Fix file encoding support bom, latin1, Windows files

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,57 +1,33 @@
 name: Bug Report
 description: Report a bug or unexpected behavior
-title: "[Bug]: "
 labels: ["bug"]
 body:
-  - type: markdown
-    attributes:
-      value: |
-        Thanks for reporting an issue! Please fill out the sections below.
-
   - type: textarea
     id: description
     attributes:
       label: Description
-      description: A clear description of what the bug is.
-      placeholder: Tell us what happened
+      description: What happened?
+      placeholder: Describe the issue
     validations:
       required: true
 
   - type: textarea
     id: reproduction
     attributes:
       label: Steps to Reproduce
-      description: Steps to reproduce the behavior
       placeholder: |
         1. Load diff with `load_diff("path/to/file.diff")`
         2. Run `list_chunks()`
         3. See error
-    validations:
-      required: true
-
-  - type: textarea
-    id: expected
-    attributes:
-      label: Expected Behavior
-      description: What you expected to happen
-    validations:
-      required: true
 
   - type: textarea
     id: environment
     attributes:
       label: Environment
-      description: Your environment details
-      value: |
-        - OS: [e.g., Windows 11, macOS 14, Ubuntu 22.04]
-        - Python version: [e.g., 3.10.12]
-        - diffchunk version: [e.g., 0.1.0]
-        - MCP client: [e.g., Claude Desktop]
-    validations:
-      required: true
+      placeholder: OS, Python version, diffchunk version, etc.
 
   - type: textarea
     id: additional
     attributes:
       label: Additional Context
-      description: Any other context, screenshots, or files related to the problem
+      description: Screenshots, logs, or other relevant information

.gitignore

@@ -75,3 +75,6 @@ Thumbs.db
 *.patch
 !tests/test_data/*.diff
 test_output/
+
+# example repos folders for diffs
+repos/

src/parser.py

@@ -19,11 +19,7 @@ def __init__(self):
 
     def parse_diff_file(self, file_path: str) -> Iterator[Tuple[List[str], str]]:
         """Parse a diff file and yield (files, content) tuples."""
-        try:
-            with open(file_path, "r", encoding="utf-8", errors="replace") as f:
-                lines = f.readlines()
-        except (IOError, OSError) as e:
-            raise ValueError(f"Cannot read diff file {file_path}: {e}")
+        lines = self._read_diff_file(file_path)
 
         if not lines:
             return
@@ -126,6 +122,31 @@ def should_include_file(
 
         return True  # Include by default if no patterns specified
 
+    def _read_diff_file(self, file_path: str) -> List[str]:
+        """Read diff file with proper encoding handling."""
+        # Try UTF-8 first (most common)
+        encodings = ["utf-8", "utf-8-sig", "cp1252", "latin-1"]
+
+        for encoding in encodings:
+            try:
+                with open(file_path, "r", encoding=encoding) as f:
+                    content = f.read()
+
+                # Strip BOM if present
+                if content.startswith("\ufeff"):
+                    content = content[1:]
+
+                lines = content.splitlines(keepends=True)
+                return lines
+
+            except (UnicodeDecodeError, IOError):
+                continue
+
+        # If all encodings failed, raise clear error
+        raise ValueError(
+            f"Cannot read diff file {file_path}: unable to decode with any common encoding"
+        )
+
     def count_lines(self, content: str) -> int:
         """Count meaningful lines in diff content."""
         return len([line for line in content.split("\n") if line.strip()])

tests/test_data/minimal_bom.diff

@@ -0,0 +1,8 @@
+diff --git a/file1.txt b/file1.txt
+index 1234567..abcdefg 100644
+--- a/file1.txt
++++ b/file1.txt
+@@ -1,2 +1,2 @@
+ line 1
+-old line
++new line

tests/test_data/minimal_latin1.diff

@@ -0,0 +1,8 @@
+diff --git a/fil�.txt b/fil�.txt
+index 1234567..abcdefg 100644
+--- a/fil�.txt
++++ b/fil�.txt
+@@ -1,2 +1,2 @@
+ line 1
+-old lin�
++new lin�

tests/test_data/minimal_windows.diff

@@ -0,0 +1,8 @@
+diff --git a/file1.txt b/file1.txt
+index 1234567..abcdefg 100644
+--- a/file1.txt
++++ b/file1.txt
+@@ -1,2 +1,2 @@
+ line 1
+-old line
++new line

tests/test_data/minimal_working.diff

@@ -0,0 +1,8 @@
+diff --git a/file1.txt b/file1.txt
+index 1234567..abcdefg 100644
+--- a/file1.txt
++++ b/file1.txt
+@@ -1,2 +1,2 @@
+ line 1
+-old line
++new line

tests/test_windows_repro.py

@@ -0,0 +1,34 @@
+"""Test to reproduce Windows "No valid diff content found" issue."""
+
+import pytest
+from pathlib import Path
+
+from src.tools import DiffChunkTools
+
+
+class TestWindowsEncoding:
+    """Test Windows encoding issues that cause 'No valid diff content found'."""
+
+    @pytest.fixture
+    def test_data_dir(self):
+        return Path(__file__).parent / "test_data"
+
+    @pytest.fixture
+    def tools(self):
+        return DiffChunkTools()
+
+    def test_encoding_scenarios_work_with_fix(self, tools, test_data_dir):
+        """Test that encoding scenarios work with the fix."""
+        working_files = [
+            "minimal_working.diff",  # UTF-8 baseline
+            "minimal_windows.diff",  # Windows \r\n line endings
+            "minimal_bom.diff",  # UTF-8 BOM (now handled)
+            "minimal_latin1.diff",  # Latin-1 encoding (now handled)
+        ]
+
+        for filename in working_files:
+            result = tools.load_diff(
+                str(test_data_dir / filename), max_chunk_lines=1000
+            )
+            assert result["chunks"] > 0, f"{filename} should work with fix"
+            assert result["files"] > 0, f"{filename} should have files"