SaraFem's file picker without a password where possible; clearer pkexec errors; portals.conf without a desktop name

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Core.py

@@ -13,6 +13,7 @@ picked for one Sara program looks the same in all of them.
 """
 
 import os
+import re
 import shutil
 import sys
 from dataclasses import asdict, dataclass, field
@@ -268,6 +269,26 @@ def ChildEnvironment() -> dict[str, str]:
     return Environment
 
 
+def UserPortalsSupported() -> bool:
+    """Whether xdg-desktop-portal reads portal files from
+    ~/.local/share/xdg-desktop-portal/portals (1.17 and newer), so installing
+    one needs no password. True when it isn't installed either: then a
+    portal file can't be used anywhere, so it might as well not need root."""
+    import subprocess
+
+    for Candidate in ("/usr/libexec/xdg-desktop-portal", "/usr/lib/xdg-desktop-portal",
+                      "/usr/lib/x86_64-linux-gnu/xdg-desktop-portal", "/usr/local/libexec/xdg-desktop-portal"):
+        if not Path(Candidate).is_file():
+            continue
+        try:
+            Output = subprocess.run([Candidate, "--version"], capture_output=True, text=True, timeout=10).stdout
+        except (OSError, subprocess.SubprocessError):
+            return False
+        Found = re.search(r"(\d+)\.(\d+)", Output)
+        return bool(Found) and (int(Found[1]), int(Found[2])) >= (1, 17)
+    return True
+
+
 def CurrentDesktop() -> str:
     """First entry of $XDG_CURRENT_DESKTOP as-is (e.g. "COSMIC"), used for
     portal descriptors' UseIn= and the <desktop>-portals.conf file name.

Installer.py

@@ -21,8 +21,8 @@ from typing import Callable, Optional
 from ConfigMerge import ApplySet, MergeConfig, MergeResult
 import Services
 from Core import (
-    AutostartDir, BackupsDir, ChildEnvironment, DownloadsDir, HasSystemd, IsWindows, LoadConfig, PristineDir,
-    StartMenuDir, StartupDir,
+    AutostartDir, BackupsDir, ChildEnvironment, DownloadsDir, HasSystemd, Home, IsWindows, LoadConfig,
+    PristineDir, StartMenuDir, StartupDir,
 )
 from Manifests import Leftover, Program, Render
 from Receipts import IniRecord, LoadReceipt, PlacedFile, Receipt
@@ -81,18 +81,47 @@ def _BackupName(Target: str) -> str:
     return Target.strip("/").replace("/", "__")
 
 
+def _Pkexec(Command: list[str], Log: LogFn, Check: bool = True) -> int:
+    """Run Command as root through pkexec, saying what went wrong in words."""
+    if shutil.which("pkexec") is None:
+        Code = 127
+    else:
+        Code = _Run(["pkexec", *Command], Log, Check=False)
+    if Code == 0:
+        return 0
+    if Code == 126:
+        Problem = "the password prompt was cancelled"
+    elif shutil.which("pkexec") is None:
+        Problem = "pkexec (polkit) isn't installed"
+    else:
+        Problem = ("no password prompt could be shown: polkit needs an authentication agent running "
+                   "in your session (e.g. polkit-gnome or lxqt-policykit), which window managers don't start themselves")
+    Message = f"Couldn't do this as root ({Problem}). The command was: sudo {' '.join(Command)}"
+    if Check:
+        raise InstallError(Message)
+    Log(f"Warning: {Message}")
+    return Code
+
+
+def _NeedsRoot(Template, Target: str) -> bool:
+    if Template.Root == "Auto":
+        return not (Target == str(Home) or Target.startswith(f"{Home}{os.sep}"))
+    return bool(Template.Root)
+
+
 def _WriteRoot(Target: str, Text: str, Log: LogFn) -> None:
     with tempfile.NamedTemporaryFile("w", delete=False, suffix=".sarasuite") as Temporary:
         Temporary.write(Text)
     os.chmod(Temporary.name, 0o644)
     try:
-        _Run(["pkexec", "install", "-D", "-m", "644", Temporary.name, Target], Log)
+        _Pkexec(["install", "-D", "-m", "644", Temporary.name, Target], Log)
     finally:
         os.unlink(Temporary.name)
 
 
 def _RemoveRoot(Target: str, Log: LogFn) -> None:
-    _Run(["pkexec", "rm", "-f", Target], Log)
+    # A leftover outside $HOME isn't worth failing an install or removal over.
+    _Pkexec(["rm", "-f", Target], Log, Check=False)
 
