Merge branch 'master' into da4/solid-primitive-is-skew

Author: dassaf4

common/api/core-backend.api.md

@@ -4589,9 +4589,6 @@ export class IModelNative {
     static get platform(): typeof IModelJsNative;
 }
 
-// @internal (undocumented)
-export const _implicitTxn: unique symbol;
-
 // @beta
 export type ImplicitWriteEnforcement = "allow" | "log" | "throw";
 

common/api/summary/core-backend.exports.csv

@@ -367,7 +367,6 @@ public;class;IModelJsFs
 public;class;IModelJsFsStats
 public;interface;IModelNameArg
 internal;class;IModelNative
-internal;const;_implicitTxn
 beta;type;ImplicitWriteEnforcement
 public;class;InformationContentElement
 preview;class;InformationContentElement

common/changes/@itwin/core-backend/nam-linear-referencing-remove-implicit-txn_2026-05-11-17-13.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "",
+      "type": "none",
+      "packageName": "@itwin/core-backend"
+    }
+  ],
+  "packageName": "@itwin/core-backend",
+  "email": "50554904+hl662@users.noreply.github.com"
+}

common/changes/@itwin/linear-referencing-backend/nam-linear-referencing-remove-implicit-txn_2026-05-11-17-13.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "",
+      "type": "none",
+      "packageName": "@itwin/linear-referencing-backend"
+    }
+  ],
+  "packageName": "@itwin/linear-referencing-backend",
+  "email": "50554904+hl662@users.noreply.github.com"
+}

core/backend/src/internal/cross-package.ts

@@ -6,6 +6,5 @@
 export { IModelJsNative, NativeCloudSqlite, NativeLoggerCategory } from "@bentley/imodeljs-native";
 export { IModelNative } from "./NativePlatform";
 export {
-  _implicitTxn,
   _nativeDb,
 } from "./Symbols";

docs/learning/backend/IModelDbReadwrite.md

@@ -8,11 +8,21 @@ A backend can make the following kinds of changes:
 - [Create or update Models](./CreateModels.md)
 - [Reserve Codes](./ReserveCodes.md)
 
-Use [IModelDb.saveChanges]($backend) to commit changes locally. [BriefcaseDb.txns]($backend) manages local transactions, it supports local undo/redo.
+Use [IModelDb.saveChanges]($backend) to commit changes locally. [BriefcaseDb.txns]($backend) manages local transactions and supports undo/redo of pending local changes — those saved via [IModelDb.saveChanges]($backend) but not yet pushed. Once changes are pushed to iModelHub via [BriefcaseDb.pushChanges]($backend), they become part of the permanent changeset history and can no longer be reversed using the local undo/redo stack.
 
 ## Pushing changes to iModelHub
 
 Use [BriefcaseDb.pushChanges]($backend) to push local changes to iModelHub as a changeset, so that others can see them. After a changeset is pushed to iModelHub, it becomes part of the iModel's permanent timeline. This method automatically [pulls and merges](./IModelDbSync.md) new ChangeSets from iModelHub.
 
 > Only a single application can push to iModelHub at a time. IModelDb.pushChanges automatically retries push on appropriate failures. However, it is possible that all retry attempts fail, if there are a lot of other applications pushing at the same time. In that case, push should be attempted again later.
 
+## Reversing pushed changesets
+
+While the local undo/redo stack is cleared after pushing, it is still possible to reverse the *effect* of previously-pushed changesets using [BriefcaseDb.revertAndPushChanges]($backend). This method applies the targeted changesets in reverse to produce a new "revert" changeset, which is then pushed to iModelHub. Before calling it, the briefcase must be "clean": it must have no unsaved changes (`hasUnsavedChanges` must be false) and no pending transactions (`txns.hasPendingTxns` must be false). Save and push local changes first, or discard them, before attempting the revert. The original changesets are **not** removed from iModelHub's timeline — the history is append-only and immutable.
+
+| Scenario | Mechanism |
+|---|---|
+| Undo/redo **unpushed** local changes | `txns.reverseTxns` / `txns.reinstateTxn` |
+| Reverse the effect of **pushed** changesets | `BriefcaseDb.revertAndPushChanges({ toIndex })` |
+| Remove a changeset from history entirely | Not possible — iModelHub timeline is immutable |
+

domains/linear-referencing/backend/src/LinearReferencingElementAspects.ts

@@ -7,7 +7,7 @@
  */
 
 import { Id64String, JsonUtils } from "@itwin/core-bentley";
-import { _implicitTxn, EditTxn, ElementMultiAspect, IModelDb } from "@itwin/core-backend";
+import { EditTxn, ElementMultiAspect, IModelDb } from "@itwin/core-backend";
 import { RelatedElement } from "@itwin/core-common";
 import {
   DistanceExpressionProps, LinearlyReferencedAtLocationAspectProps, LinearlyReferencedFromToLocationAspectProps,
@@ -89,8 +89,13 @@ export class LinearlyReferencedAtLocation extends LinearlyReferencedLocation {
 
   public static insert(txnOrIModel: EditTxn | IModelDb, locatedElementId: Id64String,
     at: DistanceExpression, fromReferentId?: Id64String): void {
-    const txn = txnOrIModel instanceof EditTxn ? txnOrIModel : txnOrIModel[_implicitTxn];
-    txn.insertAspect(this.toProps(locatedElementId, at, fromReferentId));
+    const aspectProps = this.toProps(locatedElementId, at, fromReferentId);
+    if (txnOrIModel instanceof EditTxn)
+      txnOrIModel.insertAspect(aspectProps);
+    else {
+      // eslint-disable-next-line @typescript-eslint/no-deprecated -- deprecated IModelDb overload is intentionally preserved for backward compatibility.
+      txnOrIModel.elements.insertAspect(aspectProps);
+    }
   }
 }
 
@@ -147,7 +152,12 @@ export class LinearlyReferencedFromToLocation extends LinearlyReferencedLocation
 
   public static insert(txnOrIModel: EditTxn | IModelDb, locatedElementId: Id64String,
     from: DistanceExpression, to: DistanceExpression, fromReferentId?: Id64String, toReferentId?: Id64String): void {
-    const txn = txnOrIModel instanceof EditTxn ? txnOrIModel : txnOrIModel[_implicitTxn];
-    txn.insertAspect(this.toProps(locatedElementId, from, to, fromReferentId, toReferentId));
+    const aspectProps = this.toProps(locatedElementId, from, to, fromReferentId, toReferentId);
+    if (txnOrIModel instanceof EditTxn)
+      txnOrIModel.insertAspect(aspectProps);
+    else {
+      // eslint-disable-next-line @typescript-eslint/no-deprecated -- deprecated IModelDb overload is intentionally preserved for backward compatibility.
+      txnOrIModel.elements.insertAspect(aspectProps);
+    }
   }
 }