Make slash commands contextual

- Return only slash commands that make sense for the current noteable
- Allow slash commands decription to be dynamic

Other improvements:

- Add permission checks in slash commands definition
- Use IssuesFinder and MergeRequestsFinder
- Use next if instead of a unless block, and use splat operator instead of flatten

Signed-off-by: Rémy Coutable <remy@rymai.me>

1 files changed, 31 insertions, 9 deletions

diff --git a/lib/gitlab/slash_commands/dsl.rb b/lib/gitlab/slash_commands/dsl.rb
index edfe8405876..20e1d071d06 100644
--- a/lib/gitlab/slash_commands/dsl.rb
+++ b/lib/gitlab/slash_commands/dsl.rb
@@ -8,15 +8,25 @@ module Gitlab
       end
 
       module ClassMethods
-        def command_definitions
-          @command_definitions
-        end
+        def command_definitions(opts = {})
+          @command_definitions.map do |cmd_def|
+            next if cmd_def[:cond_lambda] && !cmd_def[:cond_lambda].call(opts)
+
+            cmd_def = cmd_def.dup
 
-        def command_names
-          command_definitions.flat_map do |command_definition|
-            unless command_definition[:noop]
-              [command_definition[:name], command_definition[:aliases]].flatten
+            if cmd_def[:description].present? && cmd_def[:description].respond_to?(:call)
+              cmd_def[:description] = cmd_def[:description].call(opts) rescue ''
             end
+
+            cmd_def
+          end.compact
+        end
+
+        def command_names(opts = {})
+          command_definitions(opts).flat_map do |command_definition|
+            next if command_definition[:noop]
+
+            [command_definition[:name], *command_definition[:aliases]]
           end.compact
         end
 
@@ -35,6 +45,11 @@ module Gitlab
           @noop = noop
         end
 
+        # Allows to define if a lambda to conditionally return an action
+        def condition(cond_lambda)
+          @cond_lambda = cond_lambda
+        end
+
         # Registers a new command which is recognizeable
         # from body of email or comment.
         # Example:
@@ -53,6 +68,10 @@ module Gitlab
           define_method(proxy_method_name, &block)
 
           define_method(command_name) do |*args|
+            unless @cond_lambda.nil? || @cond_lambda.call(project: project, current_user: current_user, noteable: noteable)
+              return
+            end
+
             proxy_method = method(proxy_method_name)
 
             if proxy_method.arity == -1 || proxy_method.arity == args.size
@@ -70,13 +89,16 @@ module Gitlab
             name: command_name,
             aliases: aliases,
             description: @description || '',
-            params: @params || [],
-            noop: @noop || false
+            params: @params || []
           }
+          command_definition[:noop] = @noop unless @noop.nil?
+          command_definition[:cond_lambda] = @cond_lambda unless @cond_lambda.nil?
           @command_definitions << command_definition
 
           @description = nil
           @params = nil
+          @noop = nil
+          @cond_lambda = nil
         end
       end
     end