Translations (MO): Contextual translation can override non-contextual one

[cogk]

(low-priority bug /cc @barredterra)

Explanation

This bug is introduced when catalogs are merged across applications, because of the following lines:

frappe/frappe/gettext/translate.py

Lines 302 to 304 in 9e8808f

	if m.id not in translations:
	# better a translation with context than no translation
	translations[m.id] = m.string

Because intermediary dicts (1 per app) are merged in order, then a later de-contextualized translation (= a fallback) can overwrite a non-contextual one, which should be of a higher priority.

frappe/frappe/translate.py

Lines 176 to 178 in 9e8808f

	for app in apps or frappe.get_installed_apps(_ensure_on_bench=True):
	translations.update(get_translations_from_csv(lang, app) or {})
	translations.update(get_translations_from_mo(lang, app) or {})

Example

The following PO files of two different applications:

# app1.po
# no context
msgid   "FROM"
msgstr  "From"

# app2.po
msgctxt "Communication"
msgid   "FROM"
msgstr  "Communication sent by"

Will be converted to these two dicts:

app1_translations = {
  "FROM": "From",
}

app2_translations = {
  "FROM": "Communication sent by",  # 🚨 this is the bug
  "FROM:Communication": "Communication sent by",
}

Which, when merged in order, won't produce the expected result.

Expected

_("FROM")  # -> From
_("FROM", context="Communication")  # -> Communication sent by

Actual

_("FROM")  # -> Communication sent by
_("FROM", context="Communication")  # -> Communication sent by

[barredterra]

Is it enough to just remove these three lines?

[cogk]

I haven't checked yet, but I believe removing them would fix the bug 👍