Merge branch 'fix-374-startup-drive-walk' into integ-b7

apps/lightcraft/src/main.rs

@@ -469,6 +469,31 @@ ENVIRONMENT:
                    <settings folder>/logs/lightcraft.log (previous runs: lightcraft.1.log, lightcraft.2.log)
 ";
 
+/// The launch arguments' files and folders to import (absolute), and a notice for each one that
+/// is not imported (see [`lightcraft_engine::import::launch_path`]; issue #374).
+fn launch_imports(args: &[String]) -> (Vec<String>, Vec<String>) {
+    let cwd = std::env::current_dir().ok();
+    let home = std::env::var_os(if cfg!(windows) { "USERPROFILE" } else { "HOME" }).filter(|h| !h.is_empty()).map(std::path::PathBuf::from);
+    launch_imports_in(args, cwd.as_deref(), home.as_deref())
+}
+
+fn launch_imports_in(args: &[String], cwd: Option<&std::path::Path>, home: Option<&std::path::Path>) -> (Vec<String>, Vec<String>) {
+    use lightcraft_engine::import::{LaunchPath, launch_path};
+    let (mut files, mut notices) = (Vec::new(), Vec::new());
+    for a in args {
+        match launch_path(a, cwd, home, lightcraft_engine::devices::dcim_in) {
+            Some(LaunchPath::Import(p)) => files.push(p),
+            Some(LaunchPath::Refused { path, why }) => {
+                log::warn!("not importing {path} given at launch: {why}");
+                notices
+                    .push(format!("{path} was not imported: it is {why}. To import from it, choose a folder inside it with File ▸ Import Photos…"));
+            }
+            None => {}
+        }
+    }
+    (files, notices)
+}
+
 /// Where the log files live: `logs` in the settings folder, next to `ui.json` (see `logging`).
 /// None with `LIGHTCRAFT_NO_PREFS` (tests, scripts), so those runs don't rotate away the user's logs.
 fn log_dir() -> Option<std::path::PathBuf> {
@@ -541,6 +566,9 @@ fn main() -> eframe::Result {
             None => logger.no_file(),
         }
     }
+    // what the arguments name, resolved now: an empty or relative argument never becomes a drive
+    // root, and a whole drive or home folder is not walked (issue #374)
+    let (files, launch_notices) = launch_imports(&files);
     let (prefs, prefs_warning, keep_prefs_file) = load_prefs(in_memory);
     // the saved language from the start, so a failed start is reported in it too
     if let Some(ui) = &prefs {
@@ -593,6 +621,7 @@ fn main() -> eframe::Result {
             lightcraft_ui_egui::i18n::set_language(app.ui.language);
             app.integrated_titlebar = cfg!(target_os = "macos");
             app.notices.extend(prefs_warning);
+            app.notices.extend(launch_notices);
             // what's on disk now: only changes are written
             let writer = PrefsWriter {
                 path: if in_memory { None } else { prefs_path() },
@@ -615,7 +644,12 @@ fn main() -> eframe::Result {
                 p.pending_import = files;
                 app.library_problem = Some(p);
             } else if !files.is_empty() {
-                let _ = app.run("library.import", serde_json::json!({"paths": files}));
+                // listed and read on the import worker once the window shows (issue #374: never
+                // here, before the first frame, where a large folder kept the window from
+                // appearing)
+                if let Err(e) = lightcraft_ui_egui::import::start_paths(&mut app, files) {
+                    log::warn!("import at launch: {e}");
+                }
                 app.ui.view = lightcraft_ui_egui::state::ViewMode::PhotoGrid;
             }
             // native menu bar generated from the command registry (macOS; elsewhere the menus are
@@ -665,6 +699,24 @@ mod tests {
         d
     }
 
