fix: determine a better path for a new TranslateSkel (#1367)

The problem was on the one hand that the path was first determined in
`__str__`, which means that it is not the position where the translate
object was created, but where it is converted to a string (this can also
be in the renderer). I have therefore moved this to `__init__`.

Furthermore, the stack loaded in `walk_stack()` skipped too many frames
(we actually need the first frame directly), so this couldn't work
either -- except for Jinja. Now we load the stack explicitly from the
top.

src/viur/core/i18n.py

@@ -74,12 +74,14 @@
 on your own. Just use the TranslateSkel).
 """  # FIXME: grammar, rst syntax
 import datetime
-import jinja2.ext as jinja2
 import logging
+import sys
 import traceback
 import typing as t
 from pathlib import Path
 
+import jinja2.ext as jinja2
+
 from viur.core import current, db, languages, tasks
 from viur.core.config import conf
 
@@ -157,6 +159,8 @@ class translate:
         "translationCache",
         "force_lang",
         "public",
+        "filename",
+        "lineno",
     )
 
     def __init__(
@@ -166,6 +170,7 @@ def __init__(
         hint: str = None,
         force_lang: str = None,
         public: bool = False,
+        caller_is_jinja: bool = False,
     ):
         """
         :param key: The unique key defining this text fragment.
@@ -178,59 +183,57 @@ def __init__(
             target language.
         :param force_lang: Use this language instead the one of the request.
         :param public: Flag for public translations, which can be obtained via /json/_translate/get_public.
+        :param caller_is_jinja: Is the call caused by our jinja method?
         """
         super().__init__()
         if not isinstance(key, str):
             logging.warning(f"Got non-string (type {type(key)}) as {key=}!", exc_info=True)
+        if force_lang is not None and force_lang not in conf.i18n.available_dialects:
+            raise ValueError(f"The language {force_lang=} is not available")
+
         key = str(key)  # ensure key is a str
         self.key = key.lower()
         self.defaultText = defaultText or key
         self.hint = hint
-
         self.translationCache = None
-        if force_lang is not None and force_lang not in conf.i18n.available_dialects:
-            raise ValueError(f"The language {force_lang=} is not available")
-
         self.force_lang = force_lang
         self.public = public
+        self.filename, self.lineno = None, None
+
+        if self.key not in systemTranslations and conf.i18n.add_missing_translations:
+            # This translation seems to be new and should be added
+            for frame, line in traceback.walk_stack(sys._getframe(0).f_back):
+                if self.filename is None:
+                    # Use the first frame as fallback.
+                    # In case of calling this class directly,
+                    # this is anyway the caller we're looking for.
+                    self.filename = frame.f_code.co_filename
+                    self.lineno = frame.f_lineno
+                    if not caller_is_jinja:
+                        break
+                if caller_is_jinja and not frame.f_code.co_filename.endswith(".py"):
+                    # Look for the latest html, macro (not py) where the
+                    # translate method has been used, that's our caller
+                    self.filename = frame.f_code.co_filename
+                    self.lineno = line
+                    break
 
     def __repr__(self) -> str:
         return f"<translate object for {self.key} with force_lang={self.force_lang}>"
 
-
     def __str__(self) -> str:
         if self.translationCache is None:
             global systemTranslations
 
-            from viur.core.render.html.env.viur import translate as jinja_translate
-
             if self.key not in systemTranslations and conf.i18n.add_missing_translations:
                 # This translation seems to be new and should be added
-                filename = lineno = None
-                is_jinja = False
-                for frame, line in traceback.walk_stack(None):
-                    if filename is None:
-                        # Use the first frame as fallback.
-                        # In case of calling this class directly,
-                        # this is anyway the caller we're looking for.
-                        filename = frame.f_code.co_filename
-                        lineno = frame.f_lineno
-                    if frame.f_code == jinja_translate.__code__:
-                        # The call was caused by our jinja method
-                        is_jinja = True
-                    if is_jinja and not frame.f_code.co_filename.endswith(".py"):
-                        # Look for the latest html, macro (not py) where the
-                        # translate method has been used, that's our caller
-                        filename = frame.f_code.co_filename
-                        lineno = line
-                        break
 
                 add_missing_translation(
                     key=self.key,
                     hint=self.hint,
                     default_text=self.defaultText,
-                    filename=filename,
-                    lineno=lineno,
+                    filename=self.filename,
+                    lineno=self.lineno,
                     public=self.public,
                 )
 

src/viur/core/render/html/env/viur.py

@@ -34,7 +34,7 @@ def translate(
 
     See also :class:`core.i18n.TranslationExtension`.
     """
-    return translate_class(key, default_text, hint, force_lang)(**kwargs)
+    return translate_class(key, default_text, hint, force_lang, caller_is_jinja=True)(**kwargs)
 
 
 @jinjaGlobalFunction