Test: never enter the real WSL cleanup from the webview-data test

Stubbing uname alone is not enough on a WSL host: the script's
'grep -qi microsoft /proc/version' probe still fires and the Linux test
cases would run the real WSL cleanup against the host's /mnt/* shortcuts
and /etc profile. Add a PATH-stubbed grep that fails only the
/proc/version probe (delegating everything else to the real grep via an
absolute path so the stub can never self-exec), plus no-op
powershell.exe and sudo stubs as defense in depth.

scripts/uninstall.ps1

@@ -3,8 +3,10 @@
 #
 # Unsloth Studio uninstaller for Windows PowerShell.
 # Stops running servers and removes install dir, launcher data, CLI shim,
-# desktop and Start Menu shortcuts, the user PATH entry, and the PathBackup
-# registry key. Honors custom roots set via UNSLOTH_STUDIO_HOME / STUDIO_HOME
+# desktop and Start Menu shortcuts, the user PATH entry, the PathBackup
+# registry key, and WebView2 runtime data keyed by the app bundle id
+# (EBWebView caches created at first desktop-app launch, not by install.ps1).
+# Honors custom roots set via UNSLOTH_STUDIO_HOME / STUDIO_HOME
 # at install time (read back from share\studio.conf).
 #
 # Usage:  irm https://raw.githubusercontent.com/unslothai/unsloth/main/scripts/uninstall.ps1 | iex
@@ -398,6 +400,32 @@ function Uninstall-UnslothStudio {
         _RemovePath $defaultUnslothHome
     }
 
+    # WebView2/app runtime data keyed by the Tauri bundle id. Created at first
+    # desktop-app launch, not by install.ps1. LOCALAPPDATA holds the EBWebView
+    # profile (a leftover copy serves a stale frontend to the next install);
+    # APPDATA holds the app config dir.
+    _Step "Removing WebView caches and app data (ai.unsloth.studio)..."
+    $bundleId = "ai.unsloth.studio"
+    $webviewDataDirs = @()
+    if ($env:LOCALAPPDATA) { $webviewDataDirs += Join-Path $env:LOCALAPPDATA $bundleId }
+    if ($env:APPDATA) { $webviewDataDirs += Join-Path $env:APPDATA $bundleId }
+    # Stop the desktop app and any msedgewebview2.exe helper using these dirs
+    # first; WebView2 keeps open handles that make the delete fail.
+    try { Stop-Process -Name "unsloth-studio" -Force -ErrorAction SilentlyContinue } catch { }
+    try {
+        foreach ($proc in (Get-CimInstance Win32_Process -Filter "Name = 'msedgewebview2.exe'" -ErrorAction SilentlyContinue)) {
+            $cl = $proc.CommandLine
+            if (-not $cl) { continue }
+            foreach ($d in $webviewDataDirs) {
+                if ($cl -ilike "*$d*") {
+                    try { Stop-Process -Id $proc.ProcessId -Force -ErrorAction SilentlyContinue } catch { }
+                    break
+                }
+            }
+        }
+    } catch { }
+    foreach ($d in $webviewDataDirs) { _RemovePath $d }
+
     # ── Remove desktop and Start Menu shortcuts ──
     _Step "Removing desktop and Start Menu shortcuts..."
     try {

scripts/uninstall.sh

@@ -4,7 +4,9 @@
 #
 # Unsloth Studio uninstaller (macOS / Linux / WSL).
 # Stops running servers and removes install dir, launcher data,
-# CLI shim, desktop shortcut, .app bundle, and Launch Services entry.
+# CLI shim, desktop shortcut, .app bundle, Launch Services entry, and
+# WebView runtime data keyed by the app bundle id (WebKit/webkit2gtk
+# caches created at first app launch, not by install.sh).
 # Honors custom roots set via UNSLOTH_STUDIO_HOME / STUDIO_HOME at
 # install time (read back from studio.conf).
 #
@@ -80,6 +82,13 @@ $_roots_from_conf"
             pkill -KILL -f "$_pat" 2>/dev/null || true
         done
     done
+
+    # Tauri desktop app (binary "unsloth-studio"): stop it so its WebView
+    # helpers can't hold or re-create the runtime caches removed below.
+    # -x is an exact name match, so the "unsloth" CLI shim is never touched.
+    pkill -TERM -x unsloth-studio 2>/dev/null || true
+    sleep 0.5
+    pkill -KILL -x unsloth-studio 2>/dev/null || true
 }
 
