fix: reject relative complete_dir/incomplete_dir in SABnzbd import

apps/rustnzb/src/handlers.rs

@@ -2062,6 +2062,27 @@ pub async fn h_setup_apply(
         }
     }
 
+    // Reject relative complete_dir/incomplete_dir rather than silently persisting
+    // them: SABnzbd allows relative paths (resolved against its own working
+    // directory), but rustnzb creates these directories eagerly at startup via
+    // create_dir_all, which resolves a relative path against *its* process CWD
+    // (e.g. "/" in Docker) instead of the intended download volume — producing
+    // a confusing crash far away from the actual misconfiguration (see #62).
+    if let Some(ref dir) = preview.general.complete_dir
+        && !std::path::Path::new(dir).is_absolute()
+    {
+        return Err(ApiError::bad_request(
+            "cannot apply: complete_dir must be an absolute path",
+        ));
+    }
+    if let Some(ref dir) = preview.general.incomplete_dir
+        && !std::path::Path::new(dir).is_absolute()
+    {
+        return Err(ApiError::bad_request(
+            "cannot apply: incomplete_dir must be an absolute path",
+        ));
+    }
+
     let mut config = (*state.config()).clone();
 
     // Convert imported servers → ServerConfig with fresh UUIDs

apps/rustnzb/tests/sabnzbd_import_apply_test.rs

@@ -0,0 +1,127 @@
+//! Regression tests for the SABnzbd import apply path (issue #62 follow-up):
+//! a relative complete_dir/incomplete_dir must be rejected at apply time,
+//! not silently written to config.toml where it later causes a confusing
+//! startup crash.
+
+use std::sync::Arc;
+
+use arc_swap::ArcSwap;
+use axum::Json;
+use axum::extract::State;
+use http::StatusCode;
+use nzb_web::auth::{CredentialStore, TokenStore};
+use nzb_web::log_buffer::LogBuffer;
+use nzb_web::nzb_core::config::AppConfig;
+use nzb_web::nzb_core::db::Database;
+use nzb_web::nzb_core::sabnzbd_import::SabnzbdImportPreview;
+use nzb_web::queue_manager::QueueManager;
+use nzb_web::state::AppState;
+use rustnzb::handlers::h_setup_apply;
+
+fn test_state() -> (Arc<AppState>, tempfile::TempDir) {
+    let tempdir = tempfile::tempdir().expect("tempdir");
+    let log_buffer = LogBuffer::default();
+    let manager = QueueManager::new(
+        Vec::new(),
+        Database::open_memory().expect("database"),
+        tempdir.path().join("incomplete"),
+        tempdir.path().join("complete"),
+        log_buffer.clone(),
+        1,
+        Vec::new(),
+        0,
+        0,
+        false,
+        5,
+        false,
+        false,
+        100.0,
+        30,
+    );
+    let state = AppState::new(
+        Arc::new(ArcSwap::from_pointee(AppConfig::default())),
+        tempdir.path().join("config.toml"),
+        manager,
+        log_buffer,
+        Arc::new(TokenStore::new()),
+        Arc::new(CredentialStore::new(tempdir.path().to_path_buf())),
+    );
+    (Arc::new(state), tempdir)
+}
+
+fn preview_with_dirs(complete_dir: &str, incomplete_dir: &str) -> SabnzbdImportPreview {
+    serde_json::from_value(serde_json::json!({
+        "servers": [],
+        "categories": [],
+        "general": {
+            "api_key": null,
+            "complete_dir": complete_dir,
+            "incomplete_dir": incomplete_dir,
+            "speed_limit_bps": 0
+        },
+        "rss_feeds": [],
+        "warnings": [],
+        "skipped_fields": []
+    }))
+    .expect("preview JSON should deserialize")
+}
+
+/// Negative: a relative complete_dir must be rejected, not persisted.
+#[tokio::test]
+async fn apply_rejects_relative_complete_dir() {
+    let (state, _tempdir) = test_state();
+    let preview = preview_with_dirs("Downloads", "/downloads/incomplete");
+
+    let error = match h_setup_apply(State(state.clone()), Json(preview)).await {
+        Ok(_) => panic!("expected relative complete_dir to be rejected"),
+        Err(e) => e,
+    };
+
+    assert_eq!(error.status(), StatusCode::BAD_REQUEST);
+    assert!(error.to_string().contains("complete_dir"));
+    assert_eq!(
+        state.config().general.complete_dir,
+        AppConfig::default().general.complete_dir,
+        "rejected apply must not have mutated the persisted config"
+    );
+}
+
+/// Negative: a relative incomplete_dir must be rejected, not persisted.
+#[tokio::test]
+async fn apply_rejects_relative_incomplete_dir() {
+    let (state, _tempdir) = test_state();
+    let preview = preview_with_dirs("/downloads/complete", "Downloads/incomplete");
+
+    let error = match h_setup_apply(State(state.clone()), Json(preview)).await {
+        Ok(_) => panic!("expected relative incomplete_dir to be rejected"),
+        Err(e) => e,
+    };
+
+    assert_eq!(error.status(), StatusCode::BAD_REQUEST);
+    assert!(error.to_string().contains("incomplete_dir"));
+    assert_eq!(
+        state.config().general.incomplete_dir,
+        AppConfig::default().general.incomplete_dir,
+        "rejected apply must not have mutated the persisted config"
+    );
+}
+
+/// Positive: absolute complete_dir/incomplete_dir are applied normally.
+#[tokio::test]
+async fn apply_accepts_absolute_dirs() {
+    let (state, _tempdir) = test_state();
+    let preview = preview_with_dirs("/downloads/complete", "/downloads/incomplete");
+
+    h_setup_apply(State(state.clone()), Json(preview))
+        .await
+        .expect("absolute dirs should be accepted");
+
+    assert_eq!(
+        state.config().general.complete_dir,
+        std::path::PathBuf::from("/downloads/complete")
+    );
+    assert_eq!(
+        state.config().general.incomplete_dir,
+        std::path::PathBuf::from("/downloads/incomplete")
+    );
+}

