TextFormatUtil.writeTimestamp writes a value with a decimal point but the spec specifies an int64

[garthy]

The method here https://github.com/prometheus/client_java/blob/7016bf7c5749e806ef91a918fdb294d394b83a16/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/TextFormatUtil.java#L24C15-L35

static void writeTimestamp(Writer writer, long timestampMs) throws IOException {
    writer.write(Long.toString(timestampMs / 1000L));
    writer.write(".");

Writes a decimal point.

The spec https://prometheus.io/docs/instrumenting/exposition_formats/#text-format-details

specifies the timestamp as an int64

The timestamp is an int64 (milliseconds since epoch, i.e. 1970-01-01 00:00:00 UTC, excluding leap seconds), represented as required by Go's [ParseInt()](https://golang.org/pkg/strconv/#ParseInt) function.

This causes Prometheus/promtool to error on metrics with a timestamp

error while linting: text format parsing error in line 17: expected integer as timestamp, got "1739889638.000"

[zeitlinger]

@fstab do you have an idea why we might have added the decimal point?

[garthy]

Hi any idea when this is getting in a Release? Thanks

[zeitlinger]

It's here: https://github.com/prometheus/client_java/releases/tag/v1.3.7