From 80a7cee6f35e08aa876210b210c1c23f6716d18a Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Wed, 4 Nov 2026 11:47:59 +0100
Subject: [PATCH] CAT-K3: each operation of the records' ledger types has its
 effect on a head, tested against the manifest's own types

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig
---
 .../cmd/mesh-knowledge/ledgertype_test.go     | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 modules/mesh-knowledge/cmd/mesh-knowledge/ledgertype_test.go

diff --git a/modules/mesh-knowledge/cmd/mesh-knowledge/ledgertype_test.go b/modules/mesh-knowledge/cmd/mesh-knowledge/ledgertype_test.go
new file mode 100644
index 00000000..0449bc1e
--- /dev/null
+++ b/modules/mesh-knowledge/cmd/mesh-knowledge/ledgertype_test.go
@@ -0,0 +1,87 @@
+package main
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/buscalls"
+)
+
+// Each operation of the ledger's types has the effect on a head the design says (ADR 0597 §2, to-be 55 §2.1): a
+// write-section puts the section's title and digest, never its text, among the pending sections; an operation that
+// makes a version sets the head and empties them; the others set the head and leave them.
+func TestEachOperationHasItsEffectOnAHead(t *testing.T) {
+	text := "the section's text"
+	for _, c := range []struct {
+		op          string
+		body        map[string]any
+		pendingKept bool // the pending sections stand after it
+		clears      bool // the pending sections are emptied by it
+	}{
+		{OpReserve, map[string]any{"entry": map[string]any{"v": 1}}, false, false},
+		{OpPropose, map[string]any{"entry": map[string]any{"v": 1}, "pending-sections": map[string]any{}}, false, true},
+		{OpSubmit, map[string]any{"entry": map[string]any{"v": 1}, "pending-sections": map[string]any{}}, false, true},
+		{OpDrop, map[string]any{"entry": map[string]any{"v": 1}, "pending-sections": map[string]any{}}, false, true},
+		{OpImport, map[string]any{"entry": map[string]any{"v": 1}, "pending-sections": map[string]any{}}, false, true},
+		{OpForm, map[string]any{"entry": map[string]any{"v": 1}, "pending-sections": map[string]any{}}, false, true},
+		{OpTakeOver, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpReview, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpAsk, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpWarrant, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpAccept, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpWithdraw, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpRetract, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+		{OpDraft, map[string]any{"entry": map[string]any{"v": 1}}, true, false},
+	} {
+		f := newFakeLedger(t)
+		apply := func(op string, body map[string]any) {
+			t.Helper()
+			raw, _ := json.Marshal(body)
+			var got buscalls.Applied
+			if err := f.Call(buscalls.LedgerApply, buscalls.ApplyRequest{Ledger: LedgerName, Instance: "decision/0001", Operation: op, Body: raw}, &got); err != nil {
+				t.Fatalf("%s: %v", op, err)
+			}
+		}
+		apply(OpWriteSection, map[string]any{"title": "Context", "text": text, "digest": SectionDigest(text)})
+		body := map[string]any{"kind": "decision", "number": 1}
+		for k, v := range c.body {
+			body[k] = v
+		}
+		apply(c.op, body)
+		var st map[string]any
+		_ = json.Unmarshal(mustJSON(t, f.state["decision/0001"]), &st)
+		pending, _ := st["pending-sections"].(map[string]any)
+		switch {
+		case c.clears && len(pending) != 0:
+			t.Errorf("%s leaves pending sections %v", c.op, pending)
+		case c.pendingKept && len(pending) != 1:
+			t.Errorf("%s does not keep the pending sections: %v", c.op, pending)
+		}
+		if c.op == OpReserve && len(pending) != 1 {
+			t.Errorf("reserve touched the pending sections: %v", pending)
+		}
+		if st["entry"] == nil || st["sequence"] != float64(2) {
+			t.Errorf("%s: head %v", c.op, st)
+		}
+		if a, _ := st["author"].(map[string]any); a["account"] != "mesh-knowledge" {
+			t.Errorf("%s: author %v", c.op, st["author"])
+		}
+		if raw, _ := json.Marshal(st); json.Valid(raw) && strings.Contains(string(raw), text) {
+			t.Errorf("%s: the head holds the section's text", c.op)
+		}
+	}
+}
+
+// A write-section whose digest is not its text's is refused by apply, and an operation the type does not allow is too.
+func TestTheLedgerRefusesADigestThatIsNotTheTextsAndAnOperationTheTypeLacks(t *testing.T) {
+	f := newFakeLedger(t)
+	var got buscalls.Applied
+	bad, _ := json.Marshal(map[string]any{"title": "Context", "text": "a", "digest": SectionDigest("b")})
+	if err := f.Call(buscalls.LedgerApply, buscalls.ApplyRequest{Ledger: LedgerName, Instance: "decision/0001", Operation: OpWriteSection, Body: bad}, &got); err == nil {
+		t.Error("a digest of another text was taken")
+	}
+	if err := f.Call(buscalls.LedgerApply, buscalls.ApplyRequest{Ledger: LedgerName, Instance: "decision/0001", Operation: "delete"}, &got); err == nil {
+		t.Error("an operation the type lacks was taken")
+	}
+}