 _remove_path() {
@@ -261,6 +270,25 @@ case "$_os" in
         if [ -x "$_lsr" ]; then
             "$_lsr" -u "$HOME/Applications/Unsloth Studio.app" 2>/dev/null || true
         fi
+        # WebView/app runtime data keyed by the bundle id. Created by macOS +
+        # WKWebView at first app launch, not by install.sh, so it survives an
+        # uninstall and a leftover WebKit cache then serves a stale frontend
+        # to the next install.
+        _bid="ai.unsloth.studio"
+        echo "Removing WebView caches and app data ($_bid)..."
+        _remove_path "$HOME/Library/Caches/$_bid"
+        _remove_path "$HOME/Library/WebKit/$_bid"
+        _remove_path "$HOME/Library/Application Support/$_bid"
+        _remove_path "$HOME/Library/HTTPStorages/$_bid"
+        _remove_path "$HOME/Library/HTTPStorages/$_bid.binarycookies"
+        _remove_path "$HOME/Library/Cookies/$_bid.binarycookies"
+        _remove_path "$HOME/Library/Saved Application State/$_bid.savedState"
+        # Delete via defaults first: cfprefsd caches plists in memory and can
+        # re-write the file after a bare rm.
+        if command -v defaults >/dev/null 2>&1; then
+            defaults delete "$_bid" >/dev/null 2>&1 || true
+        fi
+        _remove_path "$HOME/Library/Preferences/$_bid.plist"
         ;;
     Linux)
         if [ "$_is_wsl" = "1" ]; then
@@ -403,6 +431,15 @@ case "$_os" in
                 echo "          sudo rm -rf /opt/rocm /opt/rocm-* && sudo ldconfig"
             fi
         fi
+        # WebView/app runtime data keyed by the Tauri bundle id. Created by
+        # webkit2gtk at first desktop-app launch, not by install.sh; a
+        # leftover cache serves a stale frontend to the next install.
+        _bid="ai.unsloth.studio"
+        echo "Removing WebView caches and app data ($_bid)..."
+        _remove_path "${XDG_CACHE_HOME:-$HOME/.cache}/$_bid"
+        _remove_path "${XDG_DATA_HOME:-$HOME/.local/share}/$_bid"
+        _remove_path "${XDG_CONFIG_HOME:-$HOME/.config}/$_bid"
+        _remove_path "${XDG_STATE_HOME:-$HOME/.local/state}/$_bid"
         echo "Removing Linux .desktop entry..."
         _remove_path "$HOME/.local/share/applications/unsloth-studio.desktop"
         if command -v update-desktop-database >/dev/null 2>&1; then

tests/run_all.sh

@@ -14,6 +14,7 @@ sh "$TESTS_DIR/sh/test_nvcc_meets_llama_minimum.sh"
 sh "$TESTS_DIR/sh/test_resolve_cuda_archs.sh"
 sh "$TESTS_DIR/sh/test_strixhalo_wsl_reroute.sh"
 sh "$TESTS_DIR/sh/test_uninstall_shared_icon.sh"
+sh "$TESTS_DIR/sh/test_uninstall_webview_data.sh"
 sh "$TESTS_DIR/sh/test_torch_flavor.sh"
 sh "$TESTS_DIR/sh/test_redact_install_output.sh"
 sh "$TESTS_DIR/sh/test_install_uv_override_space.sh"

