Project Manager: Fix hacky code for project rename

[akien-mga]

Instantiating a new ProjectSettings is not the way to go. ConfigFile works just fine to read/change a single value.

Fixes memory leaks as the instantiated ProjectSettings was never freed.

• Fixes A lot of warnings "Property not found:" when trying to rename project #25661.
• Supersedes Retain configuration meta data on ProjectSettings #67579.

[mhilbrunner]

PR council approves

[akien-mga]

So I checked after someone mentioned it in the PR meeting, and indeed there's a potential risk of losing information by going through the ConfigFile API. Here's the diff after rename for a test project with a few global script classes:

--- project.godot.bkp   2022-11-29 15:43:40.739102066 +0100
+++ project.godot       2022-11-29 15:43:47.488103630 +0100
@@ -1,13 +1,4 @@
-; Engine configuration file.
-; It's best edited using the editor UI and not directly,
-; since the parameters that go here are not all obvious.
-;
-; Format:
-;   [section] ; section goes between []
-;   param=value ; assign values to parameters
-
 config_version=5
-
 _global_script_classes=[{
 "base": "Node",
 "class": &"MyClass",
@@ -26,7 +17,7 @@
 
 [application]
 
-config/name="New Game Project test"
+config/name="New Game Project"
 run/main_scene="res://node_2d.tscn"
 config/features=PackedStringArray("4.0")
 config/icon="res://icon.svg"

So it removes comments, and the separation line between config_version and _global_script_classes.
Those are possibly the only elements in project.godot which differ from a proper ConfigFile. Might be worth changing that...

Edit: But then when editing the project, Godot restores the comment and separation line so the diff becomes:

--- project.godot.bkp   2022-11-29 15:43:40.739102066 +0100
+++ project.godot       2022-11-29 15:46:43.913144506 +0100
@@ -26,7 +26,7 @@
 
 [application]
 
-config/name="New Game Project test"
+config/name="New Game Project"
 run/main_scene="res://node_2d.tscn"
 config/features=PackedStringArray("4.0")
 config/icon="res://icon.svg"

So it's pretty good? I don't know if there are more complex project.godot files where there's actual risk of data loss though.

[YuriSizov]

Might be worth changing that...

I'd go with "Allow ConfigFile to preserve formatting (spacing, comments)", but that'd take some effort. I guess if someone complains, asking them to open the project once is okay.

[YuriSizov]

Tested it with a realistic project and it didn't break anything else. I think it's okay as an immediate solution, though it'd be nice to preserve formatting with ConfigFile. Task for another day.

[YuriSizov]

Let's see if this causes problems with the next beta. Thanks for the quick turnaround!

[akien-mga]

Cherry-picked for 3.6.

[timothyqiu]

Cherry-picked for 3.5.2