fix: correctly handle yaml templating

Author: DavSanchez

agent-control/src/agent_type/runtime_config/on_host/filesystem.rs

@@ -236,11 +236,18 @@ impl Templateable for TemplateableValue<DirEntriesMap> {
         let value: HashMap<SafePath, String> = if templated_string.is_empty() {
             HashMap::new()
         } else {
-            serde_yaml::from_str(&templated_string).map_err(|e| {
-                AgentTypeError::ValueNotParseableFromString(format!(
-                    "Could not parse templated directory items as YAML mapping: {e}"
-                ))
-            })?
+            let map_string_value: HashMap<SafePath, serde_yaml::Value> =
+                serde_yaml::from_str(&templated_string).map_err(|e| {
+                    AgentTypeError::ValueNotParseableFromString(format!(
+                        "Could not parse templated directory items as YAML: {e}"
+                    ))
+                })?;
+            // Convert the serde_yaml::Value (i.e. the file contents) to String
+
+            map_string_value
+                .into_iter()
+                .map(|(k, v)| Ok((k, output_string(v)?)))
+                .collect::<Result<HashMap<_, _>, serde_yaml::Error>>()?
         };
 
         Ok(Self {
@@ -250,6 +257,18 @@ impl Templateable for TemplateableValue<DirEntriesMap> {
     }
 }
 
+/// Converts a serde_yaml::Value to a String.
+/// If the value is already a String, it is returned as-is.
+/// Otherwise, it is serialized to a YAML string using serde_yaml.
+fn output_string(value: serde_yaml::Value) -> Result<String, serde_yaml::Error> {
+    match value {
+        // Pass the string directly (serde_yaml inserts literal syntax for multi-line strings)
+        serde_yaml::Value::String(s) => Ok(s),
+        // Else serialize the value to a YAML string using the default methods
+        v => serde_yaml::to_string(&v),
+    }
+}
+
 /// Validates that a file entry path is relative and does not escape its base directory.
 /// Returns a comma-separated list of error messages, if any.
 fn validate_file_entry_path(path: &Path) -> Result<(), String> {

agent-control/tests/on_host/scenarios/filesystem_ops.rs

@@ -128,6 +128,7 @@ fn complete_render_and_and_write_files_and_dirs() {
         "file4.txt",
         format!("File 4 contents with a variable: {string_var_content}\n"),
     );
+    let expected_dir_file5 = ("file5.yaml", "my_key: my_value\nmy_seq:\n- item1\n- item2\nmy_string: |-\n  This is a multi-line\n  string in YAML\n".to_string());
 
     // Create agent type definition
     create_file(
@@ -192,6 +193,14 @@ some_mapstringyaml:
   file3.txt: "File 3 contents"
   file4.txt: |
     File 4 contents with a variable: {string_var_content}
+  file5.yaml:
+    my_key: my_value
+    my_seq:
+        - item1
+        - item2
+    my_string: |-
+        This is a multi-line
+        string in YAML
 "#
         ),
         local_dir.to_path_buf(),
@@ -248,6 +257,10 @@ some_mapstringyaml:
             fully_templated_dir_search_path.join(expected_dir_file4.0),
             expected_dir_file4.1,
         ),
+        (
+            fully_templated_dir_search_path.join(expected_dir_file5.0),
+            expected_dir_file5.1,
+        ),
     ];
 
     retry(30, Duration::from_secs(1), || {