YamlPropertiesFactoryBean incorrect flatten nested map to properties

[remeio]

To fix issue #27020.

For the method org.springframework.beans.factory.config.YamlProcessor#getFlattenedMap before this PR:

• When the key is start with [, will return path + key as map key.
• Otherwise, will return path + '.' + key as map key.

if (key.startsWith("[")) { key = path + key; } else { key = path + '.' + key; }

For the method org.springframework.beans.factory.config.YamlProcessor#getFlattenedMap after this PR:

• When the key is start with [ or end with ], will return path + '[' + key + ']' as map key.
• Otherwise, will return path + '.' + key as map key.
• And when the key is indexed key at Collection like [0], will return path + key as map key.

For the method org.springframework.beans.factory.config.YamlProcessor#asMap after this PR:
Change result.put("[" + key.toString() + "]", value); to result.put(key.toString(), value); on asMap.

And the test case you can see:

root: webservices: "[domain.test:8080]": - username: foo password: bar # Before this PR: # root.webservices[domain.test:8080][0].username=foo # root.webservices[domain.test:8080][0].password=bar # After this PR: # root.webservices[[domain.test:8080]][0].username=foo # root.webservices[[domain.test:8080]][0].password=bar indexed: "[0]": foo "[1]": bar indexed2: - "[a]": foo "[b]": bar # Before this PR: # indexed[0]=foo # indexed[1]=bar # indexed2[0][a]=foo # indexed2[0][b]=bar # After this PR: # indexed[[0]]=foo # indexed[[1]]=bar # indexed2[0][[a]]=foo # indexed2[0][[b]]=bar only-left-bracket: "[/key1/": foo only-right-bracket: "/key1/]": foo special-bracket: "][/key1/][": foo # Before this PR: # only-left-bracket[/key1/=foo # only-right-bracket./key1/]=foo # special-bracket.][/key1/][=foo # After this PR: # only-left-bracket[[/key1/]=foo # only-right-bracket[/key1/]]=foo # special-bracket.][/key1/][=foo number-key: 1: foo # Before this PR: # number-key[1]=bar # After this PR: # number-key.1=foo

By the way, org.springframework.beans.factory.config.YamlMapFactoryBean#getObject result is:

# Before this PR & After this PR: # root={webservices={[domain.test:8080]=[{username=foo, password=bar}]}} # indexed={[0]=foo, [1]=bar} # indexed2=[{[a]=foo, [b]=bar}] # only-left-bracket={[/key1/=foo} # only-right-bracket={/key1/]=foo} # special-bracket={][/key1/][=foo} # Before this PR: # number-key={[1]=foo} # After this PR: # number-key={1=foo} 

[remeio]

This PR just is a try, I submit the test case for []. It's important to explain what result is correct for this test case. Maybe you can fill it with:

root: webservices: "[domain.test:8080]": - username: foo password: bar # properties should be? # map should be? indexed: "[0]": foo "[1]": bar indexed2: - "[a]": foo "[b]": bar # properties should be? # map should be? only-left-bracket: "[/key1/": foo only-right-bracket: "/key1/]": foo special-bracket: "][/key1/][": foo # properties should be? # map should be? number-key: 1: foo # properties should be? # map should be?

By the way, If We want to use @ConfigurationProperties on Spring Boot, we need to config yaml file with following the document Binding Maps. We can see:

When binding to Map properties you may need to use a special bracket notation so that the original key value is preserved.