1 files changed, 226 insertions, 0 deletions
diff --git a/test/lib/ansible_test/_internal/diff.py b/test/lib/ansible_test/_internal/diff.py
new file mode 100644
index 0000000..edaf6c5
--- /dev/null
+++ b/test/lib/ansible_test/_internal/diff.py
@@ -0,0 +1,226 @@
+"""Diff parsing functions and classes."""
+from __future__ import annotations
+
+import re
+import textwrap
+import traceback
+import typing as t
+
+from .util import (
+    ApplicationError,
+)
+
+
+def parse_diff(lines: list[str]) -> list[FileDiff]:
+    """Parse the given diff lines and return a list of FileDiff objects representing the changes of each file."""
+    return DiffParser(lines).files
+
+
+class FileDiff:
+    """Parsed diff for a single file."""
+    def __init__(self, old_path: str, new_path: str) -> None:
+        self.old = DiffSide(old_path, new=False)
+        self.new = DiffSide(new_path, new=True)
+        self.headers: list[str] = []
+        self.binary = False
+
+    def append_header(self, line: str) -> None:
+        """Append the given line to the list of headers for this file."""
+        self.headers.append(line)
+
+    @property
+    def is_complete(self) -> bool:
+        """True if the diff is complete, otherwise False."""
+        return self.old.is_complete and self.new.is_complete
+
+
+class DiffSide:
+    """Parsed diff for a single 'side' of a single file."""
+    def __init__(self, path: str, new: bool) -> None:
+        self.path = path
+        self.new = new
+        self.prefix = '+' if self.new else '-'
+        self.eof_newline = True
+        self.exists = True
+
+        self.lines: list[tuple[int, str]] = []
+        self.lines_and_context: list[tuple[int, str]] = []
+        self.ranges: list[tuple[int, int]] = []
+
+        self._next_line_number = 0
+        self._lines_remaining = 0
+        self._range_start = 0
+
+    def set_start(self, line_start: int, line_count: int) -> None:
+        """Set the starting line and line count."""
+        self._next_line_number = line_start
+        self._lines_remaining = line_count
+        self._range_start = 0
+
+    def append(self, line: str) -> None:
+        """Append the given line."""
+        if self._lines_remaining <= 0:
+            raise Exception('Diff range overflow.')
+
+        entry = self._next_line_number, line
+
+        if line.startswith(' '):
+            pass
+        elif line.startswith(self.prefix):
+            self.lines.append(entry)
+
+            if not self._range_start:
+                self._range_start = self._next_line_number
+        else:
+            raise Exception('Unexpected diff content prefix.')
+
+        self.lines_and_context.append(entry)
+
+        self._lines_remaining -= 1
+
+        if self._range_start:
+            if self.is_complete:
+                range_end = self._next_line_number
+            elif line.startswith(' '):
+                range_end = self._next_line_number - 1
+            else:
+                range_end = 0
+
+            if range_end:
+                self.ranges.append((self._range_start, range_end))
+                self._range_start = 0
+
+        self._next_line_number += 1
+
+    @property
+    def is_complete(self) -> bool:
+        """True if the diff is complete, otherwise False."""
+        return self._lines_remaining == 0
+
+    def format_lines(self, context: bool = True) -> list[str]:
+        """Format the diff and return a list of lines, optionally including context."""
+        if context:
+            lines = self.lines_and_context
+        else:
+            lines = self.lines
+
+        return ['%s:%4d %s' % (self.path, line[0], line[1]) for line in lines]
+
+
+class DiffParser:
+    """Parse diff lines."""
+    def __init__(self, lines: list[str]) -> None:
+        self.lines = lines
+        self.files: list[FileDiff] = []
+
+        self.action = self.process_start
+        self.line_number = 0
+        self.previous_line: t.Optional[str] = None
+        self.line: t.Optional[str] = None
+        self.file: t.Optional[FileDiff] = None
+
+        for self.line in self.lines:
+            self.line_number += 1
+
+            try:
+                self.action()
+            except Exception as ex:
+                message = textwrap.dedent('''
+                %s
+
+                     Line: %d
+                 Previous: %s
+                  Current: %s
+                %s
+                ''').strip() % (
+                    ex,
+                    self.line_number,
+                    self.previous_line or '',
+                    self.line or '',
+                    traceback.format_exc(),
+                )
+
+                raise ApplicationError(message.strip())
+
+            self.previous_line = self.line
+
+        self.complete_file()
+
+    def process_start(self) -> None:
+        """Process a diff start line."""
+        self.complete_file()
+
+        match = re.search(r'^diff --git "?(?:a/)?(?P<old_path>.*)"? "?(?:b/)?(?P<new_path>.*)"?$', self.line)
+
+        if not match:
+            raise Exception('Unexpected diff start line.')
+
+        self.file = FileDiff(match.group('old_path'), match.group('new_path'))
+        self.action = self.process_continue
+
+    def process_range(self) -> None:
+        """Process a diff range line."""
+        match = re.search(r'^@@ -((?P<old_start>[0-9]+),)?(?P<old_count>[0-9]+) \+((?P<new_start>[0-9]+),)?(?P<new_count>[0-9]+) @@', self.line)
+
+        if not match:
+            raise Exception('Unexpected diff range line.')
+
+        self.file.old.set_start(int(match.group('old_start') or 1), int(match.group('old_count')))
+        self.file.new.set_start(int(match.group('new_start') or 1), int(match.group('new_count')))
+        self.action = self.process_content
+
+    def process_continue(self) -> None:
+        """Process a diff start, range or header line."""
+        if self.line.startswith('diff '):
+            self.process_start()
+        elif self.line.startswith('@@ '):
+            self.process_range()
+        else:
+            self.process_header()
+
+    def process_header(self) -> None:
+        """Process a diff header line."""
+        if self.line.startswith('Binary files '):
+            self.file.binary = True
+        elif self.line == '--- /dev/null':
+            self.file.old.exists = False
+        elif self.line == '+++ /dev/null':
+            self.file.new.exists = False
+        else:
+            self.file.append_header(self.line)
+
+    def process_content(self) -> None:
+        """Process a diff content line."""
+        if self.line == r'\ No newline at end of file':
+            if self.previous_line.startswith(' '):
+                self.file.old.eof_newline = False
+                self.file.new.eof_newline = False
+            elif self.previous_line.startswith('-'):
+                self.file.old.eof_newline = False
+            elif self.previous_line.startswith('+'):
+                self.file.new.eof_newline = False
+            else:
+                raise Exception('Unexpected previous diff content line.')
+
+            return
+
+        if self.file.is_complete:
+            self.process_continue()
+            return
+
+        if self.line.startswith(' '):
+            self.file.old.append(self.line)
+            self.file.new.append(self.line)
+        elif self.line.startswith('-'):
+            self.file.old.append(self.line)
+        elif self.line.startswith('+'):
+            self.file.new.append(self.line)
+        else:
+            raise Exception('Unexpected diff content line.')
+
+    def complete_file(self) -> None:
+        """Complete processing of the current file, if any."""
+        if not self.file:
+            return
+
+        self.files.append(self.file)