Merge 'upstream/master' (70a58c5)

.clang-format

@@ -3,7 +3,6 @@
 # clang-format --style=llvm --dump-config
 BasedOnStyle: LLVM
 AccessModifierOffset: -4
-AlignConsecutiveAssignments: true
 AlwaysBreakTemplateDeclarations: Yes
 BinPackArguments: false
 BinPackParameters: false
@@ -15,7 +14,6 @@ IndentPPDirectives: AfterHash
 IndentWidth: 4
 Language: Cpp
 SpaceAfterCStyleCast: true
-# SpaceInEmptyBlock: true # too new
 Standard: Cpp11
 TabWidth: 4
 ...

.clang-tidy

@@ -1,13 +1,65 @@
 FormatStyle: file
 
 Checks: '
+*bugprone*,
+cppcoreguidelines-init-variables,
+cppcoreguidelines-slicing,
+clang-analyzer-optin.cplusplus.VirtualCall,
+google-explicit-constructor,
 llvm-namespace-comment,
-modernize-use-override,
-readability-container-size-empty,
-modernize-use-using,
-modernize-use-equals-default,
+misc-misplaced-const,
+misc-non-copyable-objects,
+misc-static-assert,
+misc-throw-by-value-catch-by-reference,
+misc-uniqueptr-reset-release,
+misc-unused-parameters,
+modernize-avoid-bind,
+modernize-make-shared,
+modernize-redundant-void-arg,
+modernize-replace-auto-ptr,
+modernize-replace-disallow-copy-and-assign-macro,
+modernize-replace-random-shuffle,
+modernize-shrink-to-fit,
 modernize-use-auto,
+modernize-use-bool-literals,
+modernize-use-equals-default,
+modernize-use-equals-delete,
+modernize-use-default-member-init,
+modernize-use-noexcept,
 modernize-use-emplace,
+modernize-use-override,
+modernize-use-using,
+*performance*,
+readability-avoid-const-params-in-decls,
+readability-const-return-type,
+readability-container-size-empty,
+readability-delete-null-pointer,
+readability-else-after-return,
+readability-implicit-bool-conversion,
+readability-make-member-function-const,
+readability-misplaced-array-index,
+readability-non-const-parameter,
+readability-redundant-function-ptr-dereference,
+readability-redundant-smartptr-get,
+readability-redundant-string-cstr,
+readability-simplify-subscript-expr,
+readability-static-accessed-through-instance,
+readability-static-definition-in-anonymous-namespace,
+readability-string-compare,
+readability-uniqueptr-delete-release,
+-bugprone-exception-escape,
+-bugprone-reserved-identifier,
+-bugprone-unused-raii,
 '
 
+CheckOptions:
+- key:             performance-for-range-copy.WarnOnAllAutoCopies
+  value:           true
+- key:             performance-unnecessary-value-param.AllowedTypes
+  value:           'exception_ptr$;'
+- key:             readability-implicit-bool-conversion.AllowPointerConditions
+  value:           true
+
 HeaderFilterRegex: 'pybind11/.*h'
+
+WarningsAsErrors: '*'

.github/CODEOWNERS

@@ -0,0 +1,9 @@
+*.cmake @henryiii
+CMakeLists.txt @henryiii
+*.yml @henryiii
+*.yaml @henryiii
+/tools/ @henryiii
+/pybind11/ @henryiii
+noxfile.py @henryiii
+.clang-format @henryiii
+.clang-tidy @henryiii

.github/CONTRIBUTING.md

@@ -53,6 +53,33 @@ derivative works thereof, in binary and source code form.
 
