From fbcbe4633b86b739626b485e1b09737f50ac1f42 Mon Sep 17 00:00:00 2001
From: suyu <1643689728@qq.com>
Date: Thu, 27 Aug 2026 12:00:47 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20=E4=BF=AE=E6=AD=A3=E6=A2=AF=E5=BD=A2?=
 =?UTF-8?q?=E5=9B=BE=E7=BD=91=E7=BB=9C=E6=B3=A8=E9=87=8A=E5=BD=92=E5=B1=9E?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 app/src/domain/control_logic_model.cpp       | 40 ++++++++-
 app/src/domain/control_logic_model.h         |  1 +
 app/src/services/logic_editor_service.cpp    | 85 ++++++++++++++++++--
 app/src/services/logic_editor_service.h      |  6 +-
 app/src/ui/logic_editor_widget.cpp           | 16 +---
 app/src/ui/main_window.cpp                   | 18 ++---
 app/src/ui/main_window.h                     |  2 +-
 app/src/ui/main_window.ui                    |  4 +-
 app/tests/domain_tests.cpp                   | 22 +++++
 app/tests/logic_editor_service_tests.cpp     | 82 ++++++++++++++++++-
 app/tests/project_management_tests.cpp       | 16 ++++
 app/tests/runtime_panel_controller_tests.cpp | 18 ++---
 12 files changed, 263 insertions(+), 47 deletions(-)

diff --git a/app/src/domain/control_logic_model.cpp b/app/src/domain/control_logic_model.cpp
index ba6267f..818daee 100644
--- a/app/src/domain/control_logic_model.cpp
+++ b/app/src/domain/control_logic_model.cpp
@@ -454,7 +454,7 @@ bool LadderRung::validateStructure(std::string *error) const
     if (containsLineBreak(comment)
         || comment.size() > ProjectLimits::kMaximumRungCommentBytes)
     {
-        setError(error, "梯形图行注释必须是最多 128 个 UTF-8 字节的单行文本");
+        setError(error, "网络注释必须是最多 128 个 UTF-8 字节的单行文本");
         return false;
     }
     if (cells.empty())
@@ -531,6 +531,33 @@ bool LadderRung::validateForRunning(std::string *error) const
     return true;
 }
 
+std::size_t ControlLogic::networkHeadIndex(std::size_t rung_index) const
+{
+    if (rung_index >= rungs.size())
+    {
+        return rungs.size();
+    }
+    while (rung_index > 0U)
+    {
+        const std::string &upper_id = rungs[rung_index - 1U].id;
+        const std::string &lower_id = rungs[rung_index].id;
+        const bool connected_to_previous = std::any_of(
+            verticalConnections.cbegin(),
+            verticalConnections.cend(),
+            [&upper_id, &lower_id](const VerticalConnection &connection)
+            {
+                return connection.upperRungId == upper_id
+                    && connection.lowerRungId == lower_id;
+            });
+        if (!connected_to_previous)
+        {
+            break;
+        }
+        --rung_index;
+    }
+    return rung_index;
+}
+
 bool ControlLogic::validate(
     const ProjectLimitSettings &limits, std::string *error) const
 {
@@ -641,6 +668,17 @@ bool ControlLogic::validateStructure(
             return false;
         }
     }
+    for (std::size_t row = 1U; row < rungs.size(); ++row)
+    {
+        if (!rungs[row].comment.empty() && networkHeadIndex(row) != row)
+        {
+            setError(
+                error,
+                "第 " + std::to_string(row + 1U)
+                    + " 行不是网络首行，不能保存网络注释");
+            return false;
+        }
+    }
     return true;
 }
 
diff --git a/app/src/domain/control_logic_model.h b/app/src/domain/control_logic_model.h
index 1bc373c..4f53b4f 100644
--- a/app/src/domain/control_logic_model.h
+++ b/app/src/domain/control_logic_model.h
@@ -175,6 +175,7 @@ struct ControlLogic
     bool enabled = true;
     std::vector<VerticalConnection> verticalConnections;
 
