Add preserve_block_seqs_indents

_test/test_block_seq_local_indent.py

@@ -0,0 +1,97 @@
+
+import pytest
+import io
+import ruyaml  # NOQA
+from .roundtrip import round_trip, dedent
+
+from ruyaml import YAML
+from ruyaml.util import load_yaml_guess_indent
+from ruyaml.scalarbool import ScalarBoolean
+from ruyaml.comments import CommentedSeq
+from ruyaml.representer import RoundTripRepresenter, ScalarNode
+from ruyaml.constructor import RoundTripConstructor
+from typing import Text, Any, Dict, List  # NOQA
+
+
+def round_trip_stabler(
+    inp,
+    outp=None,
+):
+    if outp is None:
+        outp = inp
+    doutp = dedent(outp)
+    yaml = ruyaml.YAML()
+    yaml.preserve_quotes = True
+    yaml.preserve_block_seqs_indents = True
+    data = yaml.load(doutp)
+    buf = io.StringIO()
+    yaml.dump(data, stream=buf)
+    res = buf.getvalue()
+    assert res == doutp
+
+
+class TestStability:
+
+    def test_blockseq1(self):
+        round_trip(
+            """
+        a:
+        - a1
+        - a2
+        """
+        )
+
+    @pytest.mark.xfail(strict=True)
+    def test_blockseq2(self):
+        round_trip(
+            """
+        a:
+          - a1
+          - a2
+        """
+        )
+
+    @pytest.mark.xfail(strict=True)
+    def test_blockseq3(self):
+        round_trip(
+            """
+        a:
+          - a1
+          - a2
+        b:
+        - b1
+        - b2
+        """
+        )
+
+class TestStabilityStabler:
+
+    def test_blockseq1(self):
+        round_trip_stabler(
+            """
+        a:
+        - a1
+        - a2
+        """
+        )
+
+    def test_blockseq2(self):
+        round_trip_stabler(
+            """
+        a:
+          - a1
+          - a2
+        """
+        )
+
+    def test_blockseq3(self):
+        round_trip_stabler(
+            """
+        a:
+          - a1
+          - a2
+        b:
+        - b1
+        - b2
+        """
+        )

lib/ruyaml/emitter.py

@@ -117,6 +117,7 @@ def __init__(
         top_level_colon_align=None,
         prefix_colon=None,
         brace_single_entry_mapping_in_flow_sequence=None,
+        preserve_block_seqs_indents=None,
         dumper=None,
     ):
         # type: (StreamType, Any, Optional[int], Optional[int], Optional[bool], Any, Optional[int], Optional[bool], Any, Optional[bool], Any) -> None  # NOQA
@@ -185,6 +186,8 @@ def __init__(
         # set to False to get "\Uxxxxxxxx" for non-basic unicode like emojis
         self.unicode_supplementary = sys.maxunicode > 0xFFFF
         self.sequence_dash_offset = block_seq_indent if block_seq_indent else 0
+        self.preserve_block_seqs_indents = preserve_block_seqs_indents
+        self.current_local_block_seq_indent = None
         self.top_level_colon_align = top_level_colon_align
         self.best_sequence_indent = 2
         self.requested_indent = indent  # specific for literal zero indent
@@ -446,6 +449,7 @@ def expect_node(self, root=False, sequence=False, mapping=False, simple_key=Fals
                 self.expect_scalar()
             elif isinstance(self.event, SequenceStartEvent):
                 # nprint('@', self.indention, self.no_newline, self.column)
+                self.current_local_block_seq_indent = self.event.block_seq_indent
                 i2, n2 = self.indention, self.no_newline  # NOQA
                 if self.event.comment:
                     if self.event.flow_style is False and self.event.comment:
@@ -669,9 +673,12 @@ def expect_block_sequence_item(self, first=False):
                 self.write_pre_comment(self.event)
             nonl = self.no_newline if self.column == 0 else False
             self.write_indent()
-            ind = self.sequence_dash_offset  # if  len(self.indents) > 1 else 0
+            cur_dash_offset = self.sequence_dash_offset
+            if self.current_local_block_seq_indent and self.preserve_block_seqs_indents:
+                cur_dash_offset = self.current_local_block_seq_indent
+            ind = cur_dash_offset  # if  len(self.indents) > 1 else 0
             self.write_indicator(' ' * ind + '-', True, indention=True)
-            if nonl or self.sequence_dash_offset + 2 > self.best_sequence_indent:
+            if nonl or cur_dash_offset + 2 > self.best_sequence_indent:
                 self.no_newline = True
             self.states.append(self.expect_block_sequence_item)
             self.expect_node(sequence=True)