 
 def _ReadIni(FilePath: Path) -> configparser.ConfigParser:
@@ -381,7 +410,8 @@ def _ApplyTemplates(Program: Program, Context: dict, OldReceipt: Optional[Receip
         Target = Render(Template.Target, Context)
         Text = Render((Program.Folder / "Templates" / Template.Source).read_text(), Context)
         Previous = OldReceipt.FindFile(Target) if OldReceipt is not None else None
-        Placed = PlacedFile(Target, "Template", Root=Template.Root, Displaced=Previous.Displaced if Previous else "")
+        Root = _NeedsRoot(Template, Target)
+        Placed = PlacedFile(Target, "Template", Root=Root, Displaced=Previous.Displaced if Previous else "")
 
         # A file that's already there but wasn't placed by SaraSuite (e.g. a
         # hand-made desktop entry from development) is moved aside, not lost.
@@ -393,7 +423,7 @@ def _ApplyTemplates(Program: Program, Context: dict, OldReceipt: Optional[Receip
             Log(f"Moved your existing {Target} aside (it comes back if {Program.Name} is removed)")
 
         NewReceipt.Files.append(Placed)
-        if Template.Root:
+        if Root:
             if Path(Target).exists() and Path(Target).read_text() == Text:
                 continue
             _WriteRoot(Target, Text, Log)

Manifests.py

@@ -17,7 +17,7 @@ import tomlkit
 
 from Core import (
     AutostartDir, CacheHome, ConfigHome, CurrentDesktop, DataHome, HasSystemd, Home, IsWindows, LoadConfig,
-    Platform, ProgramsDir, SharedConfigDir, StartMenuDir, StartupDir,
+    Platform, ProgramsDir, SharedConfigDir, StartMenuDir, StartupDir, UserPortalsSupported,
 )
 
 # Never worth copying out of a source checkout, whatever Include says.
@@ -55,7 +55,9 @@ class TemplateFile:
     Source: str  # relative to the program's Templates/ folder
     Target: str
     Option: str = ""
-    Root: bool = False  # lives outside $HOME, written through pkexec
+    # True: lives outside $HOME, written through pkexec. "Auto": only when its
+    # Target turns out to be outside $HOME (e.g. {PortalsDir} on an old system).
+    Root: bool | str = False
     Executable: bool = False
 
 
@@ -239,6 +241,14 @@ class Program:
                 AutostartDir=str(AutostartDir),
                 ApplicationsDir=str(DataHome / "applications"),
                 DBusServicesDir=str(DataHome / "dbus-1" / "services"),
+                # xdg-desktop-portal: where a portal file goes (your own folder
+                # where it's new enough, no password), the preferences file
+                # (portals.conf without a desktop name, e.g. a window manager),
+                # and the desktop's own entry in its list ("cosmic;" or "").
+                PortalsDir=str(DataHome / "xdg-desktop-portal" / "portals") if UserPortalsSupported()
+                else "/usr/share/xdg-desktop-portal/portals",
+                PortalsConf=f"{Desktop.lower()}-portals.conf" if Desktop else "portals.conf",
+                DesktopPortal=f"{Desktop.lower()};" if Desktop else "",
             )
         Context.update(Answers or {})
         return Context

Programs/SaraFem/Manifest.toml

@@ -18,7 +18,7 @@ RequirementsFile = "requirements.txt"
 [[Options]]
 Platform = "Linux"
 Id = "FilePicker"
-Label = "Use SaraFem as the system file picker (asks for your password: the portal file lives in /usr/share)"
+Label = "Use SaraFem as the system file picker"
 Default = true
 
 [[Options]]
@@ -48,16 +48,18 @@ Option = "FilePicker"
 [[Templates]]
 Platform = "Linux"
 Source = "SaraFem.portal"
-Target = "/usr/share/xdg-desktop-portal/portals/SaraFem.portal"
+# In your own folder where xdg-desktop-portal is new enough (1.17+); in
+# /usr/share, through pkexec, on older systems.
+Target = "{PortalsDir}/SaraFem.portal"
 Option = "FilePicker"
-Root = true
+Root = "Auto"
 
 [[IniEdits]]
 Platform = "Linux"
-File = "{ConfigHome}/xdg-desktop-portal/{Desktop}-portals.conf"
+File = "{ConfigHome}/xdg-desktop-portal/{PortalsConf}"
 Section = "preferred"
 Key = "org.freedesktop.impl.portal.FileChooser"
-Value = "SaraFem;{Desktop};gtk;"
+Value = "SaraFem;{DesktopPortal}gtk;"
 Option = "FilePicker"
 
 [[IniEdits]]