Support placeholders for years in copyright

doc/conf.py

@@ -3,7 +3,6 @@
 
 import os
 import re
-import time
 from typing import TYPE_CHECKING
 
 from sphinx import __display_version__
@@ -27,7 +26,7 @@
 exclude_patterns = ['_build']
 
 project = 'Sphinx'
-copyright = f'2007-{time.strftime("%Y")}, the Sphinx developers'
+copyright = '2007-%Y, the Sphinx developers'
 release = version = __display_version__
 show_authors = True
 nitpicky = True

sphinx/config.py

@@ -626,27 +626,38 @@ def correct_copyright_year(_app: Sphinx, config: Config) -> None:
     See https://reproducible-builds.org/specs/source-date-epoch/
     """
     if source_date_epoch := int(getenv('SOURCE_DATE_EPOCH', '0')):
-        source_date_epoch_year = time.gmtime(source_date_epoch).tm_year
+        replace_year = time.gmtime(source_date_epoch).tm_year
     else:
-        return
+        replace_year = time.gmtime().tm_year
 
     # If the current year is the replacement year, there's no work to do.
     # We also skip replacement years that are in the future.
     current_year = time.localtime().tm_year
-    if current_year <= source_date_epoch_year:
+    if current_year <= replace_year:
         return
 
     current_yr = str(current_year)
-    replace_yr = str(source_date_epoch_year)
+    replace_yr = str(replace_year)
+    year_short = str(replace_year % 100)
     for k in ('copyright', 'epub_copyright'):
         if k in config:
             value: str | Sequence[str] = config[k]
             if isinstance(value, str):
-                config[k] = _substitute_copyright_year(value, current_yr, replace_yr)
+                if '%y' in value or '%Y' in value:
+                    # new-style placeholder replacement
+                    config[k] = value.replace('%Y', replace_yr).replace('%y', year_short)
+                else:
+                    config[k] = _substitute_copyright_year(value, current_yr, replace_yr)
             else:
-                items = (
-                    _substitute_copyright_year(x, current_yr, replace_yr) for x in value
-                )
+                if any('%y' in line or '%Y' in line for line in value):
+                    # new-style placeholder replacement
+                    items = (
+                        x.replace('%Y', replace_yr).replace('%y', year_short) for x in value
+                    )
+                else:
+                    items = (
+                        _substitute_copyright_year(x, current_yr, replace_yr) for x in value
+                    )
                 config[k] = type(value)(items)  # type: ignore[call-arg]