Refuse a game folder whose path leaves no room for the game's files.

Windows and the build tools stop at 260 characters for a file's whole path, and a built game needs up to 128 below
its folder. A deeper folder made the build stop in the middle with a file "not found"; Begin Installation and the
install job now refuse it first and name both lengths.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

launcher/jobs.py

@@ -9,7 +9,7 @@ import threading
 import time
 import traceback
 
-from . import build, feed, gamefiles, locks, net, toolchain, updater, versions, winsys
+from . import build, feed, gamefiles, locks, net, paths, toolchain, updater, versions, winsys
 
 RECHECK = 3600   # seconds between update checks while the launcher stays open, hidden during play included
 
@@ -456,6 +456,9 @@ class InstallJob(Job):
         return build.install_args(self.ctx.layout, self.dump, self.game_dir)
 
     def run(self):
+        too_long = paths.long_path_problem(self.game_dir)   # the window asks first (begin_install); the command line here
+        if too_long:
+            raise build.BuildError(too_long)
         self.ensure_tools('tools')
         self.make_game(self.args(),
                        {s: s for s in ('check', 'exefs', 'romfs', 'lift', 'compile', 'shaders', 'prompts', 'scan')})

launcher/paths.py

@@ -38,6 +38,29 @@ def ansi_safe(path):
         return False
 
 
+# Windows: a file's whole path may be 259 characters for the programs that do not ask for more, and the build's tools
+# (the MSYS2 compiler, linker and resource compiler, tar) are among them whatever the system's long path setting.
+# LONGEST_IN_GAME is the room the game folder's own files need below it: the longest path a built game folder held
+# was 106 characters (romfs-patches-playstation-label\System\Resource\ResourceSizeTable...rsizetable.zs), and a file
+# is written under a temporary name up to 22 characters longer before it gets its own.
+WINDOWS_PATH_MAX = 259
+LONGEST_IN_GAME = 128
+
+
+def long_path_problem(game_dir):
+    """'' when the files of a game built into game_dir fit Windows' path length, else the sentence that says how long
+    the folder's path is and how long it may be. Always '' elsewhere. Without it a build into a deep folder stops
+    somewhere in the middle with "file not found" for a file that is there."""
+    if os.name != 'nt' or not game_dir:
+        return ''
+    n, most = len(os.path.abspath(str(game_dir))), WINDOWS_PATH_MAX - 1 - LONGEST_IN_GAME
+    if n <= most:
+        return ''
+    return (f'the path of the game folder is {n} characters long, and the game\'s files need {LONGEST_IN_GAME} more: '
+            f'Windows and the build tools stop at {WINDOWS_PATH_MAX + 1} for a file\'s whole path. Choose a folder '
+            f'whose path has at most {most} characters, such as D:\\Games\\NX2navi')
+
+
 def fixed_drive(drive):
     """True when drive (X:\\) is a fixed disk (GetDriveTypeW DRIVE_FIXED), not a network, removable or optical drive.
     True where that cannot be asked."""

launcher/ui/app.py

@@ -39,6 +39,7 @@ from tkinter import filedialog
 
 from .. import NAME, build, feed, gameini, gamefiles, jobs, locks, mods, saves, steam, versions, winsys
 from ..context import Context
+from ..paths import long_path_problem
 from . import art, picture, sound
 
 W, H = 1000, 640
@@ -966,6 +967,11 @@ class App:
             self.choose_dump()
             return
         gd = self.game_dir()
+        too_long = long_path_problem(gd)   # told here, not as a missing file halfway through the build
+        if too_long:
+            self.message = App.friendly(too_long)
+            self.render()
+            return
         drop_partial_image(gd)   # before the free space is measured
         if free_gb(gd) < 34 and not (Path(gd) / 'romfs' / 'romfs.bin').is_file():
             self.message = f'{drive_of(gd)} has {free_gb(gd):.0f} GB free; the game needs about 34 GB.'