migrate: Fix --remove-size to work when a file is not present

5f74a45861 added this bug

CHANGELOG

@@ -9,6 +9,8 @@ git-annex (10.20250321) UNRELEASED; urgency=medium
   * httpalso: Windows url fix.
   * Added remote.name.annex-web-options config, which is a per-remote
     version of the annex.web-options config.
+  * migrate: Fix --remove-size to work when a file is not present.
+    Fixes reversion introduced in version 10.20231129.
 
  -- Joey Hess <id@joeyh.name>  Fri, 21 Mar 2025 12:27:11 -0400
 

Command/Migrate.hs

@@ -90,7 +90,7 @@ start o ksha si file key = do
 			newbackend <- chooseBackend file
 			if (newbackend /= oldbackend || upgradableKey oldbackend || forced) && exists
 				then go False oldbackend newbackend
-				else if cantweaksize newbackend oldbackend && exists
+				else if cantweaksize newbackend oldbackend exists
 					then go True oldbackend newbackend
 					else stop
   where
@@ -101,10 +101,10 @@ start o ksha si file key = do
 		starting "migrate" (mkActionItem (key, file)) si $
 			perform onlytweaksize o file key keyrec oldbackend newbackend
 
-	cantweaksize newbackend oldbackend
+	cantweaksize newbackend oldbackend exists
 		| removeSize o = isJust (fromKey keySize key)
 		| newbackend /= oldbackend = False
-		| isNothing (fromKey keySize key) = True
+		| isNothing (fromKey keySize key) && exists = True
 		| otherwise = False
 
 	upgradableKey oldbackend = maybe False (\a -> a key) (canUpgradeKey oldbackend)

doc/bugs/migrate_--remove-size_does_nothing.mdwn

@@ -92,4 +92,4 @@ git-annex version: 10.20250115
 
 
 
-
+> [[fixed|done]] --[[Joey]]

doc/bugs/migrate_--remove-size_does_nothing/comment_1_57e0c4a6b4183a9e08894a7c25b2efda._comment

@@ -0,0 +1,10 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 1"""
+ date="2025-04-01T14:39:24Z"
+ content="""
+I diagnose a bug introduced in 
+[[!commit 86dbe9a825b9c615c63e0cfc5e4a737a249f8989]]
+that makes it only be able to remove the size if the object file is locally
+present. Fixed.
+"""]]