+    /// Issue #374: launch arguments that would walk a whole drive or home folder are reported,
+    /// not imported; empty ones are ignored; the rest are imported as absolute paths.
+    #[test]
+    fn launch_arguments_never_walk_a_drive_or_the_home_folder() {
+        let home = dir("launch");
+        std::fs::create_dir_all(home.join("Trip")).unwrap();
+        let args: Vec<String> = ["", "  ", ".", "Trip", &home.to_string_lossy()].iter().map(|s| s.to_string()).collect();
+        let (files, notices) = launch_imports_in(&args, Some(&home), Some(&home));
+        assert_eq!(files, [home.join("Trip").to_string_lossy().to_string()]);
+        assert_eq!(notices.len(), 2, "{notices:?}");
+        assert!(notices.iter().all(|n| n.contains("was not imported")), "{notices:?}");
+        // the working folder is a drive root (a launcher's choice): `.` is never the whole drive
+        let root = home.ancestors().last().unwrap().to_path_buf();
+        let (files, notices) = launch_imports_in(&[".".to_string()], Some(&root), None);
+        assert!(files.iter().all(|f| f.ends_with("DCIM")) && files.len() + notices.len() == 1, "{files:?} {notices:?}");
+        let _ = std::fs::remove_dir_all(&home);
+    }
+
     /// Issue #103: a damaged ui.json (which holds the library location) is kept aside and
     /// reported, not silently replaced by the defaults.
     #[test]

crates/engine/src/cmd/lut_profiles.rs

@@ -41,22 +41,11 @@ fn cube_files(paths: &[String]) -> Vec<(String, String, Option<String>)> {
     for p in paths {
         let path = Path::new(p);
         if path.is_dir() {
-            let mut stack = vec![path.to_path_buf()];
-            while let Some(d) = stack.pop() {
-                let Ok(rd) = std::fs::read_dir(&d) else { continue };
-                for e in rd.flatten() {
-                    let ep = e.path();
-                    if ep.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.')) {
-                        continue;
-                    }
-                    if ep.is_dir() {
-                        stack.push(ep);
-                    } else if ep.extension().is_some_and(|x| x.eq_ignore_ascii_case("cube"))
-                        && let Ok(t) = std::fs::read_to_string(&ep)
-                    {
-                        let group = ep.parent().and_then(|d| d.file_name()).map(|n| n.to_string_lossy().to_string());
-                        out.push((ep.file_stem().map(|n| n.to_string_lossy().to_string()).unwrap_or_default(), t, group));
-                    }
+            let cube = |f: &Path| f.extension().is_some_and(|x| x.eq_ignore_ascii_case("cube"));
+            for ep in crate::walk::files_in(path, None, crate::walk::Limits::default(), cube).files {
+                if let Ok(t) = std::fs::read_to_string(&ep) {
+                    let group = ep.parent().and_then(|d| d.file_name()).map(|n| n.to_string_lossy().to_string());
+                    out.push((ep.file_stem().map(|n| n.to_string_lossy().to_string()).unwrap_or_default(), t, group));
                 }
             }
         } else if path.extension().is_some_and(|x| x.eq_ignore_ascii_case("zip")) {

crates/engine/src/devices.rs

@@ -191,7 +191,7 @@ pub fn devices_in(parents: &[std::path::PathBuf], extra: Vec<std::path::PathBuf>
 
 /// The volume's `DCIM` folder: the usual spellings are checked directly, so a volume's root is
 /// only listed (other spellings on a case-sensitive volume) off Windows, whose drives aren't.
-fn dcim_in(root: &std::path::Path) -> Option<std::path::PathBuf> {
+pub fn dcim_in(root: &std::path::Path) -> Option<std::path::PathBuf> {
     if let Some(p) = ["DCIM", "dcim"].iter().map(|n| root.join(n)).find(|p| p.is_dir()) {
         return Some(p);
     }

