Add Vale pre-commit hook

CHANGELOG.md

@@ -3,6 +3,8 @@
 ## master (unreleased)
 
 * Add `--disable-pending-cops` as default flag to `RuboCop` pre-commit hook to ignore non-existent cops. Requires RuboCop `0.82.0` or newer.
+* Add "ad-hoc" line-aware command hooks.
+* Add `Vale` pre-commit hook to check spelling and style in text and source files.
 
 ## 0.58.0
 

README.md

@@ -15,7 +15,8 @@
 In addition to supporting a wide variety of hooks that can be used across
 multiple repositories, you can also define hooks specific to a repository which
 are stored in source control. You can also easily
-[add your existing hook scripts](#adding-existing-git-hooks) without writing
+[add your existing hook scripts](#adding-existing-git-hooks) or
+[use some of your existing line-oriented analysis tools](#adding-existing-line-aware-commands) without writing
 any Ruby code.
 
 * [Requirements](#requirements)
@@ -41,6 +42,7 @@ any Ruby code.
   * [PreRebase](#prerebase)
 * [Repo-Specific Hooks](#repo-specific-hooks)
   * [Adding Existing Git Hooks](#adding-existing-git-hooks)
+  * [Adding Existing Line-Aware Commands](#adding-existing-line-aware-commands)
 * [Security](#security)
 * [Contributing](#contributing)
 * [Community](#community)
@@ -240,6 +242,7 @@ Option                                  | Description
 `install_command`                       | Command the user can run to install the `required_executable` (or alternately the specified `required_libraries`). This is intended for documentation purposes, as Overcommit does not install software on your behalf since there are too many edge cases where such behavior would result in incorrectly configured installations (e.g. installing a Python package in the global package space instead of in a virtual environment).
 `skip_file_checkout`                    | Whether to skip this hook for file checkouts (e.g. `git checkout some-ref -- file`). Only applicable to `PostCheckout` hooks.
 `skip_if`                               | Array of arguments to be executed to determine whether or not the hook should run. For example, setting this to a value of `['bash', '-c', '! which my-executable']` would allow you to skip running this hook if `my-executable` was not in the bin path.
+[...]`message_`[...]                    | *[Line-aware command hooks](#adding-existing-line-aware-commands) only.*
 
 In addition to the built-in configuration options, each hook can expose its
 own unique configuration options. The `AuthorEmail` hook, for example, allows
@@ -564,6 +567,7 @@ issue](https://github.com/sds/overcommit/issues/238) for more details.
 * [TrailingWhitespace](lib/overcommit/hook/pre_commit/trailing_whitespace.rb)
 * [TravisLint](lib/overcommit/hook/pre_commit/travis_lint.rb)
 * [TsLint](lib/overcommit/hook/pre_commit/ts_lint.rb)
+* Vale
 * [Vint](lib/overcommit/hook/pre_commit/vint.rb)
 * [W3cCss](lib/overcommit/hook/pre_commit/w3c_css.rb)
 * [W3cHtml](lib/overcommit/hook/pre_commit/w3c_html.rb)
@@ -671,6 +675,70 @@ of hook, see the [git-hooks documentation][GHD].
 
 [GHD]: https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks
 
+### Adding Existing Line-Aware Commands
+
+Or in other words "low-code error format support."
+
+If you use tools that analyze files and report their findings line-by-line,
+and that Overcommit does not yet support, you may be able to integrate them
+with Overcommit without writing any Ruby code in a similar way as
+[for existing Git hooks](#adding-existing-git-hooks).
+
+These special line-aware command hooks behave and are configured the same way
+as the Git ones, except only file arguments get passed to them.
+Also to enable them and for optimal use, one must configure them as explained
+below, so that, using the command output:
+- differentiating between warnings and errors becomes possible
+- modified lines can be detected and acted upon as defined by
+  the `problem_on_unmodified_line`, `requires_files`, `include` and `exclude`
+  [hook options](#hook-options)
+
+**Warning**: Only the command's standard output stream is considered for now,
+*not* its standard error stream.
+
+To differentiate between warning and error messages,
+the `warning_message_type_pattern` option may be specified:
+the `type` field of the `message_pattern` regexp below must then include
+the `warning_message_type_pattern` option's text.
+
+The `message_pattern` option specifies the format of the command's messages.
+It is mandatory, must be a [(Ruby) regexp][RubyRE], and must define at least
+a `file` [named capture group][RubyRENCG].
+The only other allowed ones are `line` and `type`, which when specified
+enable detection of modified lines and warnings respectively.
+
+**Tip**: The following value for this option is often adequate:
+```ruby
+/^(?<file>(?:\w:)?[^:]+):(?<line>\d+):[^ ]* (?<type>[^ ]+)/
+```
+It generalizes the quasi-standard [GNU/Emacs-style error format][GNUEerrf],
+adding the most frequently used warning syntax to it.
+
+For example:
+
+```yaml
+PreCommit:
+  CustomScript:
+    enabled: true
+    command: './bin/custom-script'
+    message_pattern: !ruby/regexp /^(?<file>[^:]+):(?<line>[0-9]+):(?<type>[^ ]+)/
+    warning_message_type_pattern: warning
+```
+
+**Tip**: To get the syntax of the regexps right, a Ruby interpreter like `irb`
+can help:
+
+```ruby
+require('yaml'); puts YAML.dump(/MY-REGEXP/)
+```
+
+Then copy the output line text as the YAML option's value, thereby
+omitting the `---` prefix.
+
+[RubyRE]: https://ruby-doc.org/core-2.4.1/Regexp.html
+[RubyRENCG]: https://ruby-doc.org/core-2.4.1/Regexp.html#class-Regexp-label-Capturing
+[GNUEerrf]: https://www.gnu.org/prep/standards/standards.html#Errors
+
 ## Security
 
