Improve string concatenation (#12758)

Use implicit concatenation over ``+``, and combine some implicit concatenations
to a single string literal.

sphinx/domains/c/_parser.py

@@ -495,9 +495,11 @@ class DefinitionParser(BaseParser):
                 self.fail("Expected identifier in nested name, "
                           "got keyword: %s" % identifier)
             if self.matched_text in self.config.c_extra_keywords:
-                msg = "Expected identifier, got user-defined keyword: %s." \
-                      + " Remove it from c_extra_keywords to allow it as identifier.\n" \
-                      + "Currently c_extra_keywords is %s."
+                msg = (
+                    'Expected identifier, got user-defined keyword: %s.'
+                    ' Remove it from c_extra_keywords to allow it as identifier.\n'
+                    'Currently c_extra_keywords is %s.'
+                )
                 self.fail(msg % (self.matched_text,
                                  str(self.config.c_extra_keywords)))
             ident = ASTIdentifier(identifier)
@@ -670,9 +672,11 @@ class DefinitionParser(BaseParser):
                     self.fail("Expected identifier, "
                               "got keyword: %s" % self.matched_text)
                 if self.matched_text in self.config.c_extra_keywords:
-                    msg = "Expected identifier, got user-defined keyword: %s." \
-                          + " Remove it from c_extra_keywords to allow it as identifier.\n" \
-                          + "Currently c_extra_keywords is %s."
+                    msg = (
+                        'Expected identifier, got user-defined keyword: %s. '
+                        'Remove it from c_extra_keywords to allow it as identifier.\n'
+                        'Currently c_extra_keywords is %s.'
+                    )
                     self.fail(msg % (self.matched_text,
                                      str(self.config.c_extra_keywords)))
                 identifier = ASTIdentifier(self.matched_text)

sphinx/domains/cpp/_parser.py

@@ -1263,7 +1263,7 @@ class DefinitionParser(BaseParser):
                         if self.skip_string('('):
                             expr = self._parse_constant_expression(inTemplate=False)
                             if not expr:
-                                self.fail("Expected constant expression after '('" +
+                                self.fail("Expected constant expression after '('"
                                           " in explicit specifier.")
                             self.skip_ws()
                             if not self.skip_string(')'):
@@ -1972,13 +1972,14 @@ class DefinitionParser(BaseParser):
         if numArgs > numParams:
             numExtra = numArgs - numParams
             if not fullSpecShorthand and not isMemberInstantiation:
-                msg = "Too many template argument lists compared to parameter" \
-                    " lists. Argument lists: %d, Parameter lists: %d," \
-                    " Extra empty parameters lists prepended: %d." \
-                    % (numArgs, numParams, numExtra)
-                msg += " Declaration:\n\t"
+                msg = (
+                    f'Too many template argument lists compared to parameter lists. '
+                    f'Argument lists: {numArgs:d}, Parameter lists: {numParams:d}, '
+                    f'Extra empty parameters lists prepended: {numExtra:d}. '
+                    'Declaration:\n\t'
+                )
                 if templatePrefix:
-                    msg += "%s\n\t" % templatePrefix
+                    msg += f"{templatePrefix}\n\t"
                 msg += str(nestedName)
                 self.warn(msg)
 

sphinx/ext/apidoc.py

@@ -394,7 +394,7 @@ Note: By default this script will not overwrite already created files."""),
         'exclude_pattern',
         nargs='*',
         help=__(
-            'fnmatch-style file and/or directory patterns ' 'to exclude from generation'
+            'fnmatch-style file and/or directory patterns to exclude from generation'
         ),
     )
 