crates/engine/src/import.rs

@@ -317,32 +317,96 @@ pub fn is_supported(path: &Path) -> bool {
 }
 
 /// Expand files and folders (recursively) into supported files. `skip` (e.g. the library folder)
-/// is never descended into.
+/// is never descended into. Each folder's walk is bounded ([`crate::walk::Limits::default`]); a
+/// walk that stops at a bound is logged.
 pub fn expand(paths: &[String], skip: Option<&Path>) -> Vec<String> {
-    fn walk(p: &Path, skip: Option<&Path>, out: &mut Vec<String>, top: bool) {
-        let hidden = p.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.'));
-        if (hidden && !top) || skip.is_some_and(|s| p == s) {
-            return;
+    expand_within(paths, skip, crate::walk::Limits::default()).0
+}
+
+/// [`expand`] with the walk bounded by `limits` → (files, whether a walk stopped at a bound).
+pub fn expand_within(paths: &[String], skip: Option<&Path>, limits: crate::walk::Limits) -> (Vec<String>, bool) {
+    let mut out = Vec::new();
+    let mut truncated = false;
+    for p in paths {
+        let p = Path::new(p);
+        if skip.is_some_and(|s| p == s) {
+            continue;
         }
         if p.is_dir() {
-            let Ok(rd) = std::fs::read_dir(p) else { return };
-            let mut v: Vec<PathBuf> = rd.flatten().map(|e| e.path()).collect();
-            v.sort();
-            for c in v {
-                walk(&c, skip, out, false);
+            let w = crate::walk::files_in(p, skip, limits, is_supported);
+            if w.truncated {
+                log::warn!(
+                    "import: stopped looking in {} after {} entries (limits: {} entries, {} folder levels)",
+                    p.display(),
+                    w.entries,
+                    limits.max_entries,
+                    limits.max_depth
+                );
             }
-        } else if top || is_supported(p) {
+            truncated |= w.truncated;
+            out.extend(w.files.into_iter().map(|f| f.to_string_lossy().to_string()));
+        } else {
             // explicitly named files are attempted even with an unknown extension (sniffed)
             out.push(p.to_string_lossy().to_string());
         }
     }
-    let mut out = Vec::new();
-    for p in paths {
-        walk(Path::new(p), skip, &mut out, true);
-    }
     let mut seen = std::collections::HashSet::new();
     out.retain(|p| seen.insert(p.clone()));
-    out
+    (out, truncated)
+}
+
+/// What a path given on the command line at launch becomes ([`launch_path`]).
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum LaunchPath {
+    /// Import this (absolute) file or folder, in the background.
+    Import(String),
+    /// Not imported: `path` (absolute) is a whole drive or the whole home folder, which is never
+    /// walked without being chosen in the app (issue #374).
+    Refused { path: String, why: String },
+}
+
+/// Resolve a launch argument for importing (issue #374). An empty argument is ignored (`None`);
+/// a relative one (`.`, `..`, `photos`; `/` or `\` on Windows, the current drive's root) is
+/// resolved against `cwd` — the working folder a launcher picked, often a drive root or
+/// `C:\Windows\System32` — and refused when that leaves no folder (`cwd` unknown). A drive
+/// or file-system root is replaced by its camera folder (`DCIM`, from `dcim`: a memory card) or
+/// refused, and so is the home folder `home`: either would walk most of the disk.
+pub fn launch_path(arg: &str, cwd: Option<&Path>, home: Option<&Path>, dcim: impl Fn(&Path) -> Option<PathBuf>) -> Option<LaunchPath> {
+    if arg.trim().is_empty() {
+        return None;
+    }
+    let given = Path::new(arg);
+    let joined = if given.is_absolute() {
+        given.to_path_buf()
+    } else {
+        match cwd {
+            Some(c) => c.join(given),
+            None => return Some(LaunchPath::Refused { path: arg.to_string(), why: "a relative path, and the working folder is unknown".into() }),
+        }
+    };
+    // `.` and `..` resolved by name (no file-system access)
+    let mut abs = PathBuf::new();
+    for c in joined.components() {
+        match c {
+            std::path::Component::CurDir => {}
+            std::path::Component::ParentDir => {
+                abs.pop();
+            }
+            other => abs.push(other.as_os_str()),
+        }
+    }
+    let shown = abs.to_string_lossy().to_string();
+    if abs.parent().is_none() {
+        return Some(match dcim(&abs) {
+            Some(d) => LaunchPath::Import(d.to_string_lossy().to_string()),
+            None => LaunchPath::Refused { path: shown, why: "a whole drive".into() },
+        });
+    }
+    let key = lightcraft_catalog::query::folder_key;
+    if home.is_some_and(|h| key(&h.to_string_lossy()) == key(&shown)) {
+        return Some(LaunchPath::Refused { path: shown, why: "the whole home folder".into() });
+    }
+    Some(LaunchPath::Import(shown))
 }
 