+    std::size_t networkHeadIndex(std::size_t rung_index) const;
     bool validate(
         const ProjectLimitSettings &limits,
         std::string *error = nullptr) const;
diff --git a/app/src/services/logic_editor_service.cpp b/app/src/services/logic_editor_service.cpp
index 6d28471..27cc7e5 100644
--- a/app/src/services/logic_editor_service.cpp
+++ b/app/src/services/logic_editor_service.cpp
@@ -590,6 +590,45 @@ bool LogicEditorService::rungsEqual(
         || nodesEqual(*left.output, *right.output);
 }
 
+bool LogicEditorService::mergeNetworkComments(
+    ControlLogic *logic, std::string *error)
+{
+    if (logic == nullptr)
+    {
+        if (error != nullptr)
+        {
+            *error = "未找到控制逻辑";
+        }
+        return false;
+    }
+    for (std::size_t row = 1U; row < logic->rungs.size(); ++row)
+    {
+        const std::size_t head = logic->networkHeadIndex(row);
+        if (head == row || logic->rungs[row].comment.empty())
+        {
+            continue;
+        }
+        std::string &head_comment = logic->rungs[head].comment;
+        std::string &branch_comment = logic->rungs[row].comment;
+        if (!head_comment.empty() && head_comment != branch_comment)
+        {
+            if (error != nullptr)
+            {
+                *error = "无法合并网络：第 " + std::to_string(head + 1U)
+                    + " 行和第 " + std::to_string(row + 1U)
+                    + " 行存在不同注释，请先统一或清空其中一条";
+            }
+            return false;
+        }
+        if (head_comment.empty())
+        {
+            head_comment = branch_comment;
+        }
+        branch_comment.clear();
+    }
+    return true;
+}
+
 bool LogicEditorService::cellsEqual(
     const LadderCell &left, const LadderCell &right)
 {
@@ -691,6 +730,19 @@ const LadderRung *LogicEditorService::findRung(
     return found == logic->rungs.cend() ? nullptr : &*found;
 }
 
+const LadderRung *LogicEditorService::findNetworkHeadRung(
+    const std::string &logic_id, const std::string &rung_id) const
+{
+    const ControlLogic *logic = findLogic(logic_id);
+    if (logic == nullptr)
+    {
+        return nullptr;
+    }
+    const std::size_t row = rungIndex(*logic, rung_id);
+    const std::size_t head = logic->networkHeadIndex(row);
+    return head == logic->rungs.size() ? nullptr : &logic->rungs[head];
+}
+
 const LadderCell *LogicEditorService::findCell(
     const std::string &logic_id,
     const std::string &rung_id,
@@ -1217,13 +1269,13 @@ LogicEditorResult LogicEditorService::removeRungs(
     return {true, LogicEditorError::None, {}, rung_ids.front()};
 }
 
-LogicEditorResult LogicEditorService::updateRungComment(
+LogicEditorResult LogicEditorService::updateNetworkComment(
     const std::string &logic_id,
     const std::string &rung_id,
     const std::string &comment)
 {
-    const LadderRung *rung = findRung(logic_id, rung_id);
-    if (rung == nullptr)
+    const LadderRung *head = findNetworkHeadRung(logic_id, rung_id);
+    if (head == nullptr)
     {
         return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
     }
@@ -1232,17 +1284,18 @@ LogicEditorResult LogicEditorService::updateRungComment(
     {
         return failure(
             LogicEditorError::InvalidOperation,
-            "行注释必须是最多 128 个 UTF-8 字节的单行文本");
+            "网络注释必须是最多 128 个 UTF-8 字节的单行文本");
     }
-    if (rung->comment == comment)
+    if (head->comment == comment)
     {
-        return {true, LogicEditorError::None, {}, rung_id};
+        return {true, LogicEditorError::None, {}, head->id};
     }
+    const std::string head_rung_id = head->id;
     HistoryState before = captureState();
     Project &project = project_service_.editProject();
-    editableRung(editableLogic(&project, logic_id), rung_id)->comment = comment;
+    editableRung(editableLogic(&project, logic_id), head_rung_id)->comment = comment;
     recordHistory(std::move(before));
-    return {true, LogicEditorError::None, {}, rung_id};
+    return {true, LogicEditorError::None, {}, head_rung_id};
 }
 