@@ -419,7 +419,7 @@ Note: By default this script will not overwrite already created files."""),
         dest='maxdepth',
         type=int,
         default=4,
-        help=__('maximum depth of submodules to show in the TOC ' '(default: 4)'),
+        help=__('maximum depth of submodules to show in the TOC (default: 4)'),
     )
     parser.add_argument(
         '-f',
@@ -435,8 +435,7 @@ Note: By default this script will not overwrite already created files."""),
         dest='followlinks',
         default=False,
         help=__(
-            'follow symbolic links. Powerful when combined '
-            'with collective.recipe.omelette.'
+            'follow symbolic links. Powerful when combined with collective.recipe.omelette.'
         ),
     )
     parser.add_argument(
@@ -490,15 +489,14 @@ Note: By default this script will not overwrite already created files."""),
         '--module-first',
         action='store_true',
         dest='modulefirst',
-        help=__('put module documentation before submodule ' 'documentation'),
+        help=__('put module documentation before submodule documentation'),
     )
     parser.add_argument(
         '--implicit-namespaces',
         action='store_true',
         dest='implicit_namespaces',
         help=__(
-            'interpret module paths according to PEP-0420 '
-            'implicit namespaces specification'
+            'interpret module paths according to PEP-0420 implicit namespaces specification'
         ),
     )
     parser.add_argument(
@@ -559,7 +557,7 @@ Note: By default this script will not overwrite already created files."""),
         action='store',
         dest='release',
         help=__(
-            'project release, used when --full is given, ' 'defaults to --doc-version'
+            'project release, used when --full is given, defaults to --doc-version'
         ),
     )
 

sphinx/ext/autosummary/generate.py

@@ -803,7 +803,7 @@ The format of the autosummary directive is documented in the
         action='store',
         dest='suffix',
         default='rst',
-        help=__('default suffix for files (default: ' '%(default)s)'),
+        help=__('default suffix for files (default: %(default)s)'),
     )
     parser.add_argument(
         '-t',
@@ -811,7 +811,7 @@ The format of the autosummary directive is documented in the
         action='store',
         dest='templates',
         default=None,
-        help=__('custom template directory (default: ' '%(default)s)'),
+        help=__('custom template directory (default: %(default)s)'),
     )
     parser.add_argument(
         '-i',
@@ -819,7 +819,7 @@ The format of the autosummary directive is documented in the
         action='store_true',
         dest='imported_members',
         default=False,
-        help=__('document imported members (default: ' '%(default)s)'),
+        help=__('document imported members (default: %(default)s)'),
     )
     parser.add_argument(
         '-a',

sphinx/ext/coverage.py

@@ -455,7 +455,7 @@ class CoverageBuilder(Builder):
                                     if self.app.quiet or self.app.warningiserror:
                                         for meth in methods:
                                             logger.warning(
-                                                __('undocumented python method:' +
+                                                __('undocumented python method:'
                                                    ' %s :: %s :: %s'),
                                                 name, class_name, meth)
                                     else:

