chroma submission: fix crash; better errors

beetsplug/chroma.py

@@ -214,8 +214,10 @@ def submit_items(userkey, items, chunksize=64):
             ))
             try:
                 _, fp = acoustid.fingerprint_file(item.path)
-            except acoustid.FingerprintGenerationError:
-                log.info('fingerprint generation failed')
+            except acoustid.FingerprintGenerationError as exc:
+                log.info(
+                    'fingerprint generation failed: {0}'.format(exc)
+                )
                 continue
 
         # Construct a submission dictionary for this item.
@@ -244,4 +246,5 @@ def submit_items(userkey, items, chunksize=64):
             submit_chunk()
 
     # Submit remaining data in a final chunk.
-    submit_chunk()
+    if data:
+        submit_chunk()

docs/changelog.rst

@@ -20,6 +20,8 @@ Changelog
   after adding files to the library but before finishing copying them; during
   the next import, the (external) files would be moved instead of copied.
 * Fix ID3 tag name for the catalog number field.
+* :doc:`/plugins/chroma`: Fix occasional crash at end of fingerprint submission
+  and give more context to "failed fingerprint generation" errors.
 
 1.0b14 (May 12, 2012)
 ---------------------

docs/plugins/chroma.rst

@@ -29,10 +29,13 @@ To get fingerprinting working, you'll need to install three things: the
 
 First, you will need to install `Chromaprint`_, either as a dynamic library or
 in the form of a command-line tool (``fpcalc``). The Chromaprint site has links
-to packages for major Linux distributions. On Mac OS X and Windows, download the
-appropriate binary package and place the ``fpcalc`` (or ``fpcalc.exe``) on your
-shell search path (e.g., in ``/usr/local/bin`` on Mac OS X or ``C:\\Program
-Files`` on Windows).
+to packages for major Linux distributions. If you use `Homebrew`_ on Mac OS X,
+you can install the library with ``brew install chromaprint``. Otherwise, on Mac
+OS X and Windows, download the appropriate binary package and place the
+``fpcalc`` (or ``fpcalc.exe``) on your shell search path (e.g., in
+``/usr/local/bin`` on Mac OS X or ``C:\\Program Files`` on Windows).
+
+.. _Homebrew: http://mxcl.github.com/homebrew/
 
 Next, you will need a mechanism for decoding audio files supported by the
 `audioread`_ library. Mac OS X has a number of decoders already built into Core