 LogicEditResult LogicEditorService::applyConditionAndAdvance(
@@ -1584,6 +1637,11 @@ LogicEditorResult LogicEditorService::setVerticalConnectionRange(
         }
     }
     std::string error;
+    if (connected && !mergeNetworkComments(editable, &error))
+    {
+        rollbackEdit(std::move(before), modified_before);
+        return failure(LogicEditorError::InvalidOperation, error);
+    }
     if (!editable->validateStructure(project_service_.projectLimits(), &error))
     {
         rollbackEdit(std::move(before), modified_before);
@@ -2472,6 +2530,11 @@ LogicClipboardPasteResult LogicEditorService::pasteClipboard(
             }
         }
         std::string error;
+        if (!mergeNetworkComments(editable, &error))
+        {
+            rollbackEdit(std::move(before), modified_before);
+            return {failure(LogicEditorError::InvalidOperation, error), {}, {}};
+        }
         if (!editable->validateStructure(project_service_.projectLimits(), &error))
         {
             rollbackEdit(std::move(before), modified_before);
@@ -2687,6 +2750,12 @@ LogicClipboardPasteResult LogicEditorService::pasteClipboard(
         }
     }
     std::string error;
+    if (!fragment.verticalConnections.empty()
+        && !mergeNetworkComments(editable, &error))
+    {
+        rollbackEdit(std::move(before), modified_before);
+        return {failure(LogicEditorError::InvalidOperation, error), {}, {}};
+    }
     if (!editable->validateStructure(project_service_.projectLimits(), &error))
     {
         rollbackEdit(std::move(before), modified_before);
diff --git a/app/src/services/logic_editor_service.h b/app/src/services/logic_editor_service.h
index 839a24f..bf0153e 100644
--- a/app/src/services/logic_editor_service.h
+++ b/app/src/services/logic_editor_service.h
@@ -165,6 +165,8 @@ public:
     const ControlLogic *findLogic(const std::string &logic_id) const;
     const LadderRung *findRung(
         const std::string &logic_id, const std::string &rung_id) const;
+    const LadderRung *findNetworkHeadRung(
+        const std::string &logic_id, const std::string &rung_id) const;
     const LadderCell *findCell(
         const std::string &logic_id,
         const std::string &rung_id,
@@ -209,7 +211,7 @@ public:
     LogicEditorResult removeRungs(
         const std::string &logic_id,
         const std::vector<std::string> &rung_ids);
-    LogicEditorResult updateRungComment(
+    LogicEditorResult updateNetworkComment(
         const std::string &logic_id,
         const std::string &rung_id,
         const std::string &comment);
@@ -323,6 +325,8 @@ private:
         const ControlLogic &left, const ControlLogic &right);
     static bool rungsEqual(
         const LadderRung &left, const LadderRung &right);
+    static bool mergeNetworkComments(
+        ControlLogic *logic, std::string *error);
     static bool cellsEqual(
         const LadderCell &left, const LadderCell &right);
     static bool nodesEqual(const LogicNode &left, const LogicNode &right);
diff --git a/app/src/ui/logic_editor_widget.cpp b/app/src/ui/logic_editor_widget.cpp
index c529ccc..3e8551e 100644
--- a/app/src/ui/logic_editor_widget.cpp
+++ b/app/src/ui/logic_editor_widget.cpp
@@ -1055,21 +1055,7 @@ void LogicEditorWidget::rebuildRowLayout(const ControlLogic &logic)
     qreal next_top = kTop;
     for (std::size_t row = 0U; row < logic.rungs.size(); ++row)
     {
-        bool connected_to_previous = false;
-        if (row > 0U)
-        {
-            const std::string &upper_id = logic.rungs[row - 1U].id;
-            const std::string &lower_id = logic.rungs[row].id;
-            connected_to_previous = std::any_of(
-                logic.verticalConnections.cbegin(),
-                logic.verticalConnections.cend(),
-                [&upper_id, &lower_id](const VerticalConnection &connection)
-                {
-                    return connection.upperRungId == upper_id
-                        && connection.lowerRungId == lower_id;
-                });
-        }
-        const bool network_head = row == 0U || !connected_to_previous;
+        const bool network_head = logic.networkHeadIndex(row) == row;
         if (network_head)
         {
             next_top += kCommentBandHeight;
diff --git a/app/src/ui/main_window.cpp b/app/src/ui/main_window.cpp
index 435147a..66add13 100644
--- a/app/src/ui/main_window.cpp
+++ b/app/src/ui/main_window.cpp
@@ -878,8 +878,8 @@ void MainWindow::configureActions()
             });
     connect(ui_->deleteLogicAction, &QAction::triggered,
             this, &MainWindow::deleteSelectedLogicObject);
-    connect(ui_->editRungCommentAction, &QAction::triggered,
-            this, &MainWindow::editSelectedRungComment);
+    connect(ui_->editNetworkCommentAction, &QAction::triggered,
+            this, &MainWindow::editSelectedNetworkComment);
     addToolbarMenu(
         ui_->logicToolBar,
         tr("更多触点"),
@@ -994,7 +994,7 @@ void MainWindow::configureAppearance()
     ui_->addAddAction->setIcon(makeUiIcon(UiIcon::Add));
     ui_->addSubAction->setIcon(makeUiIcon(UiIcon::Subtract));
     ui_->addCompareAction->setIcon(makeUiIcon(UiIcon::Compare));
-    ui_->editRungCommentAction->setIcon(makeUiIcon(UiIcon::Comment));
+    ui_->editNetworkCommentAction->setIcon(makeUiIcon(UiIcon::Comment));
     ui_->syntaxCheckAction->setIcon(makeUiIcon(UiIcon::SyntaxCheck));
     ui_->doubleCoilCheckAction->setIcon(makeUiIcon(UiIcon::Coil));
     ui_->deleteLogicAction->setIcon(makeUiIcon(UiIcon::Delete));
@@ -1835,7 +1835,7 @@ void MainWindow::deleteLogicRung()
     statusBar()->showMessage(tr("当前行已删除，竖线连接已重新整理"), 3000);
 }
 
