[instancer/CFF2] Micro-optimize commands

Lib/fontTools/varLib/instancer/__init__.py

@@ -751,7 +751,10 @@ def instantiateCFF2(
 
     # Empty out the VarStore
     for i, varData in enumerate(varStore.VarData):
-        assert varDataCursor[i] == varData.ItemCount, (varDataCursor[i], varData.ItemCount)
+        assert varDataCursor[i] == varData.ItemCount, (
+            varDataCursor[i],
+            varData.ItemCount,
+        )
         varData.Item = []
         varData.ItemCount = 0
 
@@ -779,6 +782,11 @@ def instantiateCFF2(
             if command[0] == "vsindex":
                 command[1][0] = vsindexMapping[command[1][0]]
 
+    # Remove initial vsindex commands that are implied
+    for commands in allCommands:
+        if commands and commands[0] == ("vsindex", [0]):
+            commands.pop(0)
+
     # Ship the charstrings!
     for cs, commands in zip(charStrings, allCommands):
         cs.program = commandsToProgram(commands)

Tests/varLib/instancer/data/test_results/CFF2Instancer-VF-2-instance-400.ttx

@@ -183,7 +183,6 @@
         <CharString name=".notdef">
         </CharString>
         <CharString name="A">
-          0 vsindex
           9 30 1 blend
           hmoveto
           122 31 1 blend