cli pyproject updating (#12945)

`langchain app add` and `langchain app remove` will now keep the
dependencies list updated.

---------

Co-authored-by: Nuno Campos <nuno@boringbits.io>

libs/cli/langchain_cli/utils/pyproject.py

@@ -0,0 +1,45 @@
+from pathlib import Path
+from typing import Any, Dict, Iterable
+
+from tomlkit import dump, inline_table, load
+from tomlkit.items import InlineTable
+
+
+def _get_dep_inline_table(path: Path) -> InlineTable:
+    dep = inline_table()
+    dep.update({"path": str(path), "develop": True})
+    return dep
+
+
+def add_dependencies_to_pyproject_toml(
+    pyproject_toml: Path, local_editable_dependencies: Iterable[tuple[str, Path]]
+) -> None:
+    """Add dependencies to pyproject.toml."""
+    with open(pyproject_toml, encoding="utf-8") as f:
+        # tomlkit types aren't amazing - treat as Dict instead
+        pyproject: Dict[str, Any] = load(f)
+        pyproject["tool"]["poetry"]["dependencies"].update(
+            {
+                name: _get_dep_inline_table(loc.relative_to(pyproject_toml.parent))
+                for name, loc in local_editable_dependencies
+            }
+        )
+    with open(pyproject_toml, "w", encoding="utf-8") as f:
+        dump(pyproject, f)
+
+
+def remove_dependencies_from_pyproject_toml(
+    pyproject_toml: Path, local_editable_dependencies: Iterable[str]
+) -> None:
+    """Remove dependencies from pyproject.toml."""
+    with open(pyproject_toml, encoding="utf-8") as f:
+        pyproject: Dict[str, Any] = load(f)
+        # tomlkit types aren't amazing - treat as Dict instead
+        dependencies = pyproject["tool"]["poetry"]["dependencies"]
+        for name in local_editable_dependencies:
+            try:
+                del dependencies[name]
+            except KeyError:
+                pass
+    with open(pyproject_toml, "w", encoding="utf-8") as f:
+        dump(pyproject, f)