HtmlUnitRequestBuilder doesn't handle query parameters without equals sign [SPR-13524]

[spring-projects-issues]

Christopher Smith opened SPR-13524 and commented

Blank request parameters are used occasionally to conditionally turn on messages inside templates. For example, Spring Security uses /login?error to indicate that a username/password pair was incorrect. However, HtmlUnitRequestBuilder currently attempts to decode null values for query parameters which results in a NullPointerException. See the following stack trace for details.

Caused by: java.lang.NullPointerException
	at java.net.URLDecoder.decode(URLDecoder.java:136)
	at org.springframework.test.web.servlet.htmlunit.HtmlUnitRequestBuilder.params(HtmlUnitRequestBuilder.java:365)
	at org.springframework.test.web.servlet.htmlunit.HtmlUnitRequestBuilder.buildRequest(HtmlUnitRequestBuilder.java:121)
	at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:140)
	at org.springframework.test.web.servlet.htmlunit.MockMvcWebConnection.getResponse(MockMvcWebConnection.java:122)

Adding an equals sign with no content prevents the exception but shouldn't be required, especially since other Spring components generate redirects with this form.

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Affects: 4.2 GA

Issue Links:

• UriComponentsBuilder interprets empty request parameters as null [SPR-13537] #18113 UriComponentsBuilder interprets empty request parameters as null

Referenced from: commits 283fc94, 61a46db

[spring-projects-issues]

Sam Brannen commented

Fixed in GitHub commit 283fc94:

Support null query param values in HtmlUnitRequestBuilder

Prior to this commit, HtmlUnitRequestBuilder would incorrectly attempt
to decode null values for query parameters (i.e., query parameters such
as 'error' in 'http://example.com/login?error') which resulted in a
NullPointerException since URLDecoder.decode() does not support null
values.

This commit fixes this issue by ensuring that HtmlUnitRequestBuilder
only attempts to decode non-null query parameter values.

[spring-projects-issues]

Sam Brannen commented

See also: #18113

[spring-projects-issues]

Sam Brannen commented

Refined in GitHub commit 61a46db:

Treat query param w/o "=" as empty string in HtmlUnitRequestBuilder

Prior to this commit, HtmlUnitRequestBuilder stored empty query parameters declared without an equals sign as null (i.e., query parameters such as error in http://example.com/login?error).

This commit addresses this issue by ensuring that HtmlUnitRequestBuilder treats all empty query parameter values as empty strings. Consequently, query strings such as ?error and ?error= now both result in error being stored as an empty string.