A problem with a plan's options or source, returned by ImagePipe.URL.validate/1, ImagePipe.URL.url/3, and ImagePipe.URL.url_with_issues/3, and by ImagePipe.validate/2 and ImagePipe.run/4 in image_pipe.

%ImagePipe.Plan.Spec.Issue{
  reason: :inert_option,
  locations: [{:group, 0, :fit}],
  detail: {:requires, :resize},
  severity: :warning
}

severity is :error or :warning. An error fails the request. A warning marks an option the request ignores because it has no effect, or a builder mistake with one clear meaning, which the builder repairs. The checks return warnings alone as {:ok, warnings}, and list them after the errors in {:error, issues}. They report only options the plan sets itself, not ones that a preset or the request defaults supply.

locations lists the options involved. {:group, index, key} is an option of the group at the zero-based index, and {:request, key} is a request-wide option. Keys are builder option names, and resize: options appear under their own names, such as :width and :fit.

reason is one of:

• :unknown_option - the name isn't a builder option.
• :invalid_value - the builder rejects the option's value. detail is the builder's message, such as "invalid value for :fit option: expected one of [:contain, :cover, :stretch, :auto], got: :fill".
• :repeated_option - a warning: the option was given twice in one builder call, or a key was repeated inside its list value, and the URL uses the last value.
• :empty_group - a warning: an ImagePipe.URL.group/2 call has no options, or only an empty presets: or resize: list, and adds no group. locations is empty.
• :redundant_unset - a warning: [:unset] alone or a repeated leading :unset in format_qualities: or an encoder option such as jpeg_options:. The builder writes a single :unset.
• :invalid_source, :too_many_options - returned only by ImagePipe.URL.url_with_issues/3, for what ImagePipe.URL.url/3 returns as {:error, :invalid_source} and {:error, :too_many_options}. locations is empty.
• :inert_option - a warning: the option has no effect, such as fit without a width or height, or jpeg_options with format: :webp, so the request ignores it.
• :mutually_exclusive_options - the options can't be combined, such as extend and extend_ratio.
• :invalid_offset - a pixel offset is too large to multiply by the group's dpr.
• :unknown_preset - a named preset isn't defined.
• :pipeline_preset_with_group_options, :pipeline_preset_with_preset, :multiple_pipeline_presets - a preset that defines several groups is combined with options or presets it can't be combined with.
• :unknown_watermark, :watermark_source_disabled - the plan names a watermark the server doesn't define, or uses watermark_source where the server doesn't allow it. ImagePipe.validate/2 and ImagePipe.run/4 return both. ImagePipe.URL.validate/1 and ImagePipe.URL.url/3 return :unknown_watermark when the URL configuration's :validate_against lists the watermark names, and :watermark_source_disabled when it sets request_watermarks: false.

detail describes the failed constraint, such as {:requires, :resize} or %{preset: "card"}, holds the builder's message for :invalid_value, or is nil.