 /// Probe files (headers + content hash) as an import would.

crates/engine/src/lib.rs

@@ -42,6 +42,7 @@ pub mod segment;
 pub mod sidecar;
 pub mod smart;
 mod view;
+pub mod walk;
 
 use std::sync::Arc;
 

crates/engine/src/presets.rs

@@ -83,28 +83,22 @@ pub fn parse_preset_file(name: &str, bytes: &[u8]) -> Result<Vec<Preset>, String
     Ok(out)
 }
 
-/// Expand files/folders (recursively) into preset files (`.lcpreset`, `.xmp`).
+/// Expand files/folders (recursively, bounded: see [`crate::walk`]) into preset files
+/// (`.lcpreset`, `.xmp`).
 pub fn expand_preset_paths(paths: &[String]) -> Vec<String> {
-    fn walk(p: &Path, out: &mut Vec<String>, top: bool) {
-        if p.is_dir() {
-            let Ok(rd) = std::fs::read_dir(p) else { return };
-            let mut v: Vec<_> = rd.flatten().map(|e| e.path()).collect();
-            v.sort();
-            for c in v {
-                if !c.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.')) {
-                    walk(&c, out, false);
-                }
-            }
-        } else {
-            let ext = p.extension().map(|e| e.to_string_lossy().to_ascii_lowercase()).unwrap_or_default();
-            if top || ext == LCPRESET_EXT || ["xmp", "lrtemplate", "zip", "lmp", "mplumpack"].contains(&ext.as_str()) {
-                out.push(p.to_string_lossy().to_string());
-            }
-        }
-    }
+    let preset_file = |p: &Path| {
+        let ext = p.extension().map(|e| e.to_string_lossy().to_ascii_lowercase()).unwrap_or_default();
+        ext == LCPRESET_EXT || ["xmp", "lrtemplate", "zip", "lmp", "mplumpack"].contains(&ext.as_str())
+    };
     let mut out = Vec::new();
     for p in paths {
-        walk(Path::new(p), &mut out, true);
+        let path = Path::new(p);
+        if path.is_dir() {
+            let w = crate::walk::files_in(path, None, crate::walk::Limits::default(), preset_file);
+            out.extend(w.files.into_iter().map(|f| f.to_string_lossy().to_string()));
+        } else {
+            out.push(p.clone());
+        }
     }
     out
 }

