practical migrating guide to crystal-0.20.4

0.md

• https://github.com/crystal-lang/crystal/blob/0.20.4/CHANGELOG.md

1.std.md

Restrict argument types having a default value (#3834)

• crystal-lang/crystal#3834

-    def info(section : String = nil)
+    def info(section : String? = nil)

to_json (aka. missing json_object)

--- a/src/jq/mapping.cr
+++ b/src/jq/mapping.cr
@@ -75,12 +75,12 @@ class Jq
       {% end %}
     end

-    def to_json(io : IO)
-      io.json_object do |json|
+    def to_json(json : JSON::Builder)
+      json.object do
         {% for key, tuple in properties %}
           _{{key.id}} = @{{key.id}}
           json.field({{key.id.stringify}}) do
-            _{{key.id}}.to_json(io)
+            _{{key.id}}.to_json(json)
           end
         {% end %}
       end

OptionParser

• old: OptionParser#parse(Array(String)) : Array(String)
• new: OptionParser#parse(Array(String)) : Nil

x.github-maiha.md

status

• app.cr
• comment-spec.cr
• core-ext.cr
• crc16.cr
• crt.cr
• dstat-redis.cr
• grafana-redis.cr
• hq.cr
• jq.cr
• kafka.cr
• memoized.cr
• opts.cr
• pcap.cr
• rcm.cr
• redis-cluster.cr
• redis-tsv.cr
• rocksdb.cr
• shard.cr
• toml-config.cr
• traildb.cr
• try.c