-void MainWindow::editSelectedRungComment()
+void MainWindow::editSelectedNetworkComment()
 {
     const std::string rung_id = logic_editor_widget_->selectedRungId();
     if (rung_id.empty())
@@ -1843,9 +1843,9 @@ void MainWindow::editSelectedRungComment()
         showProjectResult(tr("网络注释"), tr("请先选择一个梯形图网络"), false);
         return;
     }
-    const LadderRung *rung = logic_editor_service_.findRung(
+    const LadderRung *head = logic_editor_service_.findNetworkHeadRung(
         current_logic_id_, rung_id);
-    if (rung == nullptr)
+    if (head == nullptr)
     {
         return;
     }
@@ -1855,13 +1855,13 @@ void MainWindow::editSelectedRungComment()
         tr("网络注释"),
         tr("说明"),
         QLineEdit::Normal,
-        fromUtf8(rung->comment),
+        fromUtf8(head->comment),
         &accepted);
     if (!accepted)
     {
         return;
     }
-    const LogicEditorResult result = logic_editor_service_.updateRungComment(
+    const LogicEditorResult result = logic_editor_service_.updateNetworkComment(
         current_logic_id_, rung_id, toUtf8(comment));
     if (!result.succeeded)
     {
@@ -2453,7 +2453,7 @@ void MainWindow::updateModeUi(const QString &message)
     ui_->addAddAction->setEnabled(policy.allowsProjectEditing);
     ui_->addSubAction->setEnabled(policy.allowsProjectEditing);
     ui_->addCompareAction->setEnabled(policy.allowsProjectEditing);
-    ui_->editRungCommentAction->setEnabled(policy.allowsProjectEditing);
+    ui_->editNetworkCommentAction->setEnabled(policy.allowsProjectEditing);
     ui_->deleteLogicAction->setEnabled(policy.allowsProjectEditing);
     ui_->newProjectAction->setEnabled(policy.allowsProjectEditing);
     ui_->saveProjectAction->setEnabled(policy.allowsProjectEditing);
diff --git a/app/src/ui/main_window.h b/app/src/ui/main_window.h
index a52a154..1137f96 100644
--- a/app/src/ui/main_window.h
+++ b/app/src/ui/main_window.h
@@ -197,7 +197,7 @@ private:
     /** 删除当前选中的梯形图行 */
     void deleteLogicRung();
     /** 编辑当前网络的注释 */
-    void editSelectedRungComment();
+    void editSelectedNetworkComment();
     /** 规整并检查当前梯形图 */
     void runLogicSyntaxCheck();
     /** 单独检查当前梯形图中的重复线圈输出 */
diff --git a/app/src/ui/main_window.ui b/app/src/ui/main_window.ui
index a469d9d..d96b8d8 100644
--- a/app/src/ui/main_window.ui
+++ b/app/src/ui/main_window.ui
@@ -364,7 +364,7 @@
    <addaction name="addNormallyOpenAction"/>
    <addaction name="addNormallyClosedAction"/>
    <addaction name="addNormalCoilAction"/>
-   <addaction name="editRungCommentAction"/>
+   <addaction name="editNetworkCommentAction"/>
    <addaction name="separator"/>
    <addaction name="syntaxCheckAction"/>
   </widget>
@@ -1318,7 +1318,7 @@
     <string>在选中的空网格或横线处添加 D 值与常量比较条件</string>
    </property>
   </action>
-  <action name="editRungCommentAction">
+  <action name="editNetworkCommentAction">
    <property name="text">
     <string>网络注释</string>
    </property>
diff --git a/app/tests/domain_tests.cpp b/app/tests/domain_tests.cpp
index e5ace6c..eccb4e7 100644
--- a/app/tests/domain_tests.cpp
+++ b/app/tests/domain_tests.cpp
@@ -696,6 +696,28 @@ void testEdgeAndCommentBoundaries()
     comment_rung.comment = "第一行\r第二行";
     require(!comment_rung.validateStructure(), "a rung comment containing CR must be rejected");
 
