Add trailing whitespace removal and refactor postprocessor

- Add _strip_trailing_whitespace() to remove trailing whitespace
  from all lines except inside fenced code blocks
- Refactor _postprocess_root() to chain helper functions
- Extract _normalize_frontmatter_spacing() from existing code
- Add test_spacing_features.py with tests for trailing whitespace,
  hard breaks, pseudo-heading spacing, and link handling
- Add test_integration.py and test_plugin_interactions.py for
  comprehensive plugin interaction testing
- Add mdformat-simple-breaks and mdformat-wikilink as test deps
- Expand fixtures.md with checkbox list and link test cases

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jdmonaco

mdformat_space_control/plugin.py

@@ -4,6 +4,7 @@
 - EditorConfig-based indentation settings
 - Tight list formatting with multi-paragraph awareness
 - Frontmatter spacing normalization
+- Trailing whitespace removal (outside code blocks)
 """
 
 import re
@@ -186,21 +187,74 @@ def _render_ordered_list(node: RenderTreeNode, context: RenderContext) -> str:
 }
 
 
-def _postprocess_root(text: str, node: RenderTreeNode, context: RenderContext) -> str:
+def _normalize_frontmatter_spacing(text: str) -> str:
     """Normalize spacing after YAML frontmatter.
 
-    Applies two spacing rules:
-    - Heading after frontmatter: no blank line (tight)
-    - Other content after frontmatter: exactly one blank line
+    Removes all blank lines between frontmatter closing delimiter and the
+    first content block, producing tight spacing universally.
+
+    IMPORTANT: Only matches actual frontmatter (document starts with ---)
+    not thematic breaks appearing mid-document.
+    """
+    # Only process if document starts with frontmatter opening delimiter
+    if not text.startswith("---\n"):
+        return text
+
+    # Find the closing delimiter (second --- on its own line)
+    # Pattern: opening --- at start, content, closing --- on its own line
+    frontmatter_match = re.match(r"^---\n.*?\n(---\n)", text, flags=re.DOTALL)
+    if not frontmatter_match:
+        return text
+
+    # Get position after closing delimiter
+    closing_end = frontmatter_match.end(1)
+    before_content = text[:closing_end]
+    after_content = text[closing_end:]
+
+    # Remove all blank lines after frontmatter (tight spacing for any content)
+    after_content = re.sub(r"^\n+", "", after_content)
+
+    return before_content + after_content
+
+
+def _strip_trailing_whitespace(text: str) -> str:
+    """Strip trailing whitespace, preserving code blocks.
+
+    Fenced code blocks (``` or ~~~) preserve trailing whitespace
+    since it may be semantically meaningful in code.
+    """
+    lines = text.split("\n")
+    result = []
+    in_code_block = False
+
+    for line in lines:
+        # Track fenced code block state
+        stripped = line.lstrip()
+        if stripped.startswith("```") or stripped.startswith("~~~"):
+            in_code_block = not in_code_block
+            result.append(line.rstrip())  # Strip fence line itself
+        elif in_code_block:
+            # Preserve trailing whitespace inside code blocks
+            result.append(line)
+        else:
+            # Strip trailing whitespace everywhere else
+            result.append(line.rstrip())
+
+    return "\n".join(result)
+
+
+def _postprocess_root(text: str, node: RenderTreeNode, context: RenderContext) -> str:
+    """Combined postprocessor for all space control features.
 
