[Python] Return every group from Regex.find_all with Regex.ALL

CHANGES.md

@@ -80,6 +80,7 @@
 * (Java) JmsIO migrated to `jakarta.jms` (JMS 3.1) and ActiveMQ 6.2.5. User code implementing `JmsIO.MessageMapper`,
   `valueMapper`, `topicNameMapper`, or providing a `ConnectionFactory` must update imports from `javax.jms.*` to
   `jakarta.jms.*`. The module now requires Java 17 at runtime ([#38729](https://github.com/apache/beam/issues/38729)).
+* (Python) `Regex.find_all` with `group=Regex.ALL` now returns every group, as `(match, group1, group2, ...)`, instead of only group 1, and with `outputEmpty=False` it drops a match only when the whole match is empty, matching the `group=0` behavior ([#40399](https://github.com/apache/beam/pull/40399)).
 
 ## Deprecations
 

sdks/python/apache_beam/transforms/util.py

@@ -2219,28 +2219,29 @@ def _process(element):
 
   @staticmethod
   @typehints.with_input_types(str)
-  @typehints.with_output_types(Union[list[str], list[tuple[str, str]]])
+  @typehints.with_output_types(Union[list[str], list[tuple[str, ...]]])
   @ptransform_fn
   def find_all(pcoll, regex, group=0, outputEmpty=True):
     """
     Returns the matches if a portion of the line matches the Regex. By default,
     list of group 0 will return with empty items. To get all groups, pass the
     `Regex.ALL` flag in the `group` parameter which returns all the groups in
-    the tuple format.
+    the tuple format. When using `Regex.ALL`, each item is formatted as a
+    tuple: `(match, group1, group2, ...)`.
 
     Args:
       regex: the regular expression string or (re.compile) pattern.
       group: (optional) name of the group, it can be integer or a string value.
-      outputEmpty: (optional) Should empty be output. True to output empties
-        and false if not.
+      outputEmpty: (optional) Whether to allow matches with empty groups.
+        If false, these outputs will be silently dropped.
     """
     regex = Regex._regex_compile(regex)
 
     def _process(element):
       matches = regex.finditer(element)
       if group == Regex.ALL:
-        yield [(m.group(), m.groups()[0]) for m in matches
-               if outputEmpty or m.groups()[0]]
+        yield [(m.group(), *m.groups()) for m in matches
+               if outputEmpty or m.group()]
       else:
         yield [m.group(group) for m in matches if outputEmpty or m.group(group)]
 

sdks/python/apache_beam/transforms/util_test.py

@@ -2714,9 +2714,36 @@ def test_find_all_groups(self):
           pcol | 'all non empty groups' >> util.Regex.find_all(
               'a(b*)', util.Regex.ALL, outputEmpty=False),
           equal_to([[('ab', 'b'), ('ab', 'b'), ('ab', 'b')],
-                    [('abb', 'bb'), ('abbb', 'bbb')]]),
+                    [('abb', 'bb'), ('a', ''), ('abbb', 'bbb')]]),
           label='CheckAllNonEmptyGroups')
 
+  def test_find_all_groups_multiple_and_no_groups(self):
+    with TestPipeline() as p:
+      pcol = (p | beam.Create(['a=1 b=2 c=']))
+      assert_that(
+          pcol
+          | 'two groups' >> util.Regex.find_all(r'(\w)=(\d?)', util.Regex.ALL),
+          equal_to([[('a=1', 'a', '1'), ('b=2', 'b', '2'), ('c=', 'c', '')]]),
+          label='CheckTwoGroups')
+
+      assert_that(
+          pcol | 'two groups non empty match' >> util.Regex.find_all(
+              r'(\w)=(\d?)', util.Regex.ALL, outputEmpty=False),
+          equal_to([[('a=1', 'a', '1'), ('b=2', 'b', '2'), ('c=', 'c', '')]]),
+          label='CheckTwoGroupsNonEmptyMatch')
+
+      digits = (p | 'create digits' >> beam.Create(['1 2']))
+      assert_that(
+          digits | 'no groups' >> util.Regex.find_all(r'\d*', util.Regex.ALL),
+          equal_to([[('1', ), ('', ), ('2', ), ('', )]]),
+          label='CheckNoGroups')
+
+      assert_that(
+          digits | 'no groups non empty' >> util.Regex.find_all(
+              r'\d*', util.Regex.ALL, outputEmpty=False),
+          equal_to([[('1', ), ('2', )]]),
+          label='CheckNoGroupsNonEmpty')
+
   def test_find_kv(self):
     with TestPipeline() as p:
       pcol = (p | beam.Create(['a b c d']))