+    ControlLogic commented_logic;
+    commented_logic.id = "commented-logic";
+    commented_logic.name = "Commented logic";
+    LadderRung head;
+    head.id = "head";
+    head.name = "Head";
+    head.comment = "Network comment";
+    LadderRung branch;
+    branch.id = "branch";
+    branch.name = "Branch";
+    branch.comment = "Hidden branch comment";
+    commented_logic.rungs = {head, branch};
+    commented_logic.verticalConnections = {
+        {"comment-edge", "head", "branch", 0}};
+    require(
+        commented_logic.networkHeadIndex(1U) == 0U
+            && !commented_logic.validateStructure(),
+        "a connected branch row must not persist a hidden network comment");
+    commented_logic.rungs[1].comment.clear();
+    require(commented_logic.validateStructure(),
+            "a connected network must be valid when only its head stores the comment");
+
     Project project = makeValidProject();
     project.registerComments = {
         {RegisterAddress{RegisterArea::M, 0}, "启动按钮"},
diff --git a/app/tests/logic_editor_service_tests.cpp b/app/tests/logic_editor_service_tests.cpp
index a5fb9c0..ef85638 100644
--- a/app/tests/logic_editor_service_tests.cpp
+++ b/app/tests/logic_editor_service_tests.cpp
@@ -192,6 +192,85 @@ void testIndependentVerticalConnectionsAndNetworkSplit()
         "the model must reject vertical edges between non-adjacent rows");
 }
 