crates/engine/src/tests_import.rs

@@ -1007,3 +1007,58 @@ fn trashed_photo_ids(tag: &str) -> (Session, std::path::PathBuf, [u64; 1], u64)
     let (s, src, id) = trashed_photo(tag);
     (s, src, [id], 0)
 }
+
+/// Issue #374: launch arguments never turn into a walk of a whole drive or home folder. An empty
+/// argument is ignored; `.`, `..` and (on Windows) `/` are resolved against the working folder a
+/// launcher picked, which is often a drive root; a root is replaced by its memory card's DCIM
+/// folder or refused, and so is the home folder.
+#[test]
+fn launch_paths_never_become_a_drive_root_or_the_home_folder() {
+    use crate::import::{LaunchPath, launch_path};
+    let root = if cfg!(windows) { Path::new("C:\\") } else { Path::new("/") };
+    let home = if cfg!(windows) { Path::new("C:\\Users\\me") } else { Path::new("/home/me") };
+    let none = |_: &Path| None;
+    let refused = |r: Option<LaunchPath>| matches!(r, Some(LaunchPath::Refused { .. }));
+    for empty in ["", "  "] {
+        assert_eq!(launch_path(empty, Some(root), Some(home), none), None, "{empty:?}");
+    }
+    // the working folder is the drive root: `.` (and `..`) name the whole drive
+    for arg in [".", "..", "./", ".\\..", "/"] {
+        let arg = if cfg!(windows) { arg.to_string() } else { arg.replace('\\', "/") };
+        assert!(refused(launch_path(&arg, Some(root), Some(home), none)), "{arg:?}");
+    }
+    assert!(refused(launch_path("..", Some(&home.join("Pictures")), Some(home), none)), "up to the home folder");
+    assert!(refused(launch_path(&home.to_string_lossy(), None, Some(home), none)));
+    assert!(refused(launch_path(".", None, Some(home), none)), "relative, no working folder");
+    // a memory card's root: its camera folder
+    let dcim = |r: &Path| Some(r.join("DCIM"));
+    assert_eq!(launch_path(".", Some(root), Some(home), dcim), Some(LaunchPath::Import(root.join("DCIM").to_string_lossy().to_string())));
+    // ordinary folders and files resolve to absolute paths
+    let pics = home.join("Pictures");
+    assert_eq!(launch_path("Pictures", Some(home), Some(home), none), Some(LaunchPath::Import(pics.to_string_lossy().to_string())));
+    assert_eq!(
+        launch_path(&pics.join("a.jpg").to_string_lossy(), None, Some(home), none),
+        Some(LaunchPath::Import(pics.join("a.jpg").to_string_lossy().to_string()))
+    );
+}
+
+/// Issue #374: a folder import is bounded — a tree deeper or larger than the limits is not walked
+/// to the end (it stops and says so), and what it found is still returned.
+#[test]
+fn expand_stops_at_the_walk_limits() {
+    let d = temp_dir("bounded");
+    let mut deep = d.clone();
+    for i in 0..8 {
+        deep = deep.join(format!("d{i}"));
+        std::fs::create_dir_all(&deep).unwrap();
+        std::fs::write(deep.join(format!("p{i}.jpg")), b"x").unwrap();
+    }
+    let top = [d.to_string_lossy().to_string()];
+    let (all, cut) = crate::import::expand_within(&top, None, crate::walk::Limits::default());
+    assert_eq!((all.len(), cut), (8, false));
+    let (some, cut) = crate::import::expand_within(&top, None, crate::walk::Limits { max_depth: 3, max_entries: 1000 });
+    assert_eq!((some.len(), cut), (2, true), "{some:?}");
+    let (few, cut) = crate::import::expand_within(&top, None, crate::walk::Limits { max_depth: 32, max_entries: 5 });
+    assert!(cut && few.len() < 8, "{few:?}");
+    let _ = std::fs::remove_dir_all(&d);
+}

