fix ChunkerParams validator and tests

(cherry picked from commit 6d38530ff10eb77c02594d00b484fab26c6520dd)

src/borg/helpers/parseformat.py

@@ -98,7 +98,7 @@ def ChunkerParams(s):
     params = s.strip().split(',')
     count = len(params)
     if count == 0:
-        raise ValueError('no chunker params given')
+        raise argparse.ArgumentTypeError('no chunker params given')
     algo = params[0].lower()
     if algo == CH_FIXED and 2 <= count <= 3:  # fixed, block_size[, header_size]
         block_size = int(params[1])
@@ -109,9 +109,11 @@ def ChunkerParams(s):
             # or in-memory chunk management.
             # choose the block (chunk) size wisely: if you have a lot of data and you cut
             # it into very small chunks, you are asking for trouble!
-            raise ValueError('block_size must not be less than 64 Bytes')
+            raise argparse.ArgumentTypeError('block_size must not be less than 64 Bytes')
         if block_size > MAX_DATA_SIZE or header_size > MAX_DATA_SIZE:
-            raise ValueError('block_size and header_size must not exceed MAX_DATA_SIZE [%d]' % MAX_DATA_SIZE)
+            raise argparse.ArgumentTypeError(
+                'block_size and header_size must not exceed MAX_DATA_SIZE [%d]' % MAX_DATA_SIZE
+            )
         return algo, block_size, header_size
     if algo == 'default' and count == 1:  # default
         return CHUNKER_PARAMS
@@ -119,14 +121,18 @@ def ChunkerParams(s):
     if algo == CH_BUZHASH and count == 5 or count == 4:  # [buzhash, ]chunk_min, chunk_max, chunk_mask, window_size
         chunk_min, chunk_max, chunk_mask, window_size = (int(p) for p in params[count - 4:])
         if not (chunk_min <= chunk_mask <= chunk_max):
-            raise ValueError('required: chunk_min <= chunk_mask <= chunk_max')
+            raise argparse.ArgumentTypeError('required: chunk_min <= chunk_mask <= chunk_max')
         if chunk_min < 6:
             # see comment in 'fixed' algo check
-            raise ValueError('min. chunk size exponent must not be less than 6 (2^6 = 64B min. chunk size)')
+            raise argparse.ArgumentTypeError(
+                'min. chunk size exponent must not be less than 6 (2^6 = 64B min. chunk size)'
+            )
         if chunk_max > 23:
-            raise ValueError('max. chunk size exponent must not be more than 23 (2^23 = 8MiB max. chunk size)')
+            raise argparse.ArgumentTypeError(
+                'max. chunk size exponent must not be more than 23 (2^23 = 8MiB max. chunk size)'
+            )
         return CH_BUZHASH, chunk_min, chunk_max, chunk_mask, window_size
-    raise ValueError('invalid chunker params')
+    raise argparse.ArgumentTypeError('invalid chunker params')
 
 
 def FilesCacheMode(s):

src/borg/testsuite/helpers.py

@@ -348,19 +348,19 @@ def test_chunkerparams():
     assert ChunkerParams('fixed,4096') == ('fixed', 4096, 0)
     assert ChunkerParams('fixed,4096,200') == ('fixed', 4096, 200)
     # invalid values checking
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('crap,1,2,3,4')  # invalid algo
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('buzhash,5,7,6,4095')  # too small min. size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('buzhash,19,24,21,4095')  # too big max. size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('buzhash,23,19,21,4095')  # violates min <= mask <= max
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('fixed,63')  # too small block size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('fixed,%d,%d' % (MAX_DATA_SIZE + 1, 4096))  # too big block size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams('fixed,%d,%d' % (4096, MAX_DATA_SIZE + 1))  # too big header size