Future is not send.

src/command/build/runner.rs

@@ -61,7 +61,7 @@ async fn get_output_directory(config: &Config) -> Result<PathBuf, CustomError> {
     Ok(output_directory)
 }
 
-fn filter_to_post_directories(entry: &DirEntry) -> Result<bool, CustomError> {
+async fn filter_to_post_directories(entry: &DirEntry) -> Result<bool, CustomError> {
     Ok(true)
 }
 

src/command/build/walk_fs.rs

@@ -1,3 +1,4 @@
+use std::future::Future;
 use std::ops::AsyncFn;
 use std::path::Path;
 
@@ -9,7 +10,10 @@ use crate::error::CustomError;
 
 pub(crate) fn walk_fs<'p, P: AsRef<Path> + std::marker::Send + 'p>(
     root: P,
-    predicate: fn(&DirEntry) -> Result<bool, CustomError>,
+    predicate: impl AsyncFn(&DirEntry) -> Result<bool, CustomError>
+        + std::marker::Send
+        + 'p
+        + std::marker::Copy,
 ) -> BoxFuture<'p, Result<Vec<DirEntry>, CustomError>> {
     async move {
         let mut ret = Vec::new();
@@ -20,7 +24,7 @@ pub(crate) fn walk_fs<'p, P: AsRef<Path> + std::marker::Send + 'p>(
                 let child_entries = walk_fs(entry.path(), predicate).await?;
                 ret.extend(child_entries);
             }
-            if predicate(&entry)? {
+            if predicate(&entry).await? {
                 ret.push(entry);
             }
         }