fix(desktop-file): verify theme icons before rewriting icon

[soumyaDghosh]

Theme-resolved icon path was written to the desktop file without checking the file exists, and the subsequent existence check ran against the bare icon name stored in icon variable, emitting a spurious "not found" warning. Assign the resolved path to the local var first so the same check covers theme icons.

Fixes #6364

IMO, this complete function should be refactored, including early return when icon is None, converting these 2 lines into a single one liner and remove any prefixed $SNAP as well

@@ -89,11 +89,8 @@ class DesktopFile:
             if icon_path is not None:
                 icon = icon_path
 
-            # Strip any leading slash.
-            icon = icon[1:] if icon.startswith("/") else icon
-
-            # Strip any leading ${SNAP}.
-            icon = icon[8:] if icon.startswith("${SNAP}") else icon
+            # Strip any leading slash, ${SNAP} and $SNAP variable
+            icon.removeprefix("/").removeprefix("${SNAP}").removeprefix("$SNAP")
 
             # If icon is just a name (no path separator), try to resolve it from the hicolor icon theme.
             if "/" not in icon:

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[Copilot]

Pull request overview

Fixes incorrect “Icon not found” warnings when a desktop file’s Icon= value is a theme icon name that gets resolved from the hicolor theme during desktop file rewriting (Fixes #6364).

Changes:

• Update theme icon resolution logic to assign the resolved theme path to the local icon variable (so the subsequent existence check validates the resolved path).
• Avoid writing the theme-resolved ${SNAP}/… icon path into the desktop file before the file existence check has passed.