? emptyPart : m_parts[i];
+            const Part& partB = (i >= other.m_parts.size()) ? emptyPart : other.m_parts[i];
 
             if (partA < partB)
             {
@@ -159,17 +155,8 @@ namespace AppInstaller::Utility
             // else parts are equal, so continue to next part
         }
 
-        // All parts tested were equal
-        if (m_parts.size() == other.m_parts.size())
-        {
-            return ApproximateCompareLessThan(other);
-        }
-        else
-        {
-            // Else this is only less if there are more parts in other.
-            return m_parts.size() < other.m_parts.size();
-        }
-        
+        // All parts were compared and found to be equal
+        return ApproximateCompareLessThan(other);
     }
 
     bool Version::operator>(const Version& other) const