slogr: fix unintended API break in v0.8.0 (#253)

* github: check for API changes with Go 1.21.x

An API break in https://github.com/go-logr/logr/pull/237/files#r1434203442
wasn't noticed because the apidiff tool ran with 1.20.x.

* slogr: fix unintended API break in v0.8.0

logr v0.7.0 had slogr.NewSlogHandler. We must keep that function for API
compatibility. https://github.com/go-logr/logr/pull/237/files#r1434203442
accidentally renamed it.

.github/workflows/apidiff.yaml

@@ -13,7 +13,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@0c52d547c9bc32b1aa3301fd7a9cb496313a4491 # v5.0.0
         with:
-          go-version: 1.20.x
+          go-version: 1.21.x
       - name: Add GOBIN to PATH
         run: echo "PATH=$(go env GOPATH)/bin:$PATH" >>$GITHUB_ENV
       - name: Install dependencies

slogr/slogr.go

@@ -40,6 +40,13 @@ func NewLogr(handler slog.Handler) logr.Logger {
 	return logr.FromSlogHandler(handler)
 }
 
+// NewSlogHandler returns a slog.Handler which writes to the same sink as the logr.Logger.
+//
+// Deprecated: use [logr.ToSlogHandler] instead.
+func NewSlogHandler(logger logr.Logger) slog.Handler {
+	return logr.ToSlogHandler(logger)
+}
+
 // ToSlogHandler returns a slog.Handler which writes to the same sink as the logr.Logger.
 //
 // Deprecated: use [logr.ToSlogHandler] instead.