sphinx/transforms/i18n.py

@@ -202,7 +202,7 @@ class _NodeUpdater:
         old_foot_refs = list(is_autofootnote_ref.findall(self.node))
         new_foot_refs = list(is_autofootnote_ref.findall(self.patch))
         self.compare_references(old_foot_refs, new_foot_refs,
-                                __('inconsistent footnote references in translated message.' +
+                                __('inconsistent footnote references in translated message.'
                                    ' original: {0}, translated: {1}'))
         old_foot_namerefs: dict[str, list[nodes.footnote_reference]] = {}
         for r in old_foot_refs:
@@ -242,7 +242,7 @@ class _NodeUpdater:
         old_refs = list(is_refnamed_ref.findall(self.node))
         new_refs = list(is_refnamed_ref.findall(self.patch))
         self.compare_references(old_refs, new_refs,
-                                __('inconsistent references in translated message.' +
+                                __('inconsistent references in translated message.'
                                    ' original: {0}, translated: {1}'))
         old_ref_names = [r['refname'] for r in old_refs]
         new_ref_names = [r['refname'] for r in new_refs]
@@ -267,7 +267,7 @@ class _NodeUpdater:
         new_foot_refs = list(is_refnamed_footnote_ref.findall(self.patch))
         refname_ids_map: dict[str, list[str]] = {}
         self.compare_references(old_foot_refs, new_foot_refs,
-                                __('inconsistent footnote references in translated message.' +
+                                __('inconsistent footnote references in translated message.'
                                    ' original: {0}, translated: {1}'))
         for oldf in old_foot_refs:
             refname_ids_map.setdefault(oldf["refname"], []).append(oldf["ids"])
@@ -282,7 +282,7 @@ class _NodeUpdater:
         old_cite_refs = list(is_citation_ref.findall(self.node))
         new_cite_refs = list(is_citation_ref.findall(self.patch))
         self.compare_references(old_cite_refs, new_cite_refs,
-                                __('inconsistent citation references in translated message.' +
+                                __('inconsistent citation references in translated message.'
                                    ' original: {0}, translated: {1}'))
         refname_ids_map: dict[str, list[str]] = {}
         for oldc in old_cite_refs:
@@ -299,7 +299,7 @@ class _NodeUpdater:
         old_xrefs = [*self.node.findall(addnodes.pending_xref)]
         new_xrefs = [*self.patch.findall(addnodes.pending_xref)]
         self.compare_references(old_xrefs, new_xrefs,
-                                __('inconsistent term references in translated message.' +
+                                __('inconsistent term references in translated message.'
                                    ' original: {0}, translated: {1}'))
 
         xref_reftarget_map: dict[tuple[str, str, str] | None, dict[str, Any]] = {}

tests/test_builders/test_build_html_code.py

@@ -41,6 +41,6 @@ def test_html_code_role(app):
         '<span class="k">pass</span>')
     assert ('<p>Inline <code class="code highlight python docutils literal highlight-python">' +
             common_content + '</code> code block</p>') in content
-    assert ('<div class="highlight-python notranslate">' +
+    assert ('<div class="highlight-python notranslate">'
             '<div class="highlight"><pre><span></span>' +
             common_content) in content

tests/test_builders/test_build_latex.py

@@ -1698,7 +1698,7 @@ def test_latex_code_role(app):
         r'\PYG{k}{pass}')
     assert (r'Inline \sphinxcode{\sphinxupquote{%' + '\n' +
             common_content + '%\n}} code block') in content
-    assert (r'\begin{sphinxVerbatim}[commandchars=\\\{\}]' +
+    assert (r'\begin{sphinxVerbatim}[commandchars=\\\{\}]'
             '\n' + common_content + '\n' + r'\end{sphinxVerbatim}') in content
 
 

tests/test_builders/test_build_warnings.py

@@ -45,8 +45,8 @@ def _check_warnings(expected_warnings: str, warning: str) -> None:
     warnings = strip_colors(re.sub(re.escape(os.sep) + '{1,2}', '/', warning))
     assert re.match(f'{expected_warnings}$', warnings), (
         "Warnings don't match:\n"
-        + f'--- Expected (regex):\n{expected_warnings}\n'
-        + f'--- Got:\n{warnings}'
+        f'--- Expected (regex):\n{expected_warnings}\n'
+        f'--- Got:\n{warnings}'
     )
     sys.modules.pop('autodoc_fodder', None)
 