 While Overcommit can make managing Git hooks easier and more convenient,

config/default.yml

@@ -842,6 +842,58 @@ PreCommit:
     install_command: 'gem install travis'
     include: '.travis.yml'
 
+  Vale:
+    enabled: false
+    command: "vale"
+    message_pattern: !ruby/regexp /^(?<file>[^:]+):(?<line>[0-9]+):/
+    flags:
+      - '--output=line'
+    include:
+      # All known extensions for all supported formats are included
+      # (see https://docs.errata.ai/vale/scoping#formats), even
+      # the non-built-in ones that require additional software and/or
+      # configuration: they can be disabled easily using 'exclude':
+      - '**/*.adoc'
+      - '**/*.bsh'
+      - '**/*.c'
+      - '**/*.cc'
+      - '**/*.cpp'
+      - '**/*.cs'
+      - '**/*.css'
+      - '**/*.csx'
+      - '**/*.cxx'
+      - '**/*.dita'
+      - '**/*.java'
+      - '**/*.js'
+      - '**/*.go'
+      - '**/*.h'
+      - '**/*.hpp'
+      - '**/*.hs'
+      - '**/*.html'
+      - '**/*.less'
+      - '**/*.lua'
+      - '**/*.md'
+      - '**/*.php'
+      - '**/*.pl'
+      - '**/*.pm'
+      - '**/*.pod'
+      - '**/*.py'
+      - '**/*.py3'
+      - '**/*.pyi'
+      - '**/*.pyw'
+      - '**/*.R'
+      - '**/*.r'
+      - '**/*.rb'
+      - '**/*.rpy'
+      - '**/*.rst'
+      - '**/*.sass'
+      - '**/*.sbt'
+      - '**/*.scala'
+      - '**/*.swift'
+      - '**/*.txt'
+      - '**/*.xhtml'
+      - '**/*.xml'
+
   Vint:
     enabled: false
     description: 'Analyze with Vint'

lib/overcommit/hook_loader/base.rb

@@ -22,6 +22,40 @@ def load_hooks
 
     private
 
+    def is_hook_line_aware(hook_config)
+      hook_config['message_pattern']
+    end
+
+    def create_line_aware_command_hook_class(hook_base) # rubocop:disable Metrics/MethodLength
+      Class.new(hook_base) do
+        def line_aware_config
+          {
+            message_pattern: @config['message_pattern'],
+            warning_message_type_pattern: @config['warning_message_type_pattern']
+          }
+        end
+
+        def run
+          result = execute(command, args: applicable_files)
+
+          return :pass if result.success?
+
+          extract_messages(line_aware_config, result)
+        end
+
+        def extract_messages(line_aware_config, result)
+          warning_message_type_pattern = line_aware_config[:warning_message_type_pattern]
+          Overcommit::Utils::MessagesUtils.extract_messages(
+            result.stdout.split("\n"),
+            line_aware_config[:message_pattern],
+            Overcommit::Utils::MessagesUtils.create_type_categorizer(
+              warning_message_type_pattern
+            )
+          )
+        end
+      end
+    end
+
     attr_reader :log
 
     # Load and return a {Hook} from a CamelCase hook name.

lib/overcommit/hook_loader/plugin_hook_loader.rb

@@ -74,23 +74,37 @@ def check_for_modified_plugins
       raise Overcommit::Exceptions::InvalidHookSignature
     end
 
-    def create_ad_hoc_hook(hook_name)
-      hook_module = Overcommit::Hook.const_get(@context.hook_class_name)
-      hook_base = hook_module.const_get('Base')
-
+    def create_git_hook_class(hook_base)
       # Implement a simple class that executes the command and returns pass/fail
       # based on the exit status
-      hook_class = Class.new(hook_base) do
+      Class.new(hook_base) do
         def run
           result = @context.execute_hook(command)
-
           if result.success?
             :pass
           else
             [:fail, result.stdout + result.stderr]
           end
         end
       end
+    end
+
+    def create_ad_hoc_hook(hook_name)
+      hook_module = Overcommit::Hook.const_get(@context.hook_class_name)
+      hook_base = hook_module.const_get('Base')
+
+      hook_config = @config.for_hook(hook_name, @context.hook_class_name)
+      hook_class =
+        if is_hook_line_aware(hook_config)
+          create_line_aware_command_hook_class(hook_base)
+        else
+          create_git_hook_class(hook_base)
+        end
+
+      # Only to avoid warnings in unit tests...:
+      if hook_module.const_defined?(hook_name)
+        return hook_module.const_get(hook_name).new(@config, @context)
+      end
 
       hook_module.const_set(hook_name, hook_class).new(@config, @context)
     rescue LoadError, NameError => e

lib/overcommit/utils/messages_utils.rb

@@ -37,6 +37,14 @@ def extract_messages(output_messages, regex, type_categorizer = nil)
         end
       end
 
+      def create_type_categorizer(warning_pattern)
+        return nil if warning_pattern.nil?
+
+        lambda do |type|
+          type.include?(warning_pattern) ? :warning : :error
+        end
+      end
+
       private
 
       def extract_file(match, message)