+void testNetworkCommentsFollowNetworkHeadsAndMergeAtomically()
+{
+    Fixture fixture;
+    const std::string first = fixture.addRung();
+    const std::string second = fixture.addRung();
+    const std::string third = fixture.addRung();
+
+    require(
+        fixture.editor.updateNetworkComment(
+            fixture.logicId, second, "下方网络注释").succeeded,
+        "an independent lower network must accept its own comment");
+    fixture.editor.clearHistory();
+    const LogicEditorResult merged = fixture.editor.setVerticalConnection(
+        fixture.logicId, first, second, 4, true);
+    const ControlLogic *logic = fixture.editor.findLogic(fixture.logicId);
+    require(
+        merged.succeeded && logic->rungs[0].comment == "下方网络注释"
+            && logic->rungs[1].comment.empty()
+            && fixture.editor.findNetworkHeadRung(fixture.logicId, second)->id
+                == first,
+        "merging a commented lower network into an empty upper network must move the comment to the new head");
+    require(
+        fixture.editor.undo().succeeded
+            && fixture.editor.findRung(fixture.logicId, first)->comment.empty()
+            && fixture.editor.findRung(fixture.logicId, second)->comment
+                == "下方网络注释"
+            && fixture.editor.redo().succeeded,
+        "network merge comment movement must belong to the same undo transaction");
+
+    fixture.editor.clearHistory();
+    const LogicEditorResult edited_from_branch =
+        fixture.editor.updateNetworkComment(
+            fixture.logicId, second, "从支路编辑后的注释");
+    require(
+        edited_from_branch.succeeded && edited_from_branch.id == first
+            && fixture.editor.findRung(fixture.logicId, first)->comment
+                == "从支路编辑后的注释"
+            && fixture.editor.findRung(fixture.logicId, second)->comment.empty(),
+        "editing from a branch row must update only the network head comment");
+
+    require(
+        fixture.editor.updateNetworkComment(
+            fixture.logicId, third, "另一个网络注释").succeeded,
+        "the third independent network must accept a different comment");
+    fixture.editor.clearHistory();
+    fixture.projects.restoreModifiedState(false);
+    const LogicEditorResult conflict = fixture.editor.setVerticalConnection(
+        fixture.logicId, second, third, 4, true);
+    logic = fixture.editor.findLogic(fixture.logicId);
+    require(
+        !conflict.succeeded
+            && conflict.message.find("存在不同注释") != std::string::npos
+            && connectionAt(*logic, second, third, 4) == nullptr
+            && logic->rungs[0].comment == "从支路编辑后的注释"
+            && logic->rungs[2].comment == "另一个网络注释"
+            && !fixture.projects.isModified() && !fixture.editor.canUndo(),
+        "merging differently commented networks must fail without partial topology or history");
+
+    require(
+        fixture.editor.updateNetworkComment(
+            fixture.logicId, third, "从支路编辑后的注释").succeeded,
+        "the lower network comment must be editable before a retry");
+    fixture.editor.clearHistory();
+    require(
+        fixture.editor.setVerticalConnection(
+            fixture.logicId, second, third, 4, true).succeeded
+            && fixture.editor.findRung(fixture.logicId, third)->comment.empty(),
+        "merging equal network comments must keep one comment at the head");
+    const std::string connection_id = connectionAt(
+        *fixture.editor.findLogic(fixture.logicId), second, third, 4)->id;
+    require(
+        fixture.editor.removeVerticalConnections(
+            fixture.logicId, {connection_id}).succeeded
+            && fixture.editor.findRung(fixture.logicId, first)->comment
+                == "从支路编辑后的注释"
+            && fixture.editor.findRung(fixture.logicId, third)->comment.empty(),
+        "splitting a network must not duplicate its head comment");
+}
+
 void testInsertRowSplitsVerticalEdges()
 {
     Fixture fixture;
@@ -1149,7 +1228,7 @@ void testWholeRowClipboardInsertionAndLimit()
         source_node.succeeded
             && fixture.editor.setHorizontalWireRange(
                 fixture.logicId, second, 0, 1, true).succeeded
-            && fixture.editor.updateRungComment(
+            && fixture.editor.updateNetworkComment(
                 fixture.logicId, first, "整行复制注释").succeeded
             && fixture.editor.setVerticalConnection(
                 fixture.logicId, first, second, 2, true).succeeded,
@@ -1413,6 +1492,7 @@ int main()
     {
         testContinuousGridAndIndependentHorizontalWires();
         testIndependentVerticalConnectionsAndNetworkSplit();
+        testNetworkCommentsFollowNetworkHeadsAndMergeAtomically();
         testInsertRowSplitsVerticalEdges();
         testDeleteRowMergesOnlyContinuousEdges();
         testParallelBranchCreatesConnectedVisualRow();
diff --git a/app/tests/project_management_tests.cpp b/app/tests/project_management_tests.cpp
index e3026c2..cfa3785 100644
--- a/app/tests/project_management_tests.cpp
+++ b/app/tests/project_management_tests.cpp
@@ -128,6 +128,7 @@ Project makeExampleProject()
     logic.verticalConnections = {
         {"vertical-left", "rung-1", "rung-2", 0},
         {"vertical-right", "rung-1", "rung-2", 1}};
+    logic.rungs[1].comment.clear();
     project.controlLogics.push_back(std::move(logic));
     project.registerComments.push_back({
         RegisterAddress{RegisterArea::M, 0}, "Start signal"});
@@ -396,6 +397,21 @@ void testInvalidGridAndConnectionsAreRejected()
                 == ProjectStorageError::InvalidProject,
             "duplicate edges at one row boundary must be rejected");
 
