fix(distributed): name both revisions in the stale error

"stale model config revision" reported only that two hashes differed.
It named neither, so an operator could not tell an edited configuration
from a revision that is not reproducible for one unchanged file, and the
failing value appears in no table.

The error now carries the revision the request brought and the one the
controller holds. It still wraps ErrStaleModelConfigRevision, so callers
that classify the error keep working.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude Code:claude-opus-5 [golangci-lint]

core/services/nodes/registry.go

@@ -1159,11 +1159,28 @@ func requireCurrentRevision(tx *gorm.DB, modelName, revision string) error {
 		return err
 	}
 	if state.ConfigRevision != revision {
-		return ErrStaleModelConfigRevision
+		// Name both sides. "stale model config revision" on its own says only
+		// that two hashes differ, which leaves an operator no way to tell an
+		// edited configuration from a revision that is not reproducible for one
+		// unchanged file.
+		return fmt.Errorf("%w (request carries %s, controller holds %s)",
+			ErrStaleModelConfigRevision, shortRevision(revision), shortRevision(state.ConfigRevision))
 	}
 	return nil
 }
 
+// shortRevision trims a revision for log and error output. The full value is a
+// sha256 hex digest; the leading bytes identify it well enough to compare two.
+func shortRevision(revision string) string {
+	if revision == "" {
+		return "(none)"
+	}
+	if len(revision) > 12 {
+		return revision[:12]
+	}
+	return revision
+}
+
 func validateRevisionWrite(modelName, revision string, revisionRequired bool) error {
 	if modelName == "" {
 		return fmt.Errorf("model name is required")

core/services/nodes/revision_error_detail_test.go

@@ -0,0 +1,24 @@
+package nodes
+
+import (
+	"errors"
+	"fmt"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Stale revision error detail", func() {
+	It("keeps errors.Is matching so callers can still classify it", func() {
+		err := fmt.Errorf("%w (request carries %s, controller holds %s)",
+			ErrStaleModelConfigRevision, shortRevision("aaaabbbbccccdddd"), shortRevision("1111222233334444"))
+		Expect(errors.Is(err, ErrStaleModelConfigRevision)).To(BeTrue())
+		Expect(err.Error()).To(ContainSubstring("stale model config revision"))
+	})
+
+	It("names both revisions so an operator can tell which side moved", func() {
+		Expect(shortRevision("aaaabbbbccccdddd")).To(Equal("aaaabbbbcccc"))
+		Expect(shortRevision("short")).To(Equal("short"))
+		Expect(shortRevision("")).To(Equal("(none)"))
+	})
+})