tests/sh/test_uninstall_webview_data.sh

@@ -0,0 +1,129 @@
+#!/bin/bash
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
+# Regression tests for WebView runtime-data cleanup in scripts/uninstall.sh.
+#
+# WKWebView (macOS) and webkit2gtk (Linux) create data keyed by the bundle id
+# at first app launch, not at install time, so the uninstaller used to miss it
+# and a leftover cache served a stale frontend to the next install. Runs the
+# full script against a fixture HOME (pkill/defaults stubbed via PATH, OS
+# branch picked by a stubbed uname, /proc/version WSL probe force-failed) and
+# asserts bundle-id paths are removed while unrelated app data survives.
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+UNINSTALL_SH="$SCRIPT_DIR/../../scripts/uninstall.sh"
+BID="ai.unsloth.studio"
+PASS=0
+FAIL=0
+
+_TMP_ROOT=$(mktemp -d)
+trap 'rm -rf "$_TMP_ROOT"' EXIT
+
+assert_gone()    { _l="$1"; if [ -e "$2" ]; then echo "  FAIL: $_l (still present: $2)"; FAIL=$((FAIL+1)); else echo "  PASS: $_l"; PASS=$((PASS+1)); fi; }
+assert_present() { _l="$1"; if [ -e "$2" ]; then echo "  PASS: $_l"; PASS=$((PASS+1)); else echo "  FAIL: $_l (missing: $2)"; FAIL=$((FAIL+1)); fi; }
+
+# Stub out process kills and macOS pref/LaunchServices tools so the script can
+# run against a fixture HOME without touching the real system.
+STUB_BIN="$_TMP_ROOT/stubbin"
+mkdir -p "$STUB_BIN"
+for _tool in pkill defaults; do
+    printf '#!/bin/sh\nexit 0\n' > "$STUB_BIN/$_tool"
+    chmod +x "$STUB_BIN/$_tool"
+done
+# Force the non-WSL path: with uname stubbed to Linux on a WSL host, the
+# script's `grep -qi microsoft /proc/version` probe would still fire and the
+# real WSL cleanup would touch the host's /mnt/* shortcuts and /etc profile.
+# Fail that one probe; delegate every other grep call to the real grep.
+# REAL_GREP must be an absolute path: a bare "grep" (e.g. from an alias-shaped
+# `command -v` result) would resolve back to this stub and self-exec forever.
+REAL_GREP=$(command -v grep)
+case "$REAL_GREP" in /*) ;; *) REAL_GREP=/usr/bin/grep ;; esac
+cat > "$STUB_BIN/grep" <<EOF
+#!/bin/sh
+for _a in "\$@"; do
+    [ "\$_a" = "/proc/version" ] && exit 1
+done
+exec "$REAL_GREP" "\$@"
+EOF
+chmod +x "$STUB_BIN/grep"
+# Belt and braces should the WSL branch ever be entered anyway: powershell.exe
+# exiting 0 makes its no-op path taken (and skips the /mnt/* drvfs fallback);
+# sudo exiting 0 without running its argv keeps /etc untouched.
+for _tool in powershell.exe sudo; do
+    printf '#!/bin/sh\nexit 0\n' > "$STUB_BIN/$_tool"
+    chmod +x "$STUB_BIN/$_tool"
+done
+
+# run_uninstall <home> <uname_output> : run the full script with a stubbed OS.
+run_uninstall() {
+    printf '#!/bin/sh\necho %s\n' "$2" > "$STUB_BIN/uname"
+    chmod +x "$STUB_BIN/uname"
+    env -u UNSLOTH_STUDIO_HOME -u STUDIO_HOME \
+        -u XDG_CACHE_HOME -u XDG_DATA_HOME -u XDG_CONFIG_HOME -u XDG_STATE_HOME \
+        HOME="$1" PATH="$STUB_BIN:$PATH" sh "$UNINSTALL_SH" >/dev/null 2>&1
+}
+
+# ── 1. macOS: every bundle-id-keyed ~/Library path is removed ──
+H=$(mktemp -d -p "$_TMP_ROOT")
+mkdir -p "$H/Library/Caches/$BID/WebKit/NetworkCache" \
+         "$H/Library/WebKit/$BID/WebsiteData/CacheStorage" \
