fix: Copy sp1-helper binary build (#1279)

build/src/lib.rs

@@ -224,18 +224,25 @@ fn copy_elf_to_output_dir(
 
     // The ELF is written to a target folder specified by the program's package. If built with Docker,
     // includes /docker after HELPER_TARGET_SUBDIR.
-    let target_dir_suffix = if args.docker {
-        format!("{}/{}", HELPER_TARGET_SUBDIR, "docker")
+    let mut target_dir_suffix = HELPER_TARGET_SUBDIR.to_string();
+    if args.docker {
+        target_dir_suffix = format!("{}/{}", HELPER_TARGET_SUBDIR, "docker");
+    }
+
+    // The ELF's file name is the binary name if it's specified. Otherwise, it is the root package
+    // name.
+    let original_elf_file_name = if !args.binary.is_empty() {
+        args.binary.clone()
     } else {
-        HELPER_TARGET_SUBDIR.to_string()
+        root_package_name.unwrap().clone()
     };
 
     let original_elf_path = program_metadata
         .target_directory
         .join(target_dir_suffix)
         .join(BUILD_TARGET)
         .join("release")
-        .join(root_package_name.unwrap());
+        .join(original_elf_file_name);
 
     // The order of precedence for the ELF name is:
     // 1. --elf_name flag

helper/src/lib.rs

@@ -61,14 +61,10 @@ fn execute_build_cmd(
     }
 
     // Build the program with the given arguments.
-    let path_output = if let Some(args) = args {
-        sp1_build::build_program(&args, Some(program_dir.as_ref().to_path_buf()))
-    } else {
-        sp1_build::build_program(
-            &BuildArgs::default(),
-            Some(program_dir.as_ref().to_path_buf()),
-        )
-    };
+    let path_output = sp1_build::build_program(
+        &args.unwrap_or_default(),
+        Some(program_dir.as_ref().to_path_buf()),
+    );
     if let Err(err) = path_output {
         panic!("Failed to build SP1 program: {}.", err);
     }