tests/test_directives/test_directive_code.py

@@ -302,8 +302,8 @@ def test_code_block(app):
     assert len(code_block) > 0
     actual = code_block[0].text
     expect = (
-        "    def ruby?\n" +
-        "        false\n" +
+        "    def ruby?\n"
+        "        false\n"
         "    end"
     )
     assert actual == expect
@@ -333,8 +333,8 @@ def test_code_block_caption_latex(app):
     latex = (app.outdir / 'projectnamenotset.tex').read_text(encoding='utf8')
     caption = '\\sphinxSetupCaptionForVerbatim{caption \\sphinxstyleemphasis{test} rb}'
     label = '\\def\\sphinxLiteralBlockLabel{\\label{\\detokenize{caption:id1}}}'
-    link = '\\hyperref[\\detokenize{caption:name-test-rb}]' \
-           '{Listing \\ref{\\detokenize{caption:name-test-rb}}}'
+    link = ('\\hyperref[\\detokenize{caption:name-test-rb}]'
+            '{Listing \\ref{\\detokenize{caption:name-test-rb}}}')
     assert caption in latex
     assert label in latex
     assert link in latex
@@ -345,12 +345,12 @@ def test_code_block_namedlink_latex(app):
     app.build(force_all=True)
     latex = (app.outdir / 'projectnamenotset.tex').read_text(encoding='utf8')
     label1 = '\\def\\sphinxLiteralBlockLabel{\\label{\\detokenize{caption:name-test-rb}}}'
-    link1 = '\\hyperref[\\detokenize{caption:name-test-rb}]'\
-            '{\\sphinxcrossref{\\DUrole{std,std-ref}{Ruby}}'
+    link1 = ('\\hyperref[\\detokenize{caption:name-test-rb}]'
+             '{\\sphinxcrossref{\\DUrole{std,std-ref}{Ruby}}')
     label2 = ('\\def\\sphinxLiteralBlockLabel'
               '{\\label{\\detokenize{namedblocks:some-ruby-code}}}')
-    link2 = '\\hyperref[\\detokenize{namedblocks:some-ruby-code}]'\
-            '{\\sphinxcrossref{\\DUrole{std,std-ref}{the ruby code}}}'
+    link2 = ('\\hyperref[\\detokenize{namedblocks:some-ruby-code}]'
+             '{\\sphinxcrossref{\\DUrole{std,std-ref}{the ruby code}}}')
     assert label1 in latex
     assert link1 in latex
     assert label2 in latex
@@ -453,8 +453,8 @@ def test_literalinclude_caption_latex(app):
     latex = (app.outdir / 'projectnamenotset.tex').read_text(encoding='utf8')
     caption = '\\sphinxSetupCaptionForVerbatim{caption \\sphinxstylestrong{test} py}'
     label = '\\def\\sphinxLiteralBlockLabel{\\label{\\detokenize{caption:id2}}}'
-    link = '\\hyperref[\\detokenize{caption:name-test-py}]' \
-           '{Listing \\ref{\\detokenize{caption:name-test-py}}}'
+    link = ('\\hyperref[\\detokenize{caption:name-test-py}]'
+            '{Listing \\ref{\\detokenize{caption:name-test-py}}}')
     assert caption in latex
     assert label in latex
     assert link in latex
@@ -465,12 +465,12 @@ def test_literalinclude_namedlink_latex(app):
     app.build(filenames='index')
     latex = (app.outdir / 'projectnamenotset.tex').read_text(encoding='utf8')
     label1 = '\\def\\sphinxLiteralBlockLabel{\\label{\\detokenize{caption:name-test-py}}}'
-    link1 = '\\hyperref[\\detokenize{caption:name-test-py}]'\
-            '{\\sphinxcrossref{\\DUrole{std,std-ref}{Python}}'
+    link1 = ('\\hyperref[\\detokenize{caption:name-test-py}]'
+             '{\\sphinxcrossref{\\DUrole{std,std-ref}{Python}}')
     label2 = ('\\def\\sphinxLiteralBlockLabel'
               '{\\label{\\detokenize{namedblocks:some-python-code}}}')
-    link2 = '\\hyperref[\\detokenize{namedblocks:some-python-code}]'\
-            '{\\sphinxcrossref{\\DUrole{std,std-ref}{the python code}}}'
+    link2 = ('\\hyperref[\\detokenize{namedblocks:some-python-code}]'
+             '{\\sphinxcrossref{\\DUrole{std,std-ref}{the python code}}}')
     assert label1 in latex
     assert link1 in latex
     assert label2 in latex

tests/test_directives/test_directive_object_description.py

@@ -55,8 +55,8 @@ def test_object_description_sections(app):
 
