Need fallback behaviour when dirs::download_dir returns None (#118)

src/base.rs

@@ -349,6 +349,9 @@ pub enum IambError {
     #[error("Serialization/deserialization error: {0}")]
     Serde(#[from] serde_json::Error),
 
+    #[error("No download directory configured")]
+    NoDownloadDir,
+
     #[error("Selected message does not have any attachments")]
     NoAttachment,
 

src/config.rs

@@ -319,7 +319,7 @@ impl Tunables {
 pub struct DirectoryValues {
     pub cache: PathBuf,
     pub logs: PathBuf,
-    pub downloads: PathBuf,
+    pub downloads: Option<PathBuf>,
 }
 
 #[derive(Clone, Default, Deserialize)]
@@ -354,10 +354,7 @@ impl Directories {
             dir
         });
 
-        let downloads = self
-            .downloads
-            .or_else(dirs::download_dir)
-            .expect("no dirs.downloads value configured!");
+        let downloads = self.downloads.or_else(dirs::download_dir);
 
         DirectoryValues { cache, logs, downloads }
     }

src/tests.rs

@@ -169,7 +169,7 @@ pub fn mock_dirs() -> DirectoryValues {
     DirectoryValues {
         cache: PathBuf::new(),
         logs: PathBuf::new(),
-        downloads: PathBuf::new(),
+        downloads: None,
     }
 }
 

src/windows/room/chat.rs

@@ -186,9 +186,10 @@ impl ChatState {
                 if let MessageEvent::Original(ev) = &msg.event {
                     let media = client.media();
 
-                    let mut filename = match filename {
-                        Some(f) => PathBuf::from(f),
-                        None => settings.dirs.downloads.clone(),
+                    let mut filename = match (filename, &settings.dirs.downloads) {
+                        (Some(f), _) => PathBuf::from(f),
+                        (None, Some(downloads)) => downloads.clone(),
+                        (None, None) => return Err(IambError::NoDownloadDir.into()),
                     };
 
                     let (source, msg_filename) = match &ev.content.msgtype {