added handling for extremely weird edge case behavior for dockerignore

Author: james-rl

src/runloop_api_client/lib/_ignore.py

@@ -322,7 +322,6 @@ class DockerIgnoreMatcher(IgnoreMatcher):
 
     def iter_paths(self, root: Path) -> Iterable[Path]:
         """Yield non-ignored files under ``root`` honoring Docker-style patterns."""
-
         root = root.resolve()
 
         all_patterns: list[str] = []
@@ -338,9 +337,25 @@ def iter_paths(self, root: Path) -> Iterable[Path]:
                 raise FileNotFoundError(f"Ignore file does not exist: {ignore_path}")
             all_patterns.extend(read_ignorefile(ignore_path))
 
-        # 3) Optional inline patterns appended last.
+        # 3) Optional inline patterns appended last using same rules as .dockerignore
+        # Some extra handling here for trailing slashes that is different from .gitignore.
         if self.patterns:
-            all_patterns.extend(self.patterns)
+            for raw in self.patterns:
+                if not raw:
+                    continue
+
+                invert = raw[0] == "!"
+                pattern = raw[1:].strip() if invert else raw.strip()
+
+                if pattern:
+                    pattern = os.path.normpath(pattern)
+                    pattern = pattern.replace(os.sep, "/")
+                    if len(pattern) > 1 and pattern[0] == "/":
+                        pattern = pattern[1:]
+
+                normalized = f"!{pattern}" if invert else pattern
+                if normalized:
+                    all_patterns.append(normalized)
 
         compiled: list[IgnorePattern] = compile_ignore(all_patterns)
         return iter_included_files(root, patterns=compiled)

tests/test_utils/test_context_loader.py

@@ -79,6 +79,31 @@ def test_iter_build_context_files_respects_dockerignore(tmp_path: Path):
     assert "build/ignored.txt" not in files
 
 
+def test_optional_patterns_trailing_slash_matches_file_in_context(tmp_path: Path) -> None:
+    """Inline ignore patterns should mirror .dockerignore trailing-slash behavior.
+
+    Patterns like '/foo/bar/' provided via the optional ``ignore=`` parameter
+    should exclude a file at 'foo/bar' in the build context, matching Docker's
+    patternmatcher semantics where trailing slashes are not directory-only.
+    """
+
+    root = tmp_path
+    foo = root / "foo"
+    foo.mkdir()
+    (foo / "bar").write_text("ignored", encoding="utf-8")
+    (root / "keep.txt").write_text("keep", encoding="utf-8")
+
+    # Use build_docker_context_tar with an inline pattern that includes a
+    # trailing slash; this should still exclude the file at 'foo/bar'.
+    tar_bytes = build_docker_context_tar(root, ignore=["/foo/bar/"])
+
+    with tarfile.open(fileobj=io.BytesIO(tar_bytes), mode="r:gz") as tf:
+        names = {m.name for m in tf.getmembers()}
+
+    assert "keep.txt" in names
+    assert "foo/bar" not in names
+
+
 def test_is_ignored_directory_pattern_affects_directory_entry_only() -> None:
     """Directory patterns apply directly to directory entries, not to children."""