Re-evaluate performances for []*Struct over []Struct

Issue by marcoguerri
Wednesday Feb 05, 2020 at 12:48 GMT
Originally opened as https://github.com/facebookincubator/contest/issues/21

Using []Struct is in most cases probably desirable, but in some cases []*Struct might make sense (e.g. Targets). We should re-evaluate these cases. Here is where we use []*, excluding Targets:

pkg/test/fetcher.go:16: Fetch(interface{}) (string, []*TestStepDescriptor, error)
pkg/job/reporter.go:20: Report(cancel <-chan struct{}, parameters interface{}, results []*test.TestResult, ev testevent.Fetcher) (bool, interface{}, error)
pkg/job/job.go:27:      TestDescriptors []*test.TestDescriptor
pkg/job/job.go:63:      Tests       []*test.Test
pkg/runner/job_runner.go:49:            testResults []*test.TestResult
pkg/jobmanager/jobmanager.go:88:        tests := make([]*test.Test, 0, len(jd.TestDescriptors))
plugins/testfetchers/uri/uri.go:86:func (tf *URI) Fetch(params interface{}) (string, []*test.TestStepDescriptor, error) {
plugins/testfetchers/uri/uri.go:117:            Steps []*test.TestStepDescriptor
plugins/testfetchers/literal/literal.go:29:     Steps    []*test.TestStepDescriptor
plugins/testfetchers/literal/literal.go:54:func (tf *Literal) Fetch(params interface{}) (string, []*test.TestStepDescriptor, error) 

Start by reading the listed usages in pkg/test/fetcher.go, pkg/job/reporter.go, pkg/job/job.go, pkg/runner/job_runner.go, pkg/jobmanager/jobmanager.go, and the URI and literal test fetchers. Compare the []Struct and []*Struct cases, including Targets, and evaluate each representation consistently. Done means every listed case has been re-evaluated and any justified changes are applied across the affected files.