lib/ruyaml/events.py

@@ -186,7 +186,23 @@ def __init__(
 
 
 class SequenceStartEvent(CollectionStartEvent):
-    __slots__ = ()
+    __slots__ = ('block_seq_indent', )
+
+    def __init__(
+        self,
+        anchor,
+        tag,
+        implicit,
+        start_mark=None,
+        end_mark=None,
+        flow_style=None,
+        comment=None,
+        nr_items=None,
+        block_seq_indent=None,
+    ):
+        # type: (Any, Any, Any, Any, Any, Any, Any, Optional[int]) -> None
+        CollectionStartEvent.__init__(self, anchor, tag, implicit, start_mark, end_mark, flow_style, comment, nr_items)
+        self.block_seq_indent = block_seq_indent
 
 
 class SequenceEndEvent(CollectionEndEvent):

lib/ruyaml/main.py

@@ -169,6 +169,7 @@ def __init__(
         self.version = None
         self.preserve_quotes = None
         self.preserve_bools = None
+        self.preserve_block_seqs_indents = None
         self.allow_duplicate_keys = False  # duplicate keys in map, set
         self.encoding = 'utf-8'
         self.explicit_start = None
@@ -273,6 +274,7 @@ def emitter(self):
                     line_break=self.line_break,
                     prefix_colon=self.prefix_colon,
                     brace_single_entry_mapping_in_flow_sequence=self.brace_single_entry_mapping_in_flow_sequence,  # NOQA
+                    preserve_block_seqs_indents=self.preserve_block_seqs_indents,
                     dumper=self,
                 )
                 setattr(self, attr, _emitter)

lib/ruyaml/nodes.py

@@ -121,9 +121,25 @@ def __init__(
 
 
 class SequenceNode(CollectionNode):
-    __slots__ = ()
+    __slots__ = ('block_seq_indent', )
     id = 'sequence'
 
+    def __init__(
+        self,
+        tag,
+        value,
+        start_mark=None,
+        end_mark=None,
+        flow_style=None,
+        comment=None,
+        anchor=None,
+    ):
+        # type: (Any, Any, Any, Any, Any, Any, Any) -> None
+        CollectionNode.__init__(
+            self, tag, value, start_mark, end_mark, flow_style, comment, anchor
+        )
+        self.block_seq_indent = None
+
 
 class MappingNode(CollectionNode):
     __slots__ = ('merge',)

lib/ruyaml/representer.py

@@ -815,8 +815,19 @@ def represent_sequence(self, tag, sequence, flow_style=None):
                 node.flow_style = self.default_flow_style
             else:
                 node.flow_style = best_style
+        self.set_block_seq_indent(node, sequence)
         return node
 
+    def set_block_seq_indent(self, node, sequence):
+        local_block_seq_indent = 10000
+        if not isinstance(sequence, CommentedSeq):
+            return
+        if not sequence.lc.data:
+            return
+        for lc_item in sequence.lc.data.values():
+            local_block_seq_indent = min(local_block_seq_indent, lc_item[1] - 2)  # Why '2'?
+        node.block_seq_indent = local_block_seq_indent
+
     def merge_comments(self, node, comments):
         # type: (Any, Any) -> Any
         if comments is None:

lib/ruyaml/serializer.py

@@ -208,6 +208,7 @@ def serialize_node(self, node, parent, index):
                         implicit,
                         flow_style=node.flow_style,
                         comment=node.comment,
+                        block_seq_indent=node.block_seq_indent,
                     )
                 )
                 index = 0