otk: detect circular imports

This commit adds detection of cirular imports.

src/otk/error.py

@@ -98,3 +98,9 @@ class TransformDirectiveUnknownError(TransformError):
     """Unknown directive."""
 
     pass
+
+
+class CircularIncludeError(OTKError):
+    """Cirtcular include detected."""
+
+    pass

src/otk/transform.py

@@ -13,17 +13,17 @@
 
 import itertools
 import logging
+import os
 import pathlib
 import re
 from typing import Any, List
 
 import yaml
 
 from . import tree
-from .constant import (NAME_VERSION, PREFIX, PREFIX_DEFINE, PREFIX_INCLUDE,
-                       PREFIX_OP, PREFIX_TARGET)
+from .constant import NAME_VERSION, PREFIX, PREFIX_DEFINE, PREFIX_INCLUDE, PREFIX_OP, PREFIX_TARGET
 from .context import Context, OSBuildContext
-from .error import TransformDirectiveTypeError, TransformDirectiveUnknownError
+from .error import CircularIncludeError, TransformDirectiveTypeError, TransformDirectiveUnknownError
 from .external import call
 from .traversal import State
 
@@ -65,7 +65,6 @@ def resolve_dict(ctx: Context, state: State, tree: dict[str, Any]) -> Any:
         if isinstance(val, str):
             val = substitute_vars(ctx, val)
         if is_directive(key):
-
             if key.startswith(PREFIX_DEFINE):
                 process_defines(ctx, state, val)
                 continue
@@ -170,20 +169,23 @@ def process_include(ctx: Context, state: State, path: pathlib.Path) -> dict:
     """
     # resolve 'path' relative to 'state.path'
     cur_path = state.path.parent
-    path = cur_path / pathlib.Path(path)
+    path = (cur_path / pathlib.Path(path)).resolve()
     try:
         with open(path, mode="r", encoding="utf=8") as fp:
             data = yaml.safe_load(fp)
     except FileNotFoundError as fnfe:
         raise FileNotFoundError(f"file {path} referenced from {state.path} was not found") from fnfe
 
     if data is not None:
+        if path in state.includes:
+            circle = [os.fspath(p) for p in state.includes]
+            raise CircularIncludeError(f"circular include from {circle}")
         new_state = state.copy(path=path)
+        new_state.includes.append(path)
         return resolve(ctx, new_state, data)
     return {}
 
 
-
 @tree.must_be(str)
 def include(ctx: Context, tree: Any) -> Any:
     """Include a separate file."""

src/otk/traversal.py

@@ -1,9 +1,12 @@
 class State:
-    def __init__(self, path, defines):
+    def __init__(self, path, defines, includes=None):
         self.path = path
         self.defines = defines
+        if includes is None:
+            includes = []
+        self.includes = includes
 
-    def copy(self, *, path=None, defines=None) -> "State":
+    def copy(self, *, path=None, defines=None, includes=None) -> "State":
         """
         Return a new State, optionally redefining the path and defines
         properties. Properties not defined in the args are (shallow) copied
@@ -16,5 +19,7 @@ def copy(self, *, path=None, defines=None) -> "State":
             path = self.path
         if defines is None:
             defines = self.defines
+        if includes is None:
+            includes = self.includes.copy()
 
-        return State(path, defines)
+        return State(path, defines, includes)

test/data/error/01-circular.err

@@ -0,0 +1 @@
+circular include from

test/data/error/01-circular.yaml

@@ -0,0 +1,4 @@
+otk.version: 1
+
+otk.target.osbuild.name:
+  otk.include: 01-circular/a.yaml

test/data/error/01-circular/a.yaml

@@ -0,0 +1 @@
+otk.include: b.yaml

test/data/error/01-circular/b.yaml

@@ -0,0 +1 @@
+otk.include: subdir/c.yaml

test/data/error/01-circular/subdir/c.yaml

@@ -0,0 +1 @@
+otk.include: ../a.yaml