Fix worker-pool crash on tokens with whitespace surface forms

A token whose FORM is whitespace (e.g. a lone space) collapsed the
tab-separated CoNLL-U line under str.split(), leaving 9 fields instead
of 10 and raising IndexError on the score column in CoNLLUP_Token. The
exception was uncaught and killed the whole streaming process, so
korapxmltool's worker pool saw a broken pipe, re-queued the in-flight
documents, and re-crashed on the same poisoned input until every worker
died -- observed as running threads dropping off one-by-one after tens
of thousands of texts.

CoNLLUP_Token now parses on the tab delimiter (preserving whitespace
FORM columns), falls back to whitespace splitting for space-delimited
input, and pads short lines to the 10 CoNLL-U columns. As
defense-in-depth, a parse/annotation failure for a single document is
now logged and skipped while still echoing its # eot/# eof marker, so
one bad document can no longer take down the run.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Change-Id: I99b96a1ce21e23c1ebb3775afec4c3014d4e9253
diff --git a/lib/CoNLL_Annotation.py b/lib/CoNLL_Annotation.py
index 1a8ddf0..06ea564 100644
--- a/lib/CoNLL_Annotation.py
+++ b/lib/CoNLL_Annotation.py
@@ -73,7 +73,20 @@
 
 class CoNLLUP_Token():
     def __init__(self, raw_line, word_ix):
-        info = raw_line.split()
+        # CoNLL-U is tab-separated with 10 columns. Split on the tab so that a
+        # token whose FORM is whitespace (e.g. a surface form that is a single
+        # space) keeps its column position instead of collapsing it -- a bare
+        # raw_line.split() would drop the empty FORM field, shift every column
+        # left, and raise IndexError on info[9], which crashes the whole
+        # streaming process and cascades into broken pipes across the worker
+        # pool. Fall back to a generic whitespace split for space-delimited
+        # inputs, then pad to 10 columns so a genuinely malformed/short line
+        # degrades gracefully rather than killing the stream.
+        info = raw_line.rstrip("\n").split("\t")
+        if len(info) < 10:
+            info = raw_line.split()
+        if len(info) < 10:
+            info = info + ["_"] * (10 - len(info))
         # print(info)
         # [ID, FORM, LEMMA, UPOS, XPOS, FEATS, HEAD, DEPREL, DEPS, MISC]
         # [11, Prügel, Prügel, NN, NN, _, _, _,	_, 1.000000]