+    QJsonObject hidden_comment = original;
+    logic = firstLogic(&hidden_comment);
+    rungs = logic.value(QStringLiteral("rungs")).toArray();
+    rung = rungs.at(1).toObject();
+    rung.insert(QStringLiteral("comment"), QStringLiteral("hidden branch comment"));
+    rungs.replace(1, rung);
+    logic.insert(QStringLiteral("rungs"), rungs);
+    replaceFirstLogic(&hidden_comment, logic);
+    const QString hidden_comment_path = directory.filePath(
+        "hidden-branch-comment.json");
+    writeBytes(hidden_comment_path, QJsonDocument(hidden_comment).toJson());
+    require(storage.load(hidden_comment_path.toStdString()).error
+                == ProjectStorageError::InvalidProject,
+            "a 2.0 project must reject comments stored on connected branch rows");
+
     QJsonObject non_adjacent = original;
     logic = firstLogic(&non_adjacent);
     edges = logic.value(QStringLiteral("verticalConnections")).toArray();
diff --git a/app/tests/runtime_panel_controller_tests.cpp b/app/tests/runtime_panel_controller_tests.cpp
index c8b4d8c..c78a45d 100644
--- a/app/tests/runtime_panel_controller_tests.cpp
+++ b/app/tests/runtime_panel_controller_tests.cpp
@@ -564,11 +564,14 @@ void testLadderLayoutAndDragDeletion()
                 logic_id, lower, 0, 1, true).succeeded
             && editor.setVerticalConnection(
                 logic_id, upper, lower, 2, true).succeeded
-            && editor.updateRungComment(
-                logic_id, upper, "主网络注释").succeeded
-            && editor.updateRungComment(
-                logic_id, lower, "支路注释不应重复").succeeded,
+            && editor.updateNetworkComment(
+                logic_id, lower, "主网络注释").succeeded,
         "layout fixture must create a connected two-row network");
+    require(
+        editor.findNetworkHeadRung(logic_id, lower)->id == upper
+            && editor.findRung(logic_id, upper)->comment == "主网络注释"
+            && editor.findRung(logic_id, lower)->comment.empty(),
+        "editing a branch row must store the comment only on the network head");
     editor.clearHistory();
 
     LogicEditorWidget widget(editor);
@@ -578,7 +581,6 @@ void testLadderLayoutAndDragDeletion()
     QCoreApplication::processEvents(QEventLoop::AllEvents);
 
     bool found_head_comment = false;
-    bool found_branch_comment = false;
     for (QGraphicsItem *item : widget.scene()->items())
     {
         auto *text = dynamic_cast<QGraphicsSimpleTextItem *>(item);
@@ -588,11 +590,9 @@ void testLadderLayoutAndDragDeletion()
         }
         found_head_comment = found_head_comment
             || text->text() == QStringLiteral("主网络注释");
-        found_branch_comment = found_branch_comment
-            || text->text() == QStringLiteral("支路注释不应重复");
     }
-    require(found_head_comment && !found_branch_comment,
-            "only the network-head comment must be rendered");
+    require(found_head_comment,
+            "the comment edited from a branch must render above the network head");
 
     constexpr qreal left_bus = 60.0;
     constexpr qreal cell_width = 96.0;