feat: add pre-commit framework

.pre-commit-config.yaml

+---
+default_stages: [commit, push]
+default_language_version:
+  # force all unspecified Python hooks to run python3
+  python: python3
+minimum_pre_commit_version: "1.20.0"
+repos:
+  - repo: meta
+    hooks:
+      - id: identity
+      - id: check-hooks-apply
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v3.4.0
+    hooks:
+      - id: check-added-large-files
+      - id: check-case-conflict
+      - id: check-merge-conflict
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: fix-byte-order-marker
+      - id: mixed-line-ending
+      - id: trailing-whitespace
+  # - repo: git://github.com/Lucas-C/pre-commit-hooks
+  #  rev: v1.1.9
+  #  hooks:
+  #    - id: forbid-tabs
+  #    - id: remove-tabs
+  - repo: https://github.com/igorshubovych/markdownlint-cli
+    rev: v0.26.0
+    hooks:
+      - id: markdownlint
+        name: Run markdownlint
+  - repo: https://github.com/adrienverge/yamllint
+    rev: v1.26.0
+    hooks:
+      - id: yamllint
+        name: Check YAML files with yamllint
+        entry: yamllint --strict .
+        types: [yaml]

CONTRIBUTING.md

@@ -18,6 +18,15 @@ things in mind before submitting your pull request:
 * Use mrbgem to provide non ISO features (classes, modules and methods) unless
   you have a special reason to implement them in the core
 
+## Pre-commit
+
+A framework for managing and maintaining multi-language pre-commit hooks.
+Pre-commit can be [installed](https://pre-commit.com/#installation) with `pip`, `curl`, `brew` or `conda`.
+You need to first install pre-commit and then install the pre-commit hooks with `pre-commit install`.
+Now pre-commit will run automatically on git commit!
+It's usually a good idea to run the hooks against all the files when adding new hooks (usually pre-commit will only run on the changed files during git hooks).
+Use `pre-commit run --all-files` to check all files.
+
 ## Coding conventions
 
 How to style your C and Ruby code which you want to submit.

LEGAL

@@ -3,4 +3,3 @@ LEGAL NOTICE INFORMATION
 
 All the files in this distribution are covered under the MIT license
 (see the file LICENSE) except some files mentioned below:
-

LICENSE

@@ -17,4 +17,3 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.
-

NEWS

@@ -9,5 +9,3 @@ with all sufficient information, see the ChangeLog file.
 
 
 ** Information about first release v1.0.0
-
-

mrbgems/mruby-bin-debugger/tools/mrdb/mrdberror.h

@@ -17,4 +17,3 @@
 #define MRB_DEBUG_BREAK_NO_OVER        (-15)
 
 #endif
-

mrbgems/mruby-compiler/core/lex.def

@@ -205,4 +205,3 @@ mrb_reserved_word (register const char *str, register size_t len)
   return 0;
 }
 #line 52 "mrbgems/mruby-compiler/core/keywords"
-

mrbgems/mruby-sleep/example/sleep.rb

 sleep(10)
 usleep(10000)
-

mrbgems/mruby-toplevel-ext/test/toplevel.rb

@@ -21,4 +21,3 @@ assert('Toplevel#include') do
   assert_equal :foo, method_foo
   assert_equal :bar2, CONST_BAR
 end
-

test/t/basicobject.rb

@@ -8,4 +8,3 @@ end
 assert('BasicObject superclass') do
   assert_nil(BasicObject.superclass)
 end
-

test/t/iterations.rb

@@ -58,4 +58,4 @@ assert('next expression', '11.5.2.4.4') do
     end
     all
   end
-end
\ No newline at end of file
+end

test/t/object.rb

@@ -8,4 +8,3 @@ end
 assert('Object superclass', '15.2.1.2') do
   assert_equal BasicObject, Object.superclass
 end
-