Adjustable whitelines feature

docs/index.md

@@ -194,6 +194,23 @@ export YAMLFIX_COMMENTS_REQUIRE_STARTING_SPACE="true"
 
 This option enforces a space between the comment indicator (`#`) and the first character in the comment. It implements the enforcement of the yamllint rule `rules.comments.require-starting-space` - see: https://yamllint.readthedocs.io/en/stable/rules.html#module-yamllint.rules.comments
 
+### Whitelines Adjusting
+
+Default: `whitelines: int = 0`<br>
+Environment variable override:
+```bash
+export YAMLFIX_WHITELINES="0"
+```
+
+This option allows to keep a speficied number of whitelines between lines. 
+
+It's useful if, for one, you like to separate GitHub Actions job steps or Docker-Compose 
+service definitions with a blank line.
+
+Bear in mind that, like **Comments Whitelines**, it won't insert whitelines if there's no 
+whitelines in the first place. It will only fix 1 or more whitelines to the desired 
+amount (or remove them completely by default).
+
 ### Comments Whitelines
 
 Default: `comments_whitelines: int = 1`<br>

src/yamlfix/adapters.py

@@ -353,9 +353,9 @@ def fix(self, source_code: str) -> str:
             self._restore_jinja_variables,
             self._restore_double_exclamations,
             self._fix_comments,
+            self._fix_flow_style_lists,
             self._fix_whitelines,
             self._fix_top_level_lists,
-            self._fix_flow_style_lists,
             self._add_newline_at_end_of_file,
         ]
 
@@ -478,7 +478,7 @@ def _fix_flow_style_lists(source_code: str) -> str:
         ```
 
         This function moves the closing bracket to the end of the flow-style
-        list definition.
+        list definition and positions the newlines after the closing bracket.
 
         Args:
             source_code: Source code to be corrected.
@@ -487,26 +487,9 @@ def _fix_flow_style_lists(source_code: str) -> str:
             Corrected source code.
         """
         log.debug("Fixing flow-style lists...")
-        source_lines = source_code.splitlines()
-        reversed_fixed_source_lines: List[str] = []
-
-        should_append_square_brackets: bool = False
-        for line in reversed(source_lines):
-            if line == "]":
-                should_append_square_brackets = True
-                continue
-
-            if line == "":
-                reversed_fixed_source_lines.append(line)
-                continue
-
-            if should_append_square_brackets:
-                should_append_square_brackets = False
-                reversed_fixed_source_lines.append(line + "]")
-            else:
-                reversed_fixed_source_lines.append(line)
-
-        return "\n".join(reversed(reversed_fixed_source_lines))
+        pattern = r"\[(?P<items>.*)(?P<newlines>\n+)]"
+        replacement = r"[\g<items>]\g<newlines>"
+        return re.sub(pattern, repl=replacement, string=source_code)
 
     @staticmethod
     def _fix_truthy_strings(source_code: str) -> str:
@@ -616,8 +599,8 @@ def _fix_whitelines(self, source_code: str) -> str:
           - 0 whiteline is allowed
           - Exactly `self.config.comments_whitelines` whitelines are allowed
 
-        This method removes extraneous whitelines that are not immediately followed by
-        a comment.
+        This method also adjusts amount of whitelines that are not immediately followed
+        by a comment.
 
         Args:
             self: Source code to be corrected.
@@ -626,20 +609,21 @@ def _fix_whitelines(self, source_code: str) -> str:
             Source code with appropriate whitelines standards.
         """
         config = self.config
+        n_whitelines = config.whitelines
         n_whitelines_from_content = config.comments_whitelines
 
         re_whitelines_with_comments = "\n\n+[\t ]{0,}[#]"
         re_whitelines_with_no_comments = "\n\n+[\t ]{0,}[^#\n\t ]"
 
-        remove_whitelines = partial(self._replace_whitelines, n_whitelines=0)
+        adjust_whitelines = partial(self._replace_whitelines, n_whitelines=n_whitelines)
         replace_by_n_whitelines = partial(
             self._replace_whitelines,
             n_whitelines=n_whitelines_from_content,
         )
 
         source_code = re.sub(
             pattern=re_whitelines_with_no_comments,
-            repl=remove_whitelines,
+            repl=adjust_whitelines,
             string=source_code,
         )
         source_code = self._fix_section_whitelines(source_code)
@@ -722,7 +706,15 @@ def _restore_double_exclamations(source_code: str) -> str:
 