-    This postprocessor works with mdformat-frontmatter without conflicts
-    since it operates on the rendered output, not the AST.
+    Applies the following transformations in order:
+    1. Frontmatter spacing normalization
+    2. Trailing whitespace removal
     """
-    # Remove blank line(s) before heading: ---\n\n+# → ---\n#
-    text = re.sub(r"^(---\n)\n+(#)", r"\1\2", text, count=1, flags=re.MULTILINE)
+    # 1. Frontmatter spacing
+    text = _normalize_frontmatter_spacing(text)
 
-    # Normalize multiple blank lines to exactly one for non-headings
-    text = re.sub(r"^(---\n)\n{2,}(\S)", r"\1\n\2", text, count=1, flags=re.MULTILINE)
+    # 2. Trailing whitespace removal
+    text = _strip_trailing_whitespace(text)
 
     return text
 

pyproject.toml

@@ -33,6 +33,8 @@ test = [
     "pytest>=7.0",
     "pytest-cov>=4.0",
     "mdformat-frontmatter>=2.0.0",
+    "mdformat-simple-breaks>=0.1.0",
+    "mdformat-wikilink>=0.3.0",
 ]
 
 [project.urls]

tests/fixtures.md

@@ -172,4 +172,83 @@ mixed single and multi paragraph items
   Second paragraph here
 
 - Simple item 2
+.
+
+basic checkbox list
+.
+- [ ] Task 1
+
+- [x] Task 2
+
+- [ ] Task 3
+.
+- [ ] Task 1
+- [x] Task 2
+- [ ] Task 3
+.
+
+nested checkbox list
+.
+- [ ] Parent task 1
+  - [x] Completed subtask
+  - [ ] Pending subtask
+- [x] Parent task 2
+.
+- [ ] Parent task 1
+  - [x] Completed subtask
+  - [ ] Pending subtask
+- [x] Parent task 2
+.
+
+mixed checkbox and regular items
+.
+- [ ] Task item
+
+- Regular item
+
+- [x] Completed task
+.
+- [ ] Task item
+- Regular item
+- [x] Completed task
+.
+
+checkbox with continuation
+.
+- [ ] Task with
+  continuation text
+- [x] Another task
+.
+- [ ] Task with
+  continuation text
+- [x] Another task
+.
+
+multi-paragraph checkbox item
+.
+- [ ] Task with paragraphs
+
+  Second paragraph here.
+
+- [x] Simple task
+.
+- [ ] Task with paragraphs
+
+  Second paragraph here.
+
+- [x] Simple task
+.
+
+normal link unchanged
+.
+[normal link](https://example.com)
+.
+[normal link](https://example.com)
+.
+
+link in paragraph
+.
+Check [this link](https://example.com) for info.
+.
+Check [this link](https://example.com) for info.
 .

tests/test_editorconfig.py

@@ -484,3 +484,57 @@ def test_nested_with_multi_paragraph(self, temp_project):
 """
         result = format_with_context(input_text, md_file)
         assert result == expected
+
+
+class TestEditorConfigDebug:
+    """Tests documenting EditorConfig resolution behavior."""
+
+    def test_cwd_differs_from_file_location(self, temp_project, monkeypatch):
+        """When CWD differs from file location, explicit file context wins."""
+        create_editorconfig(
+            temp_project,
+            """
+root = true
+
+[*.md]
+indent_style = space
+indent_size = 4
+""",
+        )
+
+        other_dir = temp_project / "other"
+        other_dir.mkdir()
+        monkeypatch.chdir(other_dir)
+
+        md_file = temp_project / "doc.md"
+        result = format_with_context("- A\n  - B\n", md_file)
+        assert "    - B" in result  # 4-space indent
+
+    def test_obsidian_scenario_no_file_context(self, temp_project, monkeypatch):
+        """Document behavior when no file context is set (Obsidian-like)."""
+        vault = temp_project / "vault"
+        vault.mkdir()
+        create_editorconfig(
+            vault,
+            """
+root = true
+
+[*.md]
+indent_style = space
+indent_size = 4
+""",
+        )
+
+        app_dir = temp_project / "app"
+        app_dir.mkdir()
+        monkeypatch.chdir(app_dir)
+
+        fake_home = temp_project / "fake_home"
+        fake_home.mkdir()
+        monkeypatch.setattr(Path, "home", lambda: fake_home)
+
+        set_current_file(None)
+
+        # Without file context, vault's .editorconfig is NOT found
+        result = mdformat.text("- A\n  - B\n", extensions={"space_control"})
+        assert "  - B" in result  # 2-space default