Merge pull request #2412 from midichef/guess_errors

[loaders-] handle exceptions in filetype guess

visidata/loaders/csv.py

@@ -16,7 +16,10 @@
 def guess_csv(vd, p):
     import csv
     csv.field_size_limit(2**31-1)  #288 Windows has max 32-bit
-    line = next(p.open())
+    try:
+        line = next(p.open())
+    except StopIteration:
+        return
     if ',' in line:
         dialect = csv.Sniffer().sniff(line)
         r = dict(filetype='csv', _likelihood=0)

visidata/loaders/json.py

@@ -11,7 +11,10 @@
 @VisiData.api
 def guess_json(vd, p):
     with p.open(encoding=vd.options.encoding) as fp:
-        line = next(fp)
+        try:
+            line = next(fp)
+        except StopIteration:
+            return
 
     line = line.strip()
 

visidata/loaders/jsonla.py

@@ -18,10 +18,16 @@ def guess_jsonla(vd, p):
     '''
 
     with p.open(encoding=vd.options.encoding) as fp:
-        first_line = next(fp)
+        try:
+            first_line = next(fp)
+        except StopIteration:
+            return
 
     if first_line.strip().startswith('['):
-        ret = json.loads(first_line)
+        try:
+            ret = json.loads(first_line)
+        except json.decoder.JSONDecodeError:
+            return
         if isinstance(ret, list) and all(isinstance(v, str) for v in ret):
             return dict(filetype='jsonla')