[exporter/prometheusremotewriteexporter] Fix a go panic

[falken]

Description: Protect against a Go Panic when the bucket count collection is empty (observed with histograms coming from Micrometer 1.9.1

Fixes #12168 #12168

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• :white_check_mark: login: falken / name: Steven Nelson (29f4688b278229f72cfd46b17d8b366b525521dd)

[falken]

Thanks for the fix! Please add a changelog entry https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#changelog

Added, hopefully correctly

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• :white_check_mark: login: falken / name: Steven Nelson (ac91e26958ae7e91fbf1d250158633f8e7bd389d)

[falken]

Okay, @MovieStoreGuy I have added a test, and verified that the fix works, however I can't figure out what's wrong with the assertion.

I get:

helper_test.go:668:
            Error Trace:    /mnt/c/bench/dev/falken/opentelemetry-collector-contrib/pkg/translator/prometheusremotewrite/helper_test.go:668
            Error:          Not equal:
                            expected: map[string]*prompb.TimeSeries{"Histogram-__name__-foo_valid_Histogram_bucket-le-+Inf":(*prompb.TimeSeries)(0xc00028ea80), "Histogram-__name__-foo_valid_Histogram_count":(*prompb.TimeSeries)(0xc00028eaf0), "Histogram-__name__-foo_valid_Histogram_sum":(*prompb.TimeSeries)(0xc00028eb60)}
                            actual  : map[string]*prompb.TimeSeries{"Histogram-__name__-foo_valid_Histogram_bucket-le-+Inf":(*prompb.TimeSeries)(0xc00028ecb0), "Histogram-__name__-foo_valid_Histogram_count":(*prompb.TimeSeries)(0xc00028ec40), "Histogram-__name__-foo_valid_Histogram_sum":(*prompb.TimeSeries)(0xc00028ebd0)}

                            Diff:
            Test:           Test_addSingleHistogramDataPoint/histogram_without_buckets

--- FAIL: Test_addSingleHistogramDataPoint (0.00s) --- FAIL: Test_addSingleHistogramDataPoint/histogram_without_buckets (0.00s)

[MovieStoreGuy]

I think you want to use assert.EqualValues instead of assert.Exactly since I suspect it is trying to enforce the same pointer address.

[falken]

I think you want to use assert.EqualValues instead of assert.Exactly since I suspect it is trying to enforce the same pointer address.

Both Exactly and EqualValues eventually use reflect.DeepEquals, which apparently returns false for the two maps.

[falken]

@MovieStoreGuy Found the problem. Because the +Inf bucket has a value of NaN I can't compare them because NaN == NaN is false. I made the test explicitly test this case which should work.

[MovieStoreGuy]

@MovieStoreGuy Found the problem. Because the +Inf bucket has a value of NaN I can't compare them because NaN == NaN is false. I made the test explicitly test this case which should work.

I am glad you saw that because I did not.

Thank you for taking the time to fix this.

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This PR was marked stale due to lack of activity. It will be closed in 14 days.

[falken]

Apparently this is moot @Aneurysm9 @MovieStoreGuy since PR #12854

[github-actions[bot]]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[github-actions[bot]]

Closed as inactive. Feel free to reopen if this PR is still being worked on.