     @staticmethod
     def _add_newline_at_end_of_file(source_code: str) -> str:
-        return source_code + "\n"
+        """Ensures that the file ends with exactly one newline.
+
+        Args:
+            source_code: Source code to be corrected.
+
+        Returns:
+            Corrected source code.
+        """
+        return source_code.rstrip() + "\n"
 
     @staticmethod
     def _fix_jinja_variables(source_code: str) -> str:

src/yamlfix/model.py

@@ -20,6 +20,7 @@ class YamlfixConfig(ConfigSchema):
     comments_min_spaces_from_content: int = 2
     comments_require_starting_space: bool = True
     comments_whitelines: int = 1
+    whitelines: int = 0
     section_whitelines: int = 0
     config_path: Optional[str] = None
     explicit_start: bool = True

tests/unit/test_adapter_yaml.py

@@ -830,3 +830,112 @@ def test_section_whitelines_begin_no_explicit_start(self) -> None:
         result = fix_code(source, config)
 
         assert result == fixed_source
+
+    def test_whitelines_collapsed(self) -> None:
+        """Checks that whitelines are collapsed by default."""
+        source = dedent(
+            """\
+            key: value
+
+            dict:
+              key: value
+              nested_dict:
+                - key: value
+                  key2: value2
+
+                - key: value
+            """
+        )
+        fixed_source = dedent(
+            """\
+            ---
+            key: value
+            dict:
+              key: value
+              nested_dict:
+                - key: value
+                  key2: value2
+                - key: value
+            """
+        )
+        config = YamlfixConfig()
+
+        result = fix_code(source, config)
+
+        assert result == fixed_source
+
+    def test_whitelines_adjusted_to_value(self) -> None:
+        """Checks that amount of whitelines are in line with the config value."""
+        source = dedent(
+            """\
+            key: value
+
+            dict:
+              key: value
+
+
+              nested_list:
+                - key: value
+                  key2: value2
+
+                - key: value
+            """
+        )
+        fixed_source = dedent(
+            """\
+            ---
+            key: value
+            dict:
+              key: value
+
+              nested_list:
+                - key: value
+                  key2: value2
+
+                - key: value
+            """
+        )
+        config = YamlfixConfig()
+        config.whitelines = 1
+
+        result = fix_code(source, config)
+
+        assert result == fixed_source
+
+    def test_enforcing_flow_style_together_with_adjustable_newlines(self) -> None:
+        """Checks that transforming block style sequences to flow style together with
+        newlines adjusting produces correct result.
+        """
+        source = dedent(
+            """\
+            ---
+            dict:
+              nested_dict:
+                key: value
+                key2:
+                  - list_item
+
+
+              nested_dict2:
+                key: value
+            """
+        )
+        fixed_source = dedent(
+            """\
+            ---
+            dict:
+              nested_dict:
+                key: value
+                key2: [list_item]
+
+              nested_dict2:
+                key: value
+            """
+        )
+        config = YamlfixConfig()
+        config.whitelines = 1
+        config.sequence_style = YamlNodeStyle.FLOW_STYLE
+
+        result = fix_code(source, config)
+
+        assert result == fixed_source

tests/unit/test_services.py

@@ -469,7 +469,7 @@ def test_fix_code_functions_emit_debug_logs(
 
         fix_code("")  # act
 
-        expected_logs = [
+        expected_logs = {
             "Setting up ruamel yaml 'quote simple values' configuration...",
             "Setting up ruamel yaml 'sequence flow style' configuration...",
             "Running ruamel yaml base configuration...",
@@ -483,8 +483,8 @@ def test_fix_code_functions_emit_debug_logs(
             "Fixing comments...",
             "Fixing top level lists...",
             "Fixing flow-style lists...",
-        ]
-        assert caplog.messages == expected_logs
+        }
+        assert set(caplog.messages) == expected_logs
         for record in caplog.records:
             assert record.levelname == "DEBUG"