+         "$H/Library/Application Support/$BID" \
+         "$H/Library/HTTPStorages/$BID" \
+         "$H/Library/Saved Application State/$BID.savedState" \
+         "$H/Library/Preferences" \
+         "$H/Library/Cookies" \
+         "$H/Library/Caches/com.other.app"
+: > "$H/Library/HTTPStorages/$BID.binarycookies"
+: > "$H/Library/Cookies/$BID.binarycookies"
+: > "$H/Library/Preferences/$BID.plist"
+: > "$H/Library/Caches/$BID/stale-frontend.js"
+: > "$H/Library/Caches/com.other.app/keepme"
+run_uninstall "$H" Darwin
+assert_gone "macOS: Caches/$BID removed"                     "$H/Library/Caches/$BID"
+assert_gone "macOS: WebKit/$BID removed"                     "$H/Library/WebKit/$BID"
+assert_gone "macOS: Application Support/$BID removed"        "$H/Library/Application Support/$BID"
+assert_gone "macOS: HTTPStorages/$BID removed"               "$H/Library/HTTPStorages/$BID"
+assert_gone "macOS: HTTPStorages/$BID.binarycookies removed" "$H/Library/HTTPStorages/$BID.binarycookies"
+assert_gone "macOS: Cookies/$BID.binarycookies removed"      "$H/Library/Cookies/$BID.binarycookies"
+assert_gone "macOS: Saved Application State removed"         "$H/Library/Saved Application State/$BID.savedState"
+assert_gone "macOS: Preferences/$BID.plist removed"          "$H/Library/Preferences/$BID.plist"
+assert_present "macOS: unrelated app cache kept"             "$H/Library/Caches/com.other.app/keepme"
+
+# ── 2. Linux: bundle-id-keyed XDG default paths are removed ──
+H=$(mktemp -d -p "$_TMP_ROOT")
+mkdir -p "$H/.cache/$BID" "$H/.local/share/$BID" "$H/.config/$BID" \
+         "$H/.local/state/$BID" "$H/.cache/other.app"
+run_uninstall "$H" Linux
+assert_gone "linux: ~/.cache/$BID removed"       "$H/.cache/$BID"
+assert_gone "linux: ~/.local/share/$BID removed" "$H/.local/share/$BID"
+assert_gone "linux: ~/.config/$BID removed"      "$H/.config/$BID"
+assert_gone "linux: ~/.local/state/$BID removed" "$H/.local/state/$BID"
+assert_present "linux: unrelated app cache kept" "$H/.cache/other.app"
+
+# ── 3. Linux: XDG_*_HOME overrides are honored ──
+H=$(mktemp -d -p "$_TMP_ROOT")
+XDG=$(mktemp -d -p "$_TMP_ROOT")
+mkdir -p "$XDG/cache/$BID" "$XDG/data/$BID" "$XDG/config/$BID" "$XDG/state/$BID"
+printf '#!/bin/sh\necho Linux\n' > "$STUB_BIN/uname"
+chmod +x "$STUB_BIN/uname"
+env -u UNSLOTH_STUDIO_HOME -u STUDIO_HOME \
+    XDG_CACHE_HOME="$XDG/cache" XDG_DATA_HOME="$XDG/data" \
+    XDG_CONFIG_HOME="$XDG/config" XDG_STATE_HOME="$XDG/state" \
+    HOME="$H" PATH="$STUB_BIN:$PATH" sh "$UNINSTALL_SH" >/dev/null 2>&1
+assert_gone "linux: XDG_CACHE_HOME override honored"  "$XDG/cache/$BID"
+assert_gone "linux: XDG_DATA_HOME override honored"   "$XDG/data/$BID"
+assert_gone "linux: XDG_CONFIG_HOME override honored" "$XDG/config/$BID"
+assert_gone "linux: XDG_STATE_HOME override honored"  "$XDG/state/$BID"
+
+# ── 4. Nothing to remove is a clean no-op (fresh HOME, exit 0) ──
+H=$(mktemp -d -p "$_TMP_ROOT")
+if run_uninstall "$H" Darwin; then
+    echo "  PASS: empty HOME -> no-op exit 0"; PASS=$((PASS+1))
+else
+    echo "  FAIL: empty HOME -> nonzero exit"; FAIL=$((FAIL+1))
+fi
+
+echo ""
+echo "Results: $PASS passed, $FAIL failed"
+[ "$FAIL" = 0 ]

