* Make json require string and pass around metadata
The json deserializer was accepting any inputs by coercing non-strings
into strings. As an example, if the input was `[1, 2]` the coercion
would turn into `[12]` and deserialize as a list containing number
twelve instead of a list of two numbers, one and two. This could lead
to silent data corruption.
Aside from that pipeline metadata wasn't passed aroud.
This commit fixes the type issue by adding a strict conversion
function that errors if the input type is not a string or external
stream. It then uses this function instead of the original
`collect_string()`. In addition, this function returns the pipeline
metadata so it can be passed along.
* Make other formats require string
The problem with json coercing non-string types to string was present in
all other text formats. This reuses the `collect_string_strict` function
to fix them.
* `IntoPipelineData` cleanup
The method `into_pipeline_data_with_metadata` can now be conveniently
used.
d9d6cea5a9