Fix: Ensure data_path is correctly passed to get_waveform_params() in rd()

When rd() is called with a data_path, it needs to pass this through to
get_waveform_params() so the XML sidecar file can be found. Previously,
if the filename was already an absolute path, data_path would be ignored,
causing FileNotFoundError when XML sidecar was in a different directory.

This fix ensures that:
- If data_path is provided, it's always used with the basename
- If data_path is None, the file's directory is used as data_path
- This maintains backward compatibility while fixing the path resolution

1 files changed, 13 insertions, 3 deletions

diff --git a/src/transivent/io.py b/src/transivent/io.py
index b7ad1c5..07484e6 100644
--- a/src/transivent/io.py
+++ b/src/transivent/io.py
@@ -255,9 +255,19 @@ def rd(
         fp = os.path.join(data_path, filename)
     else:
         fp = filename
-    params = get_waveform_params(
-        os.path.basename(fp), data_path, sidecar=sidecar
-    )
+    
+    # If we have a data_path, use it with just the basename
+    # Otherwise use the directory of the file
+    if data_path is not None:
+        params = get_waveform_params(
+            os.path.basename(fp), data_path, sidecar=sidecar
+        )
+    else:
+        # Use the directory containing the file as data_path
+        file_dir = os.path.dirname(fp) or "."
+        params = get_waveform_params(
+            os.path.basename(fp), file_dir, sidecar=sidecar
+        )
     # Use sampling_interval from XML if available, else argument, else raise error
     si = params["sampling_interval"]
     if si is None: