Remove use of rescue nil.

* `rescue nil` is a really bad pattern to use in our code base.
  We should rescue errors that we expect the code to throw and
  not rescue everything because we're unsure of what errors the
  code would throw. This would reduce the amount of pain we face
  when debugging why something isn't working as expexted. I've
  been bitten countless of times by errors being swallowed as a
  result during debugging sessions.

lib/backup_restore/backuper.rb

@@ -316,8 +316,8 @@ module BackupRestore
 
     def log(message)
       timestamp = Time.now.strftime("%Y-%m-%d %H:%M:%S")
-      puts(message) rescue nil
-      publish_log(message, timestamp) rescue nil
+      puts(message)
+      publish_log(message, timestamp)
       save_log(message, timestamp)
     end
 

lib/backup_restore/restorer.rb

@@ -500,8 +500,8 @@ module BackupRestore
 
     def log(message)
       timestamp = Time.now.strftime("%Y-%m-%d %H:%M:%S")
-      puts(message) rescue nil
-      publish_log(message, timestamp) rescue nil
+      puts(message)
+      publish_log(message, timestamp)
       save_log(message, timestamp)
     end
 

lib/discourse.rb

@@ -128,7 +128,11 @@ module Discourse
     if Rails.env.development?
       plugin_hash = Digest::SHA1.hexdigest(all_plugins.map { |p| p.path }.sort.join('|'))
       hash_file = "#{Rails.root}/tmp/plugin-hash"
-      old_hash = File.read(hash_file) rescue nil
+
+      old_hash = begin
+        File.read(hash_file)
+      rescue Errno::ENOENT
+      end
 
       if old_hash && old_hash != plugin_hash
         puts "WARNING: It looks like your discourse plugins have recently changed."
@@ -236,7 +240,13 @@ module Discourse
   end
 
   def self.route_for(uri)
-    uri = URI(uri) rescue nil unless uri.is_a?(URI)
+    unless uri.is_a?(URI)
+      uri = begin
+        URI(uri)
+      rescue URI::InvalidURIError
+      end
+    end
+
     return unless uri
 
     path = uri.path || ""

lib/email/receiver.rb

@@ -823,7 +823,7 @@ module Email
             end
           end
         ensure
-          tmp.try(:close!) rescue nil
+          tmp&.close!
         end
       end
 

lib/final_destination.rb

@@ -30,20 +30,12 @@ class FinalDestination
 
   def initialize(url, opts = nil)
     @url = url
-    @uri =
-      begin
-        URI(escape_url) if @url
-      rescue URI::InvalidURIError
-      end
+    @uri = uri(escape_url) if @url
 
     @opts = opts || {}
     @force_get_hosts = @opts[:force_get_hosts] || []
     @opts[:max_redirects] ||= 5
-    @opts[:lookup_ip] ||= lambda do |host|
-      begin
-        FinalDestination.lookup_ip(host)
-      end
-    end
+    @opts[:lookup_ip] ||= lambda { |host| FinalDestination.lookup_ip(host) }
     @ignored = [Discourse.base_url_no_prefix] + (@opts[:ignore_redirects] || [])
     @limit = @opts[:max_redirects]
     @status = :ready
@@ -106,9 +98,8 @@ class FinalDestination
 
     if result == :redirect
       old_port = uri.port
-
       location = "#{uri.scheme}://#{uri.host}#{location}" if location[0] == "/"
-      uri = URI(location) rescue nil
+      uri = uri(location)
 
       # https redirect, so just cache that whole new domain is https
       if old_port == 80 && uri&.port == 443 && (URI::HTTPS === uri)
@@ -204,9 +195,8 @@ class FinalDestination
 
     if location
       old_port = @uri.port
-
       location = "#{@uri.scheme}://#{@uri.host}#{location}" if location[0] == "/"
-      @uri = URI(location) rescue nil
+      @uri = uri(location)
       @limit -= 1
 
       # https redirect, so just cache that whole new domain is https
@@ -243,7 +233,8 @@ class FinalDestination
   end
 
   def hostname_matches?(url)
-    @uri && url.present? && @uri.hostname == (URI(url) rescue nil)&.hostname
+    url = uri(url)
+    @uri && url.present? && @uri.hostname == url&.hostname
   end
 
   def is_dest_valid?
@@ -383,4 +374,13 @@ class FinalDestination
     end
   end
 
+  private
+
+  def uri(location)
+    begin
+      URI(location)
+    rescue URI::InvalidURIError, ArgumentError
+    end
+  end
+
 end

lib/import_export/importer.rb

@@ -161,7 +161,10 @@ module ImportExport
     end
 
     def new_category_id(external_category_id)
-      CategoryCustomField.where(name: "import_id", value: "#{external_category_id}#{import_source}").first.category_id rescue nil
+      CategoryCustomField.where(
+        name: "import_id",
+        value: "#{external_category_id}#{import_source}"
+      ).first&.category_id
     end
 
     def import_source

lib/inline_oneboxer.rb

@@ -29,10 +29,12 @@ class InlineOneboxer
       return cached if cached.present?
     end
 
+    return unless url
+
     if route = Discourse.route_for(url)
       if route[:controller] == "topics" &&
         route[:action] == "show" &&
-        topic = (Topic.where(id: route[:topic_id].to_i).first rescue nil)
+        topic = Topic.where(id: route[:topic_id].to_i).first
 
         return onebox_for(url, topic.title, opts) if Guardian.new.can_see?(topic)
       end
@@ -42,7 +44,10 @@ class InlineOneboxer
     domains = SiteSetting.inline_onebox_domains_whitelist&.split('|') unless always_allow
 
     if always_allow || domains
-      uri = URI(url) rescue nil
+      uri = begin
+        URI(url)
+      rescue URI::InvalidURIError
+      end
 
       if uri.present? &&
         uri.hostname.present? &&

lib/site_setting_extension.rb

@@ -339,10 +339,15 @@ module SiteSettingExtension
   end
 
   def get_hostname(url)
-    unless (URI.parse(url).scheme rescue nil).nil?
-      url = "http://#{url}" if URI.parse(url).scheme.nil?
-      url = URI.parse(url).host
+    uri = begin
+      URI.parse(url)
+    rescue URI::InvalidURIError
     end
+
+    unless uri.scheme.nil?
+      url = uri.host
+    end
+
     url
   end
 

lib/socket_server.rb

@@ -16,7 +16,7 @@ class SocketServer
   end
 
   def stop
-    @server&.close rescue nil
+    @server&.close
     FileUtils.rm_f(@socket_path)
     @server = nil
     @blk = nil
@@ -72,7 +72,7 @@ class SocketServer
   rescue => e
     Rails.logger.warn("Failed to handle connection in stats socket #{e}:\n#{e.backtrace.join("\n")}")
   ensure
-    socket&.close rescue nil
+    socket&.close
   end
 
   def get_response(command)

lib/stylesheet/manager.rb

@@ -110,7 +110,11 @@ class Stylesheet::Manager
       if File.exists?(stylesheet_fullpath)
         unless StylesheetCache.where(target: qualified_target, digest: digest).exists?
           begin
-            source_map = File.read(source_map_fullpath) rescue nil
+            source_map = begin
+              File.read(source_map_fullpath)
+            rescue Errno::ENOENT
+            end
+
             StylesheetCache.add(qualified_target, digest, File.read(stylesheet_fullpath), source_map)
           rescue => e
             Rails.logger.warn "Completely unexpected error adding contents of '#{stylesheet_fullpath}' to cache #{e}"

lib/upload_creator.rb

@@ -105,7 +105,7 @@ class UploadCreator
       @upload
     end
   ensure
-    @file.close! rescue nil
+    @file&.close
   end
 
   def extract_image_info!
@@ -149,7 +149,7 @@ class UploadCreator
       @opts[:content_type] = "image/jpeg"
       extract_image_info!
     else
-      jpeg_tempfile.close! rescue nil
+      jpeg_tempfile&.close
     end
   end
 

lib/validators/upload_url_validator.rb

@@ -1,7 +1,11 @@
 class UploadUrlValidator < ActiveModel::EachValidator
   def validate_each(record, attribute, value)
     if value.present?
-      uri = URI.parse(value) rescue nil
+      uri =
+        begin
+          URI.parse(value)
+        rescue URI::InvalidURIError
+        end
 
       unless uri && Upload.exists?(url: value)
         record.errors[attribute] << (options[:message] || I18n.t('errors.messages.invalid'))