 
 def test_object_description_content_line_number(app):
-    text = (".. py:function:: foo(bar)\n" +
-            "\n" +
+    text = (".. py:function:: foo(bar)\n"
+            "\n"
             "   Some link here: :ref:`abc`\n")
     doc = restructuredtext.parse(app, text)
     xrefs = list(doc.findall(condition=addnodes.pending_xref))

tests/test_domains/test_domain_cpp.py

@@ -485,8 +485,8 @@ def test_domain_cpp_ast_function_definitions():
     check('function', 'bool namespaced::theclass::method(arg1, arg2)',
           {1: "namespaced::theclass::method__arg1.arg2",
            2: "N10namespaced8theclass6methodE4arg14arg2"})
-    x = 'std::vector<std::pair<std::string, int>> &module::test(register int ' \
-        'foo, bar, std::string baz = "foobar, blah, bleh") const = 0'
+    x = ('std::vector<std::pair<std::string, int>> &module::test(register int '
+         'foo, bar, std::string baz = "foobar, blah, bleh") const = 0')
     check('function', x, {1: "module::test__i.bar.ssC",
                           2: "NK6module4testEi3barNSt6stringE"})
     check('function', 'void f(std::pair<A, B>)',
@@ -557,8 +557,8 @@ def test_domain_cpp_ast_function_definitions():
     check('function', 'MyClass::pointer MyClass::operator->()',
           {1: "MyClass::pointer-operator", 2: "N7MyClassptEv"})
 
-    x = 'std::vector<std::pair<std::string, int>> &module::test(register int ' \
-        'foo, bar[n], std::string baz = "foobar, blah, bleh") const = 0'
+    x = ('std::vector<std::pair<std::string, int>> &module::test(register int '
+         'foo, bar[n], std::string baz = "foobar, blah, bleh") const = 0')
     check('function', x, {1: "module::test__i.barA.ssC",
                           2: "NK6module4testEiAn_3barNSt6stringE",
                           3: "NK6module4testEiA1n_3barNSt6stringE"})
@@ -920,12 +920,12 @@ def test_domain_cpp_ast_requires_clauses():
     check('function', 'template<typename T> requires A && B || C and D void f()',
           {4: 'I0EIQooaa1A1Baa1C1DE1fvv'})
     check('function',
-          'template<typename T> requires R<T> ' +
-          'template<typename U> requires S<T> ' +
+          'template<typename T> requires R<T> '
+          'template<typename U> requires S<T> '
           'void A<T>::f() requires B',
           {4: 'I0EIQ1RI1TEEI0EIQaa1SI1TE1BEN1A1fEvv'})
     check('function',
-          'template<template<typename T> requires R<T> typename X> ' +
+          'template<template<typename T> requires R<T> typename X> '
           'void f()',
           {2: 'II0EIQ1RI1TEE0E1fv', 4: 'II0EIQ1RI1TEE0E1fvv'})
     check('type',

tests/test_domains/test_domain_js.py

@@ -234,8 +234,8 @@ def test_no_index_entry(app):
 
 
 def test_module_content_line_number(app):
-    text = (".. js:module:: foo\n" +
-            "\n" +
+    text = (".. js:module:: foo\n"
+            "\n"
             "   Some link here: :ref:`abc`\n")
     doc = restructuredtext.parse(app, text)
     xrefs = list(doc.findall(condition=addnodes.pending_xref))

tests/test_domains/test_domain_py.py

@@ -691,8 +691,8 @@ def test_domain_py_python_maximum_signature_line_length_in_text(app):
 
 
 def test_module_content_line_number(app):
-    text = (".. py:module:: foo\n" +
-            "\n" +
+    text = (".. py:module:: foo\n"
+            "\n"
             "   Some link here: :ref:`abc`\n")
     doc = restructuredtext.parse(app, text)
     xrefs = list(doc.findall(condition=addnodes.pending_xref))

tests/test_extensions/test_ext_apidoc.py

@@ -322,9 +322,10 @@ def test_toc_all_references_should_exist_pep420_enabled(make_app, apidoc):
         if not (outdir / filename).is_file():
             missing_files.append(filename)
 
