bug: Ingress annotations: comma-separated values are not trimmed, causing invalid IP parsing when spaces are present

[vdegans]

Summary

When parsing comma-separated annotation values in the APISIX Ingress Controller, the implementation performs a simple strings.Split(value, ",") without trimming whitespace from the resulting elements. This causes leading or trailing spaces to be preserved in values following a comma.

As a result, annotations that define multiple IP addresses fail if a space is included after the comma.

Example

If an annotation is defined as:
127.0.0.1, 0.0.0.0
After splitting on , the resulting values are:
["127.0.0.1", " 0.0.0.0"]
The second value contains a leading space, which causes IP validation to fail.

Why This Is Problematic

1. A space character is never valid in an IP address.
2. Including a space after a comma is extremely common and idiomatic in programming and configuration formats.
3. Users do not typically expect comma-separated configuration values to require manual whitespace management.
4. This creates unnecessary fragility in configuration and leads to avoidable validation errors.

Related snippet

apisix-ingress-controller/internal/adc/translator/annotations/types.go

Line 134 in c48e9b3

return strings.Split(value, ",")

Proposed Resolution

Either:

1. Trim whitespace on each split element (preferred)
   or
2. Explicitly document that whitespace is not allowed in comma-separated annotation values.

Potential problems

This splitting helper appears to be shared across annotations, so trimming would change parsing behavior globally.

[philipsens]

The controller fails to apply this with ADC. When I tried this, it seems like all other ingresses don't get updated either, which causes a pause in synchronizations across all ingresses that use that gateway as ingressClass.

[Baoyuantop]

The GetStringsAnnotation method, after splitting strings using strings.Split(value, ","), does not call strings.TrimSpace on each element. This results in the splitting result containing leading spaces (" 0.0.0.0") when there are spaces after the comma (e.g., 127.0.0.1, 0.0.0.0). This string with spaces fails validation when passed to APISIX as an IP address.