Remove support to set map and array to attribute value

[bogdandrutu]

This makes things consistent with other generated code where we do not allow
to set non immutable fields.

User can get access to the Map/Array and change that in-place.

Signed-off-by: Bogdan Drutu [email protected]

[codecov]

Codecov Report

Merging #2039 into master will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2039      +/-   ##
==========================================
+ Coverage   91.94%   91.96%   +0.02%     
==========================================
  Files         282      282              
  Lines       16804    16786      -18     
==========================================
- Hits        15450    15438      -12     
+ Misses        928      926       -2     
+ Partials      426      422       -4     

Impacted Files	Coverage Δ
consumer/pdata/common.go	98.31% <100.00%> (+1.80%)	⬆️

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[tigrannajaryan]

This makes things consistent with other generated code where we do not allow
to set non immutable fields.

I don't understand why we need this change. The current code looks consistent to me. We do allow setting fields to a value of any supported type, including arrays and maps. Why shouldn't we?

[bogdandrutu]

I don't understand why we need this change. The current code looks consistent to me. We do allow setting fields to a value of any supported type, including arrays and maps. Why shouldn't we?

The maps and arrays are not immutable and requires deep copy. We want users to get the MapValue() -> AttributeMap and change that.

A similar example is in Resource https://github.com/open-telemetry/opentelemetry-collector/blob/master/consumer/pdata/generated_resource.go#L65 where we give access to the AttributeMap that can be mutated, similar in Span for attributes, etc.

We do let user "set" only immutable fields like string, but things that are mutable we give access to the mutable field which gives access to set immutable fields.

Another prof of misuse is the file that I changed exporter/loggingexporter/logging_exporter_test.go, see how I was able to reduce some unnecessary allocations (point taken that it is in test, but will happen in code as well).

[tigrannajaryan]

Discussed offline, not needed now, we can add later if needed.