fix: forward single-value query params in awslambda MultiValueQueryStringParameters

[ahmedomosanya]

Summary

valuesToMultiMap in pkg/middlewares/awslambda/aws_lambda.go excluded every
single-value query parameter (len(value) == 1), so MultiValueQueryStringParameters
was only ever populated with multi-value keys. Because the receiver
(aws-lambda-go-api-proxy core/request.go) reads MultiValueQueryStringParameters
exclusively once it is non-empty, any request with ≥1 multi-value parameter
silently dropped all single-value parameters before they reached the Lambda.

This forwards single-value params as 1-element slices as well, so every query key
is present — matching real AWS API Gateway semantics.

Change

// pkg/middlewares/awslambda/aws_lambda.go — valuesToMultiMap
- if !valid || len(value) == 1 {
+ if !valid {
     continue
 }

Test

• Updated Test_AWSLambdaMiddleware_InvokeBasic (pkg/middlewares/awslambda/aws_lambda_test.go):
  MultiValueQueryStringParameters now expects the single-value keys
  ({"a":{"1"}, "b":{"2"}, "c":{"3","4"}, "d[]":{"5","6"}}) rather than only the
  multi-value ones.
• Added an assertion that every query key in the input appears in the forwarded output.
• go test ./pkg/middlewares/awslambda/... green.

Note

Consumers that pin a built image of this fork will need to rebuild and redeploy to
pick up the change.

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[Copilot]

Pull request overview

Fixes AWS Lambda query forwarding so multi-value parameters no longer cause single-value parameters to be dropped.

Changes:

• Includes all valid query parameters in the multi-value map.
• Updates regression coverage for mixed single- and multi-value queries.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pkg/middlewares/awslambda/aws_lambda.go	Forwards single-value query parameters as one-element slices.
pkg/middlewares/awslambda/aws_lambda_test.go	Verifies all query keys reach the Lambda request.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Suppressed comments (1)

pkg/middlewares/awslambda/aws_lambda.go:442

• valuesToStrings can return (emptySlice, true) when val is a slice but all elements are filtered out as invalid. With the new condition, valuesToMultiMap will now include those keys with an empty slice, which is typically not a meaningful forwarded query parameter and can change behavior downstream. Consider also skipping when len(value) == 0 (or updating valuesToStrings to return valid=false when no elements survive conversion) so only keys with at least one forwarded value are included.

	values := map[string][]string{}
	for name, val := range i {
		value, valid := valuesToStrings(val)
		if !valid {
			continue
		}

[bramwelt]

Waiting on GitHub actions to come back online so i can trigger the build and see tests pass before merging this in and getting it deployed.

[bramwelt]

Closing and re-opening to trigger builds