-    assert len(missing_files) == 0, \
-        'File(s) referenced in TOC not found: {}\n' \
-        'TOC:\n{}'.format(", ".join(missing_files), toc)
+    all_missing = ', '.join(missing_files)
+    assert len(missing_files) == 0, (
+        f'File(s) referenced in TOC not found: {all_missing}\nTOC:\n{toc}'
+    )
 
 
 @pytest.mark.apidoc(
@@ -352,9 +353,10 @@ def test_toc_all_references_should_exist_pep420_disabled(make_app, apidoc):
         if not (outdir / filename).is_file():
             missing_files.append(filename)
 
-    assert len(missing_files) == 0, \
-        'File(s) referenced in TOC not found: {}\n' \
-        'TOC:\n{}'.format(", ".join(missing_files), toc)
+    all_missing = ', '.join(missing_files)
+    assert len(missing_files) == 0, (
+        f'File(s) referenced in TOC not found: {all_missing}\nTOC:\n{toc}'
+    )
 
 
 def extract_toc(path):

tests/test_extensions/test_ext_autosummary.py

@@ -186,8 +186,9 @@ def test_get_items_summary(make_app, app_params):
         'C.C2': 'This is a nested inner class docstring',
     }
     for key, expected in expected_values.items():
-        assert autosummary_items[key][2] == expected, 'Summary for %s was %r -'\
-            ' expected %r' % (key, autosummary_items[key], expected)
+        assert autosummary_items[key][2] == expected, (
+            f'Summary for {key} was {autosummary_items[key]!r} - expected {expected!r}'
+        )
 
     # check an item in detail
     assert 'func' in autosummary_items

tests/test_extensions/test_ext_ifconfig.py

@@ -17,8 +17,8 @@ def test_ifconfig(app):
 
 def test_ifconfig_content_line_number(app):
     app.setup_extension("sphinx.ext.ifconfig")
-    text = (".. ifconfig:: confval1\n" +
-            "\n" +
+    text = (".. ifconfig:: confval1\n"
+            "\n"
             "   Some link here: :ref:`abc`\n")
     doc = restructuredtext.parse(app, text)
     xrefs = list(doc.findall(condition=addnodes.pending_xref))

tests/test_extensions/test_ext_viewcode.py

@@ -15,7 +15,7 @@ if TYPE_CHECKING:
 def check_viewcode_output(app: SphinxTestApp) -> str:
     warnings = re.sub(r'\\+', '/', app.warning.getvalue())
     assert re.findall(
-        r"index.rst:\d+: WARNING: Object named 'func1' not found in include " +
+        r"index.rst:\d+: WARNING: Object named 'func1' not found in include "
         r"file .*/spam/__init__.py'",
         warnings,
     )
@@ -131,7 +131,7 @@ def test_local_source_files(app):
 
     warnings = re.sub(r'\\+', '/', app.warning.getvalue())
     assert re.findall(
-        r"index.rst:\d+: WARNING: Object named 'func1' not found in include " +
+        r"index.rst:\d+: WARNING: Object named 'func1' not found in include "
         r"file .*/not_a_package/__init__.py'",
         warnings,
     )

tests/test_intl/test_intl.py

@@ -1307,8 +1307,7 @@ def test_xml_label_targets(app):
     assert_elem(
         para3[0],
         ['X', 'bridge label',
-         'IS NOT TRANSLATABLE BUT LINKED TO TRANSLATED ' +
-         'SECTION TITLE.'],
+         'IS NOT TRANSLATABLE BUT LINKED TO TRANSLATED SECTION TITLE.'],
         ['label-bridged-target-section'])
     assert_elem(
         para3[1],