crates/engine/src/walk.rs

@@ -0,0 +1,183 @@
+//! Bounded folder walks (issue #374): every recursive listing of the disk — import, Local's
+//! Include Subfolders, Find Missing Photos, preset and LUT folders, MCP — goes through
+//! [`files_in`], which stops at a depth and a number of directory entries instead of walking a
+//! whole drive, follows a symbolic link or junction to a folder at most once (no loops), and
+//! decides what is a folder from the directory listing itself (no extra open per entry, which
+//! is what makes a large walk slow on Windows).
+//!
+//! It never chooses where to walk: callers pass a folder the user named. Nothing in the app walks
+//! at startup or on the UI thread.
+
+use std::collections::HashSet;
+use std::path::{Path, PathBuf};
+
+/// How far a walk may go.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Limits {
+    /// Folder levels below the starting folder that are listed (its own entries are level 1).
+    pub max_depth: usize,
+    /// Directory entries looked at in all (files and folders, hidden ones included).
+    pub max_entries: usize,
+}
+
+impl Default for Limits {
+    fn default() -> Self {
+        Limits { max_depth: MAX_DEPTH, max_entries: MAX_ENTRIES }
+    }
+}
+
+/// Folder levels a walk descends at most; photo trees are a handful of levels deep.
+pub const MAX_DEPTH: usize = 32;
+/// Directory entries a walk looks at at most: far more than any photo folder holds, far fewer
+/// than a whole system drive.
+pub const MAX_ENTRIES: usize = 1_000_000;
+
+/// What a walk found.
+#[derive(Debug, Default, PartialEq)]
+pub struct Walked {
+    /// The files `keep` accepted, in path order, folder by folder (depth first).
+    pub files: Vec<PathBuf>,
+    /// The walk stopped at a [`Limits`] bound: there may be more files.
+    pub truncated: bool,
+    /// Directory entries looked at.
+    pub entries: usize,
+}
+
+fn hidden(p: &Path) -> bool {
+    p.file_name().is_some_and(|n| n.to_string_lossy().starts_with('.'))
+}
+
+/// The files below folder `root` that `keep` accepts. Hidden entries (names starting with `.`)
+/// are left out, the folder `skip` (e.g. the library's own) is never entered, and the walk stops
+/// at `limits` (see [`Walked::truncated`]). Unreadable folders are skipped.
+pub fn files_in(root: &Path, skip: Option<&Path>, limits: Limits, mut keep: impl FnMut(&Path) -> bool) -> Walked {
+    let mut out = Walked::default();
+    // canonical folders reached through a link, so a link loop is walked at most once
+    let mut linked: HashSet<PathBuf> = HashSet::new();
+    if let Ok(c) = std::fs::canonicalize(root) {
+        linked.insert(c);
+    }
+    // (path, depth of the folder it is in, is a folder); popped in path order
+    let mut stack: Vec<(PathBuf, usize, bool)> = vec![(root.to_path_buf(), 0, true)];
+    while let Some((path, depth, is_dir)) = stack.pop() {
+        if !is_dir {
+            if keep(&path) {
+                out.files.push(path);
+            }
+            continue;
+        }
+        if skip.is_some_and(|s| path == s) {
+            continue;
+        }
+        if depth >= limits.max_depth {
+            out.truncated = true;
+            continue;
+        }
+        let Ok(rd) = std::fs::read_dir(&path) else { continue };
+        let mut children: Vec<(PathBuf, bool)> = Vec::new();
+        for e in rd.flatten() {
+            if out.entries >= limits.max_entries {
+                out.truncated = true;
+                break;
+            }
+            out.entries = out.entries.saturating_add(1);
+            let p = e.path();
+            if hidden(&p) {
+                continue;
+            }
+            let Ok(ft) = e.file_type() else { continue };
+            let dir = if ft.is_symlink() {
+                // a link (or a Windows junction): a folder is entered once, a file is a file
