GitLabForm fails to handle lists of values properly, overriding earlier entries

[Malenczuk]

In version 6.0.0-rc.7, the GitLabForm class has a method withParam(String name, List<T> values, boolean required) for handling lists of values. However, this method overrides the previously added values in the list when adding parameters to formValues. As a result, only the last value from the list is retained.

Problematic Code

for (T value : values) {
    if (value != null) {
        formValues.put(name + "[]", value.toString());
    }
}

In the above code, formValues.put() is used. Since Map does not allow duplicate keys, each new value with the same key (name + "[]") overrides the previous one.

Expected Behavior

The method should allow multiple values for the same parameter (e.g., appending to a list instead of overwriting). This is required for correctly sending form or query parameters like name[]=value1&name[]=value2.

Actual Behavior

Only the last value from the list is added to formValues.

---

Steps to Reproduce

1. Create an instance of GitLabForm.
2. Call withParam("names", Arrays.asList("value1", "value2", "value3")).
3. Retrieve getFormValues() and check the result.

Sample Code:

GitLabForm form = new GitLabForm();
form.withParam("names", Arrays.asList("value1", "value2", "value3"));
System.out.println(form.getFormValues());

Actual Output:

{names[]=value3}

Expected Output:

{names[]=[value1, value2, value3]}

[jmini]

This is very valuable feedback and probably introduced by the change made for this issue: #1067

I will try to look into this, if you know how to fix it, feel free to send a pull-request.

[jmini]

In GitLabApiForm the loop is correct and continue to work.

gitlab4j-api/gitlab4j-api/src/main/java/org/gitlab4j/api/GitLabApiForm.java

Lines 139 to 143 in 28f43e5

	for (T value : values) {
	if (value != null) {
	this.param(name + "[]", value.toString());
	}
	}

Tested with ProjectAccessTokenScript using:

jbang ProjectAccessTokenScript.java CREATE_PROJECT_ACCESS_TOKEN --project *** --tokenName test2 --scope API --scope READ_API --expiresAt 2024-12-25

---

The problem is GitLabForm:

gitlab4j-api/gitlab4j-models/src/main/java/org/gitlab4j/models/GitLabForm.java

Lines 124 to 128 in 28f43e5

	for (T value : values) {
	if (value != null) {
	formValues.put(name + "[]", value.toString());
	}
	}

Because formValues is a Map<String, String> when MultivaluedMap<String, String> was used before.

[jmini]

Can be reproduced with the GroupScript.java script:

jbang GroupScript.java GET_DESCENDANT_GROUPS --group <id> --skip <id1> --skip <id2> -v

Only one of the 2 groups is filtered <id1> and <id2> when two are expected