context: fix duplicate path error

search_dirs can contain duplicate path if YANGPATH envvar is used.
With libyang1, we can add several time the same searchdir without
problem but with libyang2, ly_ctx_set_searchdir returns an error if we
add a path already existant.

To fix it, we now pass the search dir directly when creating the
context.

Author: jeanseb6wind

libyang/context.py

@@ -45,8 +45,21 @@ def __init__(
         self.cdata = None
         ctx = ffi.new("struct ly_ctx **")
 
+        search_paths = []
+        if "YANGPATH" in os.environ:
+            search_paths.extend(os.environ["YANGPATH"].strip(": \t\r\n'\"").split(":"))
+        elif "YANG_MODPATH" in os.environ:
+            search_paths.extend(
+                os.environ["YANG_MODPATH"].strip(": \t\r\n'\"").split(":")
+            )
+        if search_path:
+            search_paths.extend(search_path.strip(": \t\r\n'\"").split(":"))
+
+        search_paths = [path for path in search_paths if os.path.isdir(path)]
+        search_path = ":".join(search_paths) if search_paths else None
+
         if yanglib_path is None:
-            if lib.ly_ctx_new(ffi.NULL, options, ctx) != lib.LY_SUCCESS:
+            if lib.ly_ctx_new(str2c(search_path), options, ctx) != lib.LY_SUCCESS:
                 raise self.error("cannot create context")
         else:
             if yanglib_fmt == "json":
@@ -66,25 +79,6 @@ def __init__(
         if not self.cdata:
             raise self.error("cannot create context")
 
-        search_dirs = []
-        if "YANGPATH" in os.environ:
-            search_dirs.extend(os.environ["YANGPATH"].strip(": \t\r\n'\"").split(":"))
-        elif "YANG_MODPATH" in os.environ:
-            search_dirs.extend(
-                os.environ["YANG_MODPATH"].strip(": \t\r\n'\"").split(":")
-            )
-        if search_path:
-            search_dirs.extend(search_path.strip(": \t\r\n'\"").split(":"))
-
-        if yanglib_path:
-            return
-
-        for path in search_dirs:
-            if not os.path.isdir(path):
-                continue
-            if lib.ly_ctx_set_searchdir(self.cdata, str2c(path)) != 0:
-                raise self.error("cannot set search dir")
-
     def get_yanglib_data(self, content_id_format=""):
         dnode = ffi.new("struct lyd_node **")
         ret = lib.ly_ctx_get_yanglib_data(self.cdata, dnode, str2c(content_id_format))

tests/test_context.py

@@ -29,6 +29,13 @@ def test_ctx_dir(self):
         with Context(YANG_DIR) as ctx:
             self.assertIsNot(ctx, None)
 
+    def test_ctx_duplicate_searchpath(self):
+        duplicate_search_path = ":".join([YANG_DIR, YANG_DIR])
+        try:
+            Context(duplicate_search_path)
+        except LibyangError:
+            self.fail("Context.__init__ should not raise LibyangError")
+
     def test_ctx_invalid_dir(self):
         with Context("/does/not/exist") as ctx:
             self.assertIsNot(ctx, None)