fix(download): should not error when the model to be removed not exis…

…ted (#3296)

* fix: should not be error if file not found when newly download model

* chore: only check sha256 when model exists

crates/tabby-download/src/lib.rs

@@ -1,5 +1,5 @@
 //! Responsible for downloading ML models for use with tabby.
-use std::fs;
+use std::{fs, io};
 
 use aim_downloader::{bar::WrappedBar, error::DownloadError, hash::HashChecker, https};
 use anyhow::{bail, Result};
@@ -103,26 +103,35 @@ async fn download_model_impl(
         return Ok(());
     }
 
-    info!("Checking model integrity..");
+    if model_existed {
+        info!("Checking model integrity..");
 
-    let mut sha256_matched = true;
-    for (index, url) in urls.iter().enumerate() {
-        if HashChecker::check(partitioned_file_name!(index, urls.len()).as_str(), &url.1).is_err() {
-            sha256_matched = false;
-            break;
+        let mut sha256_matched = true;
+        for (index, url) in urls.iter().enumerate() {
+            if HashChecker::check(partitioned_file_name!(index, urls.len()).as_str(), &url.1)
+                .is_err()
+            {
+                sha256_matched = false;
+                break;
+            }
         }
-    }
 
-    if sha256_matched {
-        return Ok(());
-    }
+        if sha256_matched {
+            return Ok(());
+        }
 
-    warn!(
-        "Checksum doesn't match for <{}/{}>, re-downloading...",
-        registry.name, name
-    );
+        warn!(
+            "Checksum doesn't match for <{}/{}>, re-downloading...",
+            registry.name, name
+        );
+    }
 
-    fs::remove_dir_all(registry.get_model_dir(name))?;
+    match fs::remove_dir_all(registry.get_model_dir(name)) {
+        Ok(_) => Ok(()),
+        // Ignore "Not Found" error, when newly download, the model directory may not exist
+        Err(ref e) if e.kind() == io::ErrorKind::NotFound => Ok(()),
+        Err(e) => Err(e),
+    }?;
 
     // prepare for download
     let dir = registry.get_model_store_dir(name);