jschoubben
e34fcbeda3
A blind write after a read could lose the build of the publish that wrote first until a bundle restart learned it again. Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig
67 lines
2.1 KiB
Go
67 lines
2.1 KiB
Go
package main
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import (
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"encoding/json"
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"reflect"
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"testing"
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stdio "git.novox.be/novox/mesh-sdk/go"
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"distribution/internal/holder"
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)
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// casMem is a kept state with revisions; before writes it lets another writer write first, once.
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type casMem struct {
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value []byte
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rev uint64
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before func()
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}
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func (m *casMem) Get(string) (*stdio.StateEntry, error) {
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if m.value == nil {
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return nil, nil
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}
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return &stdio.StateEntry{Value: m.value, Revision: m.rev}, nil
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}
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func (m *casMem) write(v any, at uint64) (uint64, error) {
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if f := m.before; f != nil {
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m.before = nil
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f()
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}
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if m.rev != at {
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return 0, stdio.ErrChanged
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}
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m.value, _ = json.Marshal(v)
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m.rev++
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return m.rev, nil
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}
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func (m *casMem) Create(_ string, v any) (uint64, error) { return m.write(v, 0) }
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func (m *casMem) Update(_ string, v any, rev uint64) (uint64, error) { return m.write(v, rev) }
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// TestTwoFirstPublishesAtOnceAreBothKept: the publishing builds are written with compare-and-set, so a writer that lost
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// the race reads again and neither build is lost (A3f finding 2).
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func TestTwoFirstPublishesAtOnceAreBothKept(t *testing.T) {
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m := &casMem{}
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m.before = func() {
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// Another tools process learns mesh-build-go's build first.
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m.value, _ = json.Marshal(holder.Publishing{Name: holder.PublishingKey, Modules: map[string][]string{"mesh-build-go": {"fp-go"}}})
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m.rev = 1
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}
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if learnt, err := learnInto(m, "mesh-build-node", "fp-node", 3); err != nil || !learnt {
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t.Fatalf("learnInto = %v, %v", learnt, err)
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}
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var got holder.Publishing
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_ = json.Unmarshal(m.value, &got)
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want := map[string][]string{"mesh-build-go": {"fp-go"}, "mesh-build-node": {"fp-node"}}
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if !reflect.DeepEqual(got.Modules, want) {
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t.Errorf("kept %v, want both builds %v", got.Modules, want)
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}
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if learnt, err := learnInto(m, "mesh-build-node", "fp-node", 3); err != nil || learnt {
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t.Errorf("learning a kept build again = %v, %v, want not new and no write", learnt, err)
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}
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m.before = func() { m.rev++ }
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if _, err := learnInto(m, "mesh-build-oci", "fp-oci", 1); err == nil {
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t.Error("a write lost on every attempt answered no error")
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}
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}
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