Improve sql logging coloration in `ActiveRecord::LogSubscriber`.

- Improves coloring for statements like:

    # Become WHITE
    SELECT * FROM (
        SELECT * FROM mytable FOR UPDATE
    ) ss WHERE col1 = 5;
    LOCK TABLE table_name IN ACCESS EXCLUSIVE MODE;

    # Becomes RED
    ROLLBACK

- Reinstates the coloration of the `payload[:name]`.
  Instead of simple alternating colors, adds meaning:
  - `MAGENTA` for `"SQL"` or `blank?` payload names
  - `CYAN` for Model Load/Exists

- Introduces specs for sql coloration.
- Introduces specs for payload name coloration.

GH#20885

1 files changed, 21 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/log_subscriber.rb b/activerecord/lib/active_record/log_subscriber.rb
index 4d597a0ab1..9e3f1bfb9e 100644
--- a/activerecord/lib/active_record/log_subscriber.rb
+++ b/activerecord/lib/active_record/log_subscriber.rb
@@ -47,7 +47,11 @@ module ActiveRecord
         binds = "  " + payload[:binds].map { |attr| render_bind(attr) }.inspect
       end
 
-      name = color(name, nil, true)
+      if payload[:name].blank? || payload[:name] == "SQL" # SQL vs Model Load/Exists
+        name = color(name, MAGENTA, true)
+      else
+        name = color(name, CYAN, true)
+      end
       sql  = color(sql, sql_color(sql), true)
 
       debug "  #{name}  #{sql}#{binds}"
@@ -55,12 +59,22 @@ module ActiveRecord
 
     def sql_color(sql)
       case sql
-        when /\s*\Ainsert/i      then GREEN
-        when /\s*\Aselect/i      then BLUE
-        when /\s*\Aupdate/i      then YELLOW
-        when /\s*\Adelete/i      then RED
-        when /transaction\s*\Z/i then CYAN
-        else MAGENTA
+        when /\A\s*rollback/mi then
+          RED
+        when /\s*.*?select .*for update/mi, /\A\s*lock/mi then
+          WHITE
+        when /\A\s*select/i then
+          BLUE
+        when /\A\s*insert/i then
+          GREEN
+        when /\A\s*update/i then
+          YELLOW
+        when /\A\s*delete/i then
+          RED
+        when /transaction\s*\Z/i then
+          CYAN
+        else
+          MAGENTA
       end
     end