Added canary asset

.gitattributes

@@ -9,6 +9,7 @@
 *.tar filter=lfs diff=lfs merge=lfs -text
 *.obj filter=lfs diff=lfs merge=lfs -text
 *.blend filter=lfs diff=lfs merge=lfs -text
+*.canary filter=lfs diff=lfs merge=lfs -text
 assets/world/map/*.bin filter=lfs diff=lfs merge=lfs -text
 
 *.ron gitlab-language=rust

common/assets/src/fs.rs

@@ -1,4 +1,4 @@
-use std::{borrow::Cow, io};
+use std::{borrow::Cow, fs, io};
 
 use assets_manager::{
     hot_reloading::{DynUpdateSender, EventSender, FsWatcherBuilder},
@@ -23,6 +23,18 @@ impl FileSystem {
                 .ok()
         });
 
+        let canary = fs::read_to_string(super::ASSETS_PATH.join("common").join("canary.canary"))
+            .map_err(|e| {
+                io::Error::new(
+                    io::ErrorKind::Other,
+                    format!("failed to load canary asset: {}", e),
+                )
+            })?;
+
+        if !canary.starts_with("VELOREN_CANARY_MAGIC") {
+            panic!("Canary asset `canary.canary` was present but did not contain the expected data. This *heavily* implies that you've not correctly set up Git LFS (Large File Storage). Visit `https://book.veloren.net/contributors/development-tools.html#git-lfs` for more information about setting up Git LFS.");
+        }
+
         Ok(Self {
             default,
             override_dir,

common/assets/src/lib.rs

@@ -305,6 +305,12 @@ mod tests {
     use std::{ffi::OsStr, fs::File};
     use walkdir::WalkDir;
 
+    #[test]
+    fn load_canary() {
+        // Loading the asset cache will automatically cause the canary to load
+        let _ = *super::ASSETS;
+    }
+
     /// Fail unless all `.ron` asset files successfully parse to `ron::Value`.
     #[test]
     fn parse_all_ron_files_to_value() {