+                match std::fs::metadata(&p) {
+                    Ok(m) if m.is_dir() => {
+                        let Ok(c) = std::fs::canonicalize(&p) else { continue };
+                        if !linked.insert(c) {
+                            continue;
+                        }
+                        true
+                    }
+                    _ => false,
+                }
+            } else {
+                ft.is_dir()
+            };
+            children.push((p, dir));
+        }
+        children.sort();
+        let below = depth.saturating_add(1);
+        stack.extend(children.into_iter().rev().map(|(p, d)| (p, below, d)));
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn tmp(tag: &str) -> PathBuf {
+        let d = std::env::temp_dir().join(format!("lc-walk-{tag}-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&d);
+        std::fs::create_dir_all(&d).unwrap();
+        d
+    }
+
+    #[test]
+    fn files_come_in_path_order_without_hidden_ones_or_the_skipped_folder() {
+        let d = tmp("order");
+        for f in ["b/2.jpg", "a/1.jpg", "a/x/0.jpg", "c.jpg", ".hidden/h.jpg", "a/.h.jpg", "lib/l.jpg", "a/n.txt"] {
+            let p = d.join(f);
+            std::fs::create_dir_all(p.parent().unwrap()).unwrap();
+            std::fs::write(p, b"x").unwrap();
+        }
+        let lib = d.join("lib");
+        let w = files_in(&d, Some(&lib), Limits::default(), |p| p.extension().is_some_and(|e| e == "jpg"));
+        let rel: Vec<String> = w.files.iter().map(|p| p.strip_prefix(&d).unwrap().to_string_lossy().replace('\\', "/")).collect();
+        assert_eq!(rel, ["a/1.jpg", "a/x/0.jpg", "b/2.jpg", "c.jpg"]);
+        assert!(!w.truncated);
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
+    /// Issue #374: a walk never runs on without end — a tree deeper than the limit, or with more
+    /// entries than the limit, stops and says so.
+    #[test]
+    fn deep_and_wide_trees_stop_at_the_limits() {
+        let d = tmp("bounds");
+        let mut deep = d.join("deep");
+        for i in 0..12 {
+            deep = deep.join(format!("l{i}"));
+        }
+        std::fs::create_dir_all(&deep).unwrap();
+        std::fs::write(deep.join("bottom.jpg"), b"x").unwrap();
+        let wide = d.join("wide");
+        std::fs::create_dir_all(&wide).unwrap();
+        for i in 0..50 {
+            std::fs::write(wide.join(format!("{i:02}.jpg")), b"x").unwrap();
+        }
+        let all = |_: &Path| true;
+        let w = files_in(&d.join("deep"), None, Limits { max_depth: 5, max_entries: 1000 }, all);
+        assert!(w.files.is_empty() && w.truncated, "{w:?}");
+        let w = files_in(&d.join("deep"), None, Limits { max_depth: 13, max_entries: 1000 }, all);
+        assert_eq!((w.files.len(), w.truncated), (1, false), "{w:?}");
+        let w = files_in(&wide, None, Limits { max_depth: 5, max_entries: 20 }, all);
+        assert_eq!((w.files.len(), w.entries, w.truncated), (20, 20, true));
+        let w = files_in(&wide, None, Limits::default(), all);
+        assert_eq!((w.files.len(), w.truncated), (50, false));
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
+    /// A link back up the tree (a loop) is followed at most once: the walk ends.
+    #[cfg(unix)]
+    #[test]
+    fn link_loops_end() {
+        let d = tmp("loop");
+        std::fs::create_dir_all(d.join("a/b")).unwrap();
+        std::fs::write(d.join("a/b/p.jpg"), b"x").unwrap();
+        std::os::unix::fs::symlink(&d, d.join("a/b/up")).unwrap();
+        std::os::unix::fs::symlink(d.join("a"), d.join("alias")).unwrap();
+        let w = files_in(&d, None, Limits::default(), |_| true);
+        assert!(!w.truncated, "{w:?}");
+        assert!(w.files.len() <= 2, "{w:?}");
+        assert!(w.files.iter().any(|p| p.ends_with("a/b/p.jpg")), "{w:?}");
+        let _ = std::fs::remove_dir_all(&d);
+    }
+}