crates/nzb-core/src/sabnzbd_import.rs

@@ -79,6 +79,28 @@ pub struct ImportedGeneral {
 // Helpers
 // ---------------------------------------------------------------------------
 
+/// Warn when an imported complete_dir/incomplete_dir isn't an absolute path.
+/// rustnzb creates these directories eagerly at startup via `create_dir_all`,
+/// which resolves a relative path against the process's working directory
+/// rather than any intended download volume — applying such a path produces
+/// a confusing crash far from the actual misconfiguration (see issue #62).
+fn warn_relative_dirs(general: &ImportedGeneral, warnings: &mut Vec<String>) {
+    if let Some(ref dir) = general.complete_dir
+        && !std::path::Path::new(dir).is_absolute()
+    {
+        warnings.push(format!(
+            "complete_dir '{dir}' is a relative path and must be made absolute before this import can be applied"
+        ));
+    }
+    if let Some(ref dir) = general.incomplete_dir
+        && !std::path::Path::new(dir).is_absolute()
+    {
+        warnings.push(format!(
+            "incomplete_dir '{dir}' is a relative path and must be made absolute before this import can be applied"
+        ));
+    }
+}
+
 /// Parse SABnzbd bandwidth limit string (e.g. "50M", "1G", "500K", "0", "").
 pub fn parse_bandwidth_limit(s: &str) -> u64 {
     let s = s.trim().trim_matches('"');
@@ -188,6 +210,7 @@ pub fn parse_sabnzbd_ini(content: &str) -> SabnzbdImportPreview {
             .map(|s| parse_bandwidth_limit(s))
             .unwrap_or(0),
     };
+    warn_relative_dirs(&general, &mut warnings);
 
     // --- Servers (from [servers] → [[name]]) ---
     let servers: Vec<ImportedServer> = sections
@@ -313,6 +336,7 @@ pub fn parse_sabnzbd_api_response(json: &serde_json::Value) -> SabnzbdImportPrev
             .or_else(|| misc["bandwidth_limit"].as_u64())
             .unwrap_or(0),
     };
+    warn_relative_dirs(&general, &mut warnings);
 
     // --- Servers ---
     let servers: Vec<ImportedServer> = config["servers"]
@@ -548,6 +572,77 @@ mod tests {
         assert_eq!(preview.warnings.len(), 1);
     }
 
+    #[test]
+    fn ini_import_warns_on_relative_complete_and_incomplete_dir() {
+        let preview = parse_sabnzbd_ini(
+            r#"
+            [misc]
+            complete_dir = Downloads
+            download_dir = Downloads/incomplete
+            "#,
+        );
+
+        assert!(
+            preview
+                .warnings
+                .iter()
+                .any(|w| w.contains("complete_dir") && w.contains("Downloads")),
+            "expected a relative complete_dir warning, got: {:?}",
+            preview.warnings
+        );
+        assert!(
+            preview
+                .warnings
+                .iter()
+                .any(|w| w.contains("incomplete_dir") && w.contains("Downloads/incomplete")),
+            "expected a relative incomplete_dir warning, got: {:?}",
+            preview.warnings
+        );
+    }
+
+    #[test]
+    fn ini_import_does_not_warn_on_absolute_complete_and_incomplete_dir() {
+        let preview = parse_sabnzbd_ini(
+            r#"
+            [misc]
+            complete_dir = /downloads/complete
+            download_dir = /downloads/incomplete
+            "#,
+        );
+
+        assert!(
+            preview.warnings.is_empty(),
+            "expected no warnings for absolute dirs, got: {:?}",
+            preview.warnings
+        );
+    }
+
+    #[test]
+    fn api_import_warns_on_relative_complete_and_incomplete_dir() {
+        let preview = parse_sabnzbd_api_response(&serde_json::json!({
+            "config": {
+                "misc": { "complete_dir": "Downloads", "download_dir": "Downloads/incomplete" }
+            }
+        }));
+
+        assert!(
+            preview
+                .warnings
+                .iter()
+                .any(|w| w.contains("complete_dir") && w.contains("Downloads")),
+            "expected a relative complete_dir warning, got: {:?}",
+            preview.warnings
+        );
+        assert!(
+            preview
+                .warnings
+                .iter()
+                .any(|w| w.contains("incomplete_dir") && w.contains("Downloads/incomplete")),
+            "expected a relative incomplete_dir warning, got: {:?}",
+            preview.warnings
+        );
+    }
+
     proptest! {
         #[test]
         fn arbitrary_ini_input_never_panics(input in ".{0,4096}") {