From 74c9b5f1b3f8aa325be07430250c76fbaee66165 Mon Sep 17 00:00:00 2001
From: Peter Edge <peter.edge@10xgenomics.com>
Date: Thu, 7 Mar 2024 19:35:15 -0800
Subject: [PATCH] Default to empty string in the case of missing doc comment

---
 martian-derive/src/lib.rs                | 8 +-------
 martian-derive/tests/mro/test_struct.mro | 2 +-
 martian-derive/tests/test_full_mro.rs    | 1 +
 3 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/martian-derive/src/lib.rs b/martian-derive/src/lib.rs
index aeeb962584..87d1cf126e 100644
--- a/martian-derive/src/lib.rs
+++ b/martian-derive/src/lib.rs
@@ -563,13 +563,7 @@ pub fn martian_struct(item: proc_macro::TokenStream) -> proc_macro::TokenStream
         };
 
         if mro_filename.is_some() && doc_comment.is_none() {
-            return syn::Error::new_spanned(field,
-            "ERROR: mro_filename attribute was specified for field but a doc comment was not defined for the field. \
-            mro_filename can only be specified when a doc comment is specified for a field, \
-            because doc comments are converted into Martian struct field descriptions which precede \
-            the Martian filename column (optional 3rd and 4th columns in Martian struct def)")
-                .to_compile_error()
-                .into();
+            doc_comment = Some("".to_string());
         }
 
         let doc_comment_code = match doc_comment {
diff --git a/martian-derive/tests/mro/test_struct.mro b/martian-derive/tests/mro/test_struct.mro
index 6af8b0a7d4..f9543f3909 100644
--- a/martian-derive/tests/mro/test_struct.mro
+++ b/martian-derive/tests/mro/test_struct.mro
@@ -21,7 +21,7 @@ struct Config(
 struct ChemistryDef(
     string name           "The chemistry name",
     string barcode_read,
-    int    barcode_length,
+    int    barcode_length ""                   "the_bc_length",
 )
 
 struct RnaChunk(
diff --git a/martian-derive/tests/test_full_mro.rs b/martian-derive/tests/test_full_mro.rs
index c3267ed7cb..e1ba276bb9 100644
--- a/martian-derive/tests/test_full_mro.rs
+++ b/martian-derive/tests/test_full_mro.rs
@@ -424,6 +424,7 @@ fn test_with_struct() {
         /// The chemistry name
         name: String,
         barcode_read: String,
+        #[mro_filename = "the_bc_length"]
         barcode_length: u8,
     }