 ## Development of pybind11
 
+### Quick setup
+
+To setup a quick development environment, use [`nox`](https://nox.thea.codes).
+This will allow you to do some common tasks with minimal setup effort, but will
+take more time to run and be less flexible than a full development environment.
+If you use [`pipx run nox`](https://pipx.pypa.io), you don't even need to
+install `nox`. Examples:
+
+```bash
+# List all available sessions
+nox -l
+
+# Run linters
+nox -s lint
+
+# Run tests on Python 3.9
+nox -s tests-3.9
+
+# Build and preview docs
+nox -s docs -- serve
+
+# Build SDists and wheels
+nox -s build
+```
+
+### Full setup
+
 To setup an ideal development environment, run the following commands on a
 system with CMake 3.14+:
 
@@ -203,14 +230,15 @@ of the pybind11 repo.
 [`clang-tidy`][clang-tidy] performs deeper static code analyses and is
 more complex to run, compared to `clang-format`, but support for `clang-tidy`
 is built into the pybind11 CMake configuration. To run `clang-tidy`, the
-following recipe should work. Files will be modified in place, so you can
-use git to monitor the changes.
+following recipe should work. Run the `docker` command from the top-level
+directory inside your pybind11 git clone. Files will be modified in place,
+so you can use git to monitor the changes.
 
 ```bash
-docker run --rm -v $PWD:/pybind11 -it silkeh/clang:10
-apt-get update && apt-get install python3-dev python3-pytest
-cmake -S pybind11/ -B build -DCMAKE_CXX_CLANG_TIDY="$(which clang-tidy);-fix"
-cmake --build build
+docker run --rm -v $PWD:/mounted_pybind11 -it silkeh/clang:12
+apt-get update && apt-get install -y python3-dev python3-pytest
+cmake -S /mounted_pybind11/ -B build -DCMAKE_CXX_CLANG_TIDY="$(which clang-tidy);-fix" -DDOWNLOAD_EIGEN=ON -DDOWNLOAD_CATCH=ON -DCMAKE_CXX_STANDARD=17
+cmake --build build -j 2 -- --keep-going
 ```
 
 ### Include what you use

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -0,0 +1,45 @@
+name: Bug Report
+description: File an issue about a bug
+title: "[BUG]: "
+labels: [triage]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Maintainers will only make a best effort to triage PRs. Please do your best to make the issue as easy to act on as possible, and only open if clearly a problem with pybind11 (ask first if unsure).
+  - type: checkboxes
+    id: steps
+    attributes:
+      label: Required prerequisites
+      description: Make sure you've completed the following steps before submitting your issue -- thank you!
+      options:
+        - label: Make sure you've read the [documentation](https://pybind11.readthedocs.io). Your issue may be addressed there.
+          required: true
+        - label: Search the [issue tracker](https://github.com/pybind/pybind11/issues) and [Discussions](https:/pybind/pybind11/discussions) to verify that this hasn't already been reported. +1 or comment there if it has.
+          required: true
+        - label: Consider asking first in the [Gitter chat room](https://gitter.im/pybind/Lobby) or in a [Discussion](https:/pybind/pybind11/discussions/new).
+          required: false
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Problem description
+      placeholder: >-
+        Provide a short description, state the expected behavior and what
+        actually happens. Include relevant information like what version of
+        pybind11 you are using, what system you are on, and any useful commands
+        / output.
+    validations:
+      required: true
+
+  - type: textarea
+    id: code
+    attributes:
+      label: Reproducible example code
+      placeholder: >-
+        The code should be minimal, have no external dependencies, isolate the
+        function(s) that cause breakage. Submit matched and complete C++ and
+        Python snippets that can be easily compiled and run to diagnose the
+        issue. If possible, make a PR with a new, failing test to give us a
+        starting point to work on!
+      render: text

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,8 @@
 blank_issues_enabled: false
 contact_links:
+  - name: Ask a question
+    url: https://github.com/pybind/pybind11/discussions/new
+    about: Please ask and answer questions here, or propose new ideas.
   - name: Gitter room
     url: https://gitter.im/pybind/Lobby
     about: A room for discussing pybind11 with an active community

.github/pull_request_template.md

@@ -1,3 +1,7 @@
+<!--
+Title (above): please place [branch_name] at the beginning if you are targeting a branch other than master. *Do not target stable*.
+It is recommended to use conventional commit format, see conventionalcommits.org, but not required.
+-->
 ## Description
 
 <!-- Include relevant issues or PRs here, describe what changed and why -->