gh-130453: pygettext: Allow overriding default keywords when using --keyword (GH-130709)

Lib/test/test_tools/i18n_data/custom_keywords.pot

@@ -15,31 +15,37 @@ msgstr ""
 "Generated-By: pygettext.py 1.5\n"
 
 
-#: custom_keywords.py:9 custom_keywords.py:10
+#: custom_keywords.py:10 custom_keywords.py:11
 msgid "bar"
 msgstr ""
 
-#: custom_keywords.py:12
+#: custom_keywords.py:13
 msgid "cat"
 msgid_plural "cats"
 msgstr[0] ""
 msgstr[1] ""
 
-#: custom_keywords.py:13
+#: custom_keywords.py:14
 msgid "dog"
 msgid_plural "dogs"
 msgstr[0] ""
 msgstr[1] ""
 
-#: custom_keywords.py:15
+#: custom_keywords.py:16
 msgctxt "context"
 msgid "bar"
 msgstr ""
 
-#: custom_keywords.py:17
+#: custom_keywords.py:18
 msgctxt "context"
 msgid "cat"
 msgid_plural "cats"
 msgstr[0] ""
 msgstr[1] ""
 
+#: custom_keywords.py:34
+msgid "overridden"
+msgid_plural "default"
+msgstr[0] ""
+msgstr[1] ""
+

Lib/test/test_tools/i18n_data/custom_keywords.py

@@ -4,6 +4,7 @@
     pgettext as pfoo,
     npgettext as npfoo,
     gettext as bar,
+    gettext as _,
 )
 
 foo('bar')
@@ -28,3 +29,6 @@
 # 'npfoo' requires at least 3 arguments
 npfoo('context')
 npfoo('context', 'cat')
+
+# --keyword should override the default keyword
+_('overridden', 'default')

Lib/test/test_tools/test_i18n.py

@@ -525,7 +525,7 @@ def extract_from_snapshots():
         'comments.py': ('--add-comments=i18n:',),
         'custom_keywords.py': ('--keyword=foo', '--keyword=nfoo:1,2',
                                '--keyword=pfoo:1c,2',
-                               '--keyword=npfoo:1c,2,3'),
+                               '--keyword=npfoo:1c,2,3', '--keyword=_:1,2'),
     }
 
     for filename, args in snapshots.items():

Misc/NEWS.d/next/Tools-Demos/2025-02-28-23-24-03.gh-issue-130453.EK0Vk_.rst

@@ -0,0 +1 @@
+Make it possible to override default keywords in :program:`pygettext`.

Tools/i18n/pygettext.py

@@ -729,12 +729,15 @@ class Options:
 
     # calculate all keywords
     try:
-        options.keywords = dict(parse_spec(spec) for spec in options.keywords)
+        custom_keywords = dict(parse_spec(spec) for spec in options.keywords)
     except ValueError as e:
         print(e, file=sys.stderr)
         sys.exit(1)
+    options.keywords = {}
     if not no_default_keywords:
         options.keywords |= DEFAULTKEYWORDS
+    # custom keywords override default keywords
+    options.keywords |= custom_keywords
 
     # initialize list of strings to exclude
     if options.excludefilename: