ci: add support for testing minimum Go version (#165)

This PR relaxes the minimum compiler version to 1.18, as the only new
feature we were using was the standard library `slices` package. This
can be replaced with `x/exp/slices`.

To test the minimum version, I've added a new key/value to
`go-versions.env`. This version is now tested in CI, and can be easily
bumped using `make bump-min-go-version MIN_GO_VERSION=foo`.

Finally, I've updated our documentation to clarify our support policy.

.github/variables/go-versions.env

@@ -1,2 +1,3 @@
 latest=1.22
 penultimate=1.21
+min=1.18

.github/workflows/go-versions.yml

@@ -27,6 +27,9 @@ on:
       penultimate:
         description: 'The second most recent Go version to test'
         value: ${{ jobs.go-versions.outputs.penultimate }}
+      min:
+        description: 'The minimum Go version to test'
+        value: ${{ jobs.go-versions.outputs.min }}
       matrix:
         description: 'All Go versions to test as a matrix'
         value: ${{ jobs.go-versions.outputs.all }}
@@ -46,4 +49,4 @@ jobs:
       - name: Set Go Version Matrices
         id: set-matrix
         run: |
-          echo "all=[\"${{ steps.set-env.outputs.latest }}\",\"${{ steps.set-env.outputs.penultimate }}\"]" >> $GITHUB_OUTPUT
+          echo "all=[\"${{ steps.set-env.outputs.latest }}\",\"${{ steps.set-env.outputs.penultimate }}\",\"${{ steps.set-env.outputs.min }}\"]" >> $GITHUB_OUTPUT

CONTRIBUTING.md

@@ -16,6 +16,19 @@ We encourage pull requests and other contributions from the community. Before su
 
 This project should be built against the lowest supported Go version as described in [README.md](./README.md).
 
+### Bumping the Minimum Go Version
+
+The SDK is tested against three Go versions: the latest, penultimate, and a minimum based on the SDKs usage of Go features.
+
+Whereas the latest and penultimate are updates on a regular cadence to track upstream Go releases, the minimum version
+may be bumped at the discretion of the SDK maintainers to take advantage of new features.
+
+Invoke the following make command, which will update `go.mod`, `ldotel/go.mod`, `testservice/go.mod`, and 
+`.github/variables/go-versions.env` (pass the desired Go version):
+```shell
+make bump-min-go-version MIN_GO_VERSION=1.18
+```
+
 ### Building
 
 To build all modules without running any tests:

Makefile

@@ -1,5 +1,5 @@
 
-GOLANGCI_LINT_VERSION=v1.57.1
+GOLANGCI_LINT_VERSION=v1.60.1
 
 LINTER=./bin/golangci-lint
 LINTER_VERSION_FILE=./bin/.golangci-lint-version-$(GOLANGCI_LINT_VERSION)
@@ -33,6 +33,12 @@ all: $(ALL_BUILD_TARGETS)
 
 test: $(ALL_TEST_TARGETS)
 
+bump-min-go-version:
+	go mod edit -go=$(MIN_GO_VERSION) go.mod
+	cd ldotel && go mod edit -go=$(MIN_GO_VERSION) go.mod
+	cd testservice && go mod edit -go=$(MIN_GO_VERSION) go.mod
+	cd ./.github/variables && sed -i.bak "s#min=[^ ]*#min=$(MIN_GO_VERSION)#g" go-versions.env && rm go-versions.env.bak
+
 clean: workspace-clean
 	rm -rf ./bin/
 
@@ -143,4 +149,4 @@ run-contract-tests:
 
 contract-tests: build-contract-tests start-contract-test-service-bg run-contract-tests
 
-.PHONY: build-contract-tests start-contract-test-service start-contract-test-service-bg run-contract-tests contract-tests
+.PHONY: build-contract-tests start-contract-test-service start-contract-test-service-bg run-contract-tests contract-tests bump-min-go-version

README.md

@@ -8,10 +8,15 @@
 
 ## Supported Go versions
 
-This version of the LaunchDarkly SDK supports Go version 1.21 or higher. 
+The SDK supports the 'latest' and 'penultimate' Go versions defined in [this file](./.github/variables/go-versions.env).
 
-The policy for this SDK follows that of the official Go [Release Policy](https://go.dev/doc/devel/release): each major Go release is supported until there
-are two newer major releases.
+LaunchDarkly intends to keep those versions up-to-date with the Go project's latest two releases, which represents a support
+period of roughly 1 year. This policy is intended to match Go's official [Release Policy](https://go.dev/doc/devel/release): 
+each major Go release is supported until there are two newer major releases.
+
+Additionally, a 'minimum' version is tested in CI but not officially supported. This minimum version is found in [go.mod](./go.mod).
+This version may be [bumped](./CONTRIBUTING.md#bumping-the-minimum-go-version) from time to time as new Go features 
+become available that are useful to the SDK.
 
 ## Getting started
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/launchdarkly/go-server-sdk/v7
 
-go 1.21
+go 1.18
 
 require (
 	github.com/fsnotify/fsnotify v1.4.7
@@ -15,8 +15,8 @@ require (
 	github.com/launchdarkly/go-test-helpers/v3 v3.0.2
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/stretchr/testify v1.7.0
-	golang.org/x/exp v0.0.0-20220823124025-807a23277127
-	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e
+	golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa
+	golang.org/x/sync v0.8.0
 	gopkg.in/ghodss/yaml.v1 v1.0.0
 )
 

go.sum

@@ -59,9 +59,13 @@ golang.org/x/crypto v0.17.0 h1:r8bRNjWL3GshPW3gkd+RpvzWrZAwPS49OmTGZ/uhM4k=
 golang.org/x/crypto v0.17.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
 golang.org/x/exp v0.0.0-20220823124025-807a23277127 h1:S4NrSKDfihhl3+4jSTgwoIevKxX9p7Iv9x++OEIptDo=
 golang.org/x/exp v0.0.0-20220823124025-807a23277127/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
+golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa h1:ELnwvuAXPNtPk1TJRuGkI9fDTwym6AYBu0qzT8AcHdI=
+golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa/go.mod h1:akd2r19cwCdwSwWeIdzYQGa/EZZyqcOdwWiwj5L5eKQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e h1:vcxGaoTs7kV8m5Np9uUNQin4BrLOthgV7252N8V+FwY=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=

internal/broadcasters.go

@@ -1,8 +1,9 @@
 package internal
 
 import (
-	"slices"
 	"sync"
+
+	"golang.org/x/exp/slices"
 )
 
 // This file defines the publish-subscribe model we use for various status/event types in the SDK.

internal/endpoints/configure_endpoints_test.go

@@ -2,12 +2,13 @@ package endpoints
 
 import (
 	"fmt"
+	"strings"
+	"testing"
+
 	"github.com/launchdarkly/go-sdk-common/v3/ldlog"
 	"github.com/launchdarkly/go-sdk-common/v3/ldlogtest"
 	"github.com/launchdarkly/go-server-sdk/v7/interfaces"
 	"github.com/stretchr/testify/assert"
-	"strings"
-	"testing"
 )
 
 func TestDefaultURISelectedIfNoCustomURISpecified(t *testing.T) {

ldotel/go.mod

@@ -1,6 +1,6 @@
 module github.com/launchdarkly/go-server-sdk/ldotel
 
-go 1.21
+go 1.18
 
 require (
 	github.com/launchdarkly/go-sdk-common/v3 v3.1.0

ldotel/tracing_hook_test.go

@@ -11,8 +11,8 @@ import (
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/sdk/trace/tracetest"
 )
-import "go.opentelemetry.io/otel/sdk/trace/tracetest"
 
 func configureMemoryExporter() *tracetest.InMemoryExporter {
 	exporter := tracetest.NewInMemoryExporter()

testservice/go.mod

@@ -1,6 +1,6 @@
 module github.com/launchdarkly/go-server-sdk/v7/testservice
 
-go 1.21
+go 1.18
 
 require (
 	github.com/gorilla/mux v1.8.0
@@ -15,14 +15,14 @@ require (
 	github.com/launchdarkly/ccache v1.1.0 // indirect
 	github.com/launchdarkly/eventsource v1.6.2 // indirect
 	github.com/launchdarkly/go-jsonstream/v3 v3.0.0 // indirect
-	github.com/launchdarkly/go-sdk-events/v3 v3.2.0 // indirect
+	github.com/launchdarkly/go-sdk-events/v3 v3.4.0 // indirect
 	github.com/launchdarkly/go-semver v1.0.2 // indirect
 	github.com/launchdarkly/go-server-sdk-evaluation/v3 v3.0.0 // indirect
 	github.com/launchdarkly/go-test-helpers/v2 v2.3.1 // indirect
 	github.com/mailru/easyjson v0.7.6 // indirect
 	github.com/patrickmn/go-cache v2.1.0+incompatible // indirect
-	golang.org/x/exp v0.0.0-20220823124025-807a23277127 // indirect
-	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e // indirect
+	golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa // indirect
+	golang.org/x/sync v0.8.0 // indirect
 )
 
 replace github.com/launchdarkly/go-server-sdk/v7 => ../

testservice/go.sum

@@ -19,8 +19,8 @@ github.com/launchdarkly/go-jsonstream/v3 v3.0.0 h1:qJF/WI09EUJ7kSpmP5d1Rhc81NQdY
 github.com/launchdarkly/go-jsonstream/v3 v3.0.0/go.mod h1:/1Gyml6fnD309JOvunOSfyysWbZ/ZzcA120gF/cQtC4=
 github.com/launchdarkly/go-sdk-common/v3 v3.1.0 h1:KNCP5rfkOt/25oxGLAVgaU1BgrZnzH9Y/3Z6I8bMwDg=
 github.com/launchdarkly/go-sdk-common/v3 v3.1.0/go.mod h1:mXFmDGEh4ydK3QilRhrAyKuf9v44VZQWnINyhqbbOd0=
-github.com/launchdarkly/go-sdk-events/v3 v3.2.0 h1:FUby/4cUSVDghCkFDpvy+7vZlIW4+CK95HjQnuqGXVs=
-github.com/launchdarkly/go-sdk-events/v3 v3.2.0/go.mod h1:oepYWQ2RvvjfL2WxkE1uJJIuRsIMOP4WIVgUpXRPcNI=
+github.com/launchdarkly/go-sdk-events/v3 v3.4.0 h1:22sVSEDEXpdOEK3UBtmThwsUHqc+cbbe/pJfsliBAA4=
+github.com/launchdarkly/go-sdk-events/v3 v3.4.0/go.mod h1:oepYWQ2RvvjfL2WxkE1uJJIuRsIMOP4WIVgUpXRPcNI=
 github.com/launchdarkly/go-semver v1.0.2 h1:sYVRnuKyvxlmQCnCUyDkAhtmzSFRoX6rG2Xa21Mhg+w=
 github.com/launchdarkly/go-semver v1.0.2/go.mod h1:xFmMwXba5Mb+3h72Z+VeSs9ahCvKo2QFUTHRNHVqR28=
 github.com/launchdarkly/go-server-sdk-evaluation/v3 v3.0.0 h1:nQbR1xCpkdU9Z71FI28bWTi5LrmtSVURy0UFcBVD5ZU=
@@ -29,7 +29,6 @@ github.com/launchdarkly/go-test-helpers/v2 v2.2.0/go.mod h1:L7+th5govYp5oKU9iN7T
 github.com/launchdarkly/go-test-helpers/v2 v2.3.1 h1:KXUAQVTeHNcWVDVQ94uEkybI+URXI9rEd7E553EsZFw=
 github.com/launchdarkly/go-test-helpers/v2 v2.3.1/go.mod h1:L7+th5govYp5oKU9iN7To5PgznBuIjBPn+ejqKR0avw=
 github.com/launchdarkly/go-test-helpers/v3 v3.0.2 h1:rh0085g1rVJM5qIukdaQ8z1XTWZztbJ49vRZuveqiuU=
-github.com/launchdarkly/go-test-helpers/v3 v3.0.2/go.mod h1:u2ZvJlc/DDJTFrshWW50tWMZHLVYXofuSHUfTU/eIwM=
 github.com/mailru/easyjson v0.7.6 h1:8yTIVnZgCoiM1TgqoeTl+LfU5Jg6/xL3QhGQnimLYnA=
 github.com/mailru/easyjson v0.7.6/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
@@ -41,16 +40,14 @@ github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5
 github.com/stretchr/testify v1.6.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/wsxiaoys/terminal v0.0.0-20160513160801-0940f3fc43a0 h1:3UeQBvD0TFrlVjOeLOBz+CPAI8dnbqNSVwUwRrkp7vQ=
 github.com/wsxiaoys/terminal v0.0.0-20160513160801-0940f3fc43a0/go.mod h1:IXCdmsXIht47RaVFLEdVnh1t+pgYtTAhQGj73kz+2DM=
-golang.org/x/exp v0.0.0-20220823124025-807a23277127 h1:S4NrSKDfihhl3+4jSTgwoIevKxX9p7Iv9x++OEIptDo=
-golang.org/x/exp v0.0.0-20220823124025-807a23277127/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
-golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e h1:vcxGaoTs7kV8m5Np9uUNQin4BrLOthgV7252N8V+FwY=
-golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa h1:ELnwvuAXPNtPk1TJRuGkI9fDTwym6AYBu0qzT8AcHdI=
+golang.org/x/exp v0.0.0-20240808152545-0cdaa3abc0fa/go.mod h1:akd2r19cwCdwSwWeIdzYQGa/EZZyqcOdwWiwj5L5eKQ=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0 h1:hjy8E9ON/egN1tAYqKb61G10WtihqetD4sz2H+8nIeA=
-gopkg.in/yaml.v3 v3.0.0/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=