crates/mcp/src/headless.rs

@@ -139,31 +139,20 @@ impl Backend for Headless {
     }
 }
 
-/// Expand folders (recursively, sorted) into photo files and make paths absolute.
+/// Expand folders (recursively, sorted; bounded, see `lightcraft_engine::walk`) into photo files
+/// and make paths absolute.
 pub fn expand_paths(paths: &[String]) -> Vec<String> {
-    fn walk(p: &Path, out: &mut Vec<String>) {
-        if p.is_dir() {
-            if let Ok(rd) = std::fs::read_dir(p) {
-                let mut v: Vec<_> = rd.flatten().map(|e| e.path()).collect();
-                v.sort();
-                for c in v {
-                    if c.file_name().is_some_and(|n| !n.to_string_lossy().starts_with('.')) {
-                        walk(&c, out);
-                    }
-                }
-            }
-        } else if p.extension().is_some_and(|e| PHOTO_EXTENSIONS.contains(&e.to_string_lossy().to_lowercase().as_str())) {
-            out.push(std::path::absolute(p).unwrap_or_else(|_| p.to_path_buf()).to_string_lossy().to_string());
-        }
-    }
+    let absolute = |p: &Path| std::path::absolute(p).unwrap_or_else(|_| p.to_path_buf()).to_string_lossy().to_string();
+    let photo = |p: &Path| p.extension().is_some_and(|e| PHOTO_EXTENSIONS.contains(&e.to_string_lossy().to_lowercase().as_str()));
     let mut out = Vec::new();
     for p in paths {
         let path = Path::new(p);
         if path.is_dir() {
-            walk(path, &mut out);
+            let w = lightcraft_engine::walk::files_in(path, None, lightcraft_engine::walk::Limits::default(), photo);
+            out.extend(w.files.iter().map(|f| absolute(f)));
         } else {
             // Explicit files are kept even with unknown extensions (the probe decides).
-            out.push(std::path::absolute(path).unwrap_or_else(|_| path.to_path_buf()).to_string_lossy().to_string());
+            out.push(absolute(path));
         }
     }
     out

crates/ui-egui/src/panels/library_problem.rs

@@ -56,8 +56,11 @@ fn open(app: &mut LightcraftApp, path: Option<String>) {
         Ok(serde_json::Value::Null) => {} // folder dialog cancelled
         Ok(_) => {
             let files = app.library_problem.take().map(|p| p.pending_import).unwrap_or_default();
-            if !files.is_empty() {
-                let _ = app.run("library.import", json!({"paths": files}));
+            // in the background, like files dropped on the window (issue #374)
+            if !files.is_empty()
+                && let Err(e) = crate::import::start_paths(app, files)
+            {
+                log::warn!("import: {e}");
             }
         }
         Err(e) => {
@@ -144,8 +147,11 @@ pub fn show(app: &mut LightcraftApp, ctx: &egui::Context) {
                 p.dismissed = true;
             }
             let files = app.library_problem.as_mut().map(|p| std::mem::take(&mut p.pending_import)).unwrap_or_default();
-            if !files.is_empty() {
-                let _ = app.run("library.import", json!({"paths": files}));
+            // in the background, like files dropped on the window (issue #374)
+            if !files.is_empty()
+                && let Err(e) = crate::import::start_paths(app, files)
+            {
+                log::warn!("import: {e}");
             }
         }
         Some(Choice::Quit) => app.ui.quit = true,

crates/ui-egui/src/tests_library_problem.rs

@@ -75,6 +75,8 @@ fn unopenable_library_asks_instead_of_running_a_demo() {
     assert!(!has(&h, "button:libraryRetry"));
     assert!(has(&h, "indicator:temporarySession"));
     assert!(h.app.session.library.is_none());
+    // imported on the import worker (issue #374: never synchronously on the UI thread)
+    h.step_until(T, |h| h.app.import.is_none() && h.app.session.catalog.len() == 1);
     assert_eq!(h.app.session.catalog.len(), 1, "the command-line photo is imported into the temporary session");
     if let Some(p) = std::env::var_os("LIGHTCRAFT_TEST_SHOTS") {
         let r = h.request("ui.screenshot", json!({"path": std::path::Path::new(&p).join("banner.png").to_string_lossy(), "headless": true}), T);