tests/studio/playwright_ui_font_scale.py

@@ -38,7 +38,11 @@ def fail(m):
     raise AssertionError(f"[font-scale] FAIL: {m}")
 
 
-def near(a, b, tol = 0.35):
+def near(
+    a,
+    b,
+    tol = 0.35,
+):
     return a is not None and b is not None and abs(a - b) <= tol
 
 
@@ -86,9 +90,7 @@ def open_appearance(page):
         page.wait_for_timeout(700)
     if page.get_by_role("dialog").count() == 0:
         fail("settings dialog did not open")
-    page.get_by_role("dialog").get_by_role("button").filter(
-        has_text = "Appearance"
-    ).first.click()
+    page.get_by_role("dialog").get_by_role("button").filter(has_text = "Appearance").first.click()
     page.wait_for_timeout(600)
 
 
@@ -153,9 +155,7 @@ def main():
         page.wait_for_timeout(400)
 
         step("overflowing select scrolls its Radix viewport")
-        page.get_by_role("dialog").get_by_role("button").filter(
-            has_text = "Voice"
-        ).first.click()
+        page.get_by_role("dialog").get_by_role("button").filter(has_text = "Voice").first.click()
         page.wait_for_timeout(600)
         page.set_viewport_size({"width": 1440, "height": 480})
         page.locator("[aria-label='Dictation language']").click()
@@ -194,9 +194,7 @@ def main():
         page.wait_for_timeout(400)
 
         step("default restores exactly")
-        page.get_by_role("dialog").get_by_role("button").filter(
-            has_text = "Appearance"
-        ).first.click()
+        page.get_by_role("dialog").get_by_role("button").filter(has_text = "Appearance").first.click()
         page.wait_for_timeout(500)
         set_input(page, "UI font size", DEFAULT)
         final = measure(page)

tests/studio/test_ui_font_scale_contract.py

@@ -15,9 +15,7 @@ from pathlib import Path
 REPO = Path(__file__).resolve().parents[2]
 SRC = REPO / "studio/frontend/src"
 INDEX_CSS = (SRC / "index.css").read_text(encoding = "utf-8")
-STORE = (SRC / "features/settings/stores/appearance-custom-store.ts").read_text(
-    encoding = "utf-8"
-)
+STORE = (SRC / "features/settings/stores/appearance-custom-store.ts").read_text(encoding = "utf-8")
 SELECT = (SRC / "components/ui/select.tsx").read_text(encoding = "utf-8")
 
 # Raw numeric fontSize props are only allowed where a scaled stylesheet rule
@@ -70,9 +68,7 @@ def test_ui_token_families_exist():
 
 
 def test_explicit_code_font_size_is_never_multiplied():
-    match = re.search(
-        r"html\[data-code-font-size\][^{]*\{([^}]*)\}", INDEX_CSS
-    )
+    match = re.search(r"html\[data-code-font-size\][^{]*\{([^}]*)\}", INDEX_CSS)
     assert match is not None
     body = match.group(1)
     assert "var(--custom-code-font-size)" in body
@@ -83,7 +79,9 @@ def test_radix_select_viewport_owns_the_scroll_state():
     viewport = SELECT[SELECT.index("SelectPrimitive.Viewport") :]
     assert "overflow-y-auto" in viewport.split("</SelectPrimitive.Viewport>")[0]
     # The rounded surface itself must not scroll (WebKit squares its corners).
-    content_cls = re.search(r"SelectPrimitive\.Content[\s\S]*?className=\{cn\(\s*\"([^\"]+)\"", SELECT)
+    content_cls = re.search(
+        r"SelectPrimitive\.Content[\s\S]*?className=\{cn\(\s*\"([^\"]+)\"", SELECT
+    )
     assert content_cls is not None
     assert "overflow-hidden" in content_cls.group(1)
     assert "overflow-y-auto" not in content_cls.group(1)