Document comparison crashes when the revised file contains tracked changes (w:ins/w:del)

[IuLeon]

Description

When using setRevisedFile() to compare two documents, the editor crashes if the revised file (the file passed to setRevisedFile) contains tracked changes (<w:ins>, <w:del> elements in the docx XML).

Steps to Reproduce

1.Open a clean document (no tracked changes) in edit mode
2.Call setRevisedFile({ url: '...', fileType: 'docx' }) with a file that contains tracked changes (revision marks from previous editing sessions)
3.Click "Yes" on the confirmation dialog ("All tracked changes will be considered accepted")
4.Editor crashes with a TypeError

Version 9.3.1:

TypeError: Cannot read properties of undefined (reading 'da')
at sj (sdk-all.js:9247:115)
at Oa.D9c (sdk-all.js:12899:322)
at A.compare (sdk-all.js:12863)

Version 9.4.0.1:

TypeError: Cannot read properties of undefined (reading 'Split2')
at CRunCollector.splitCurrentRun (sdk-all.js:628537:15)
at CLabelChange.apply (sdk-all.js:624316:30)
at resolveTypesWithPartner (sdk-all.js:624132:12)
at CDocumentComparison.applyChangesToParagraph (sdk-all.js:626856:4)
at CDocumentComparison.compare (sdk-all.js:626734:13)

Root Cause Analysis

In CRunCollector.splitCurrentRun:

CRunCollector.prototype.splitCurrentRun = function (bAfter) {
    const oRun = this.getRun();
    return oRun.Split2(...); // oRun is undefined
};

CRunCollector.prototype.getRun = function () {
    const oContent = this.parent.Content;
    return oContent[this.runIndex]; // returns undefined
};

When the revised document contains tracked changes (<w:ins>/<w:del>), the comparison algorithm (CDocumentComparison) processes the document tree after the tracked changes have been "accepted" internally. This creates a mismatch between this.runIndex and the actual Content array length — the index points beyond the array bounds because the acceptance of tracked changes modified the content structure without updating the CRunCollector's index references.

Suggested Fix

In CDocumentComparison.compare() or CompareBinary(), before running the comparison algorithm, the revised document's tracked changes should be fully resolved (accepted/rejected) and the document model should be rebuilt/re-indexed. Alternatively, CRunCollector.getRun() should include a bounds check:

CRunCollector.prototype.getRun = function () {
    const oContent = this.parent.Content;
    if (this.runIndex >= oContent.length) return null;
    return oContent[this.runIndex];
};

CRunCollector.prototype.splitCurrentRun = function (bAfter) {
    const oRun = this.getRun();
    if (!oRun) return null;
    return oRun.Split2(bAfter ? this.runElementIndex + 1 : this.runElementIndex, this.parent, this.runIndex);
};

Workaround

Pre-process the revised file to strip all tracked changes from the docx XML before passing it to setRevisedFile():

Remove <w:del> elements entirely
Unwrap <w:ins> elements (keep inner content)
Remove *Change elements (<w:rPrChange>, <w:pPrChange>, etc.)

Environment

Document Server: 9.3.1 and 9.4.0.1
Browser: Chrome 148
OS: Windows 11

[regent112]

Hello @IuLeon. The error couldn't be reproduced using the steps provided. Can you send me a sample file?

[IuLeon]

edit_file_1.docx
source_file.docx

The comparison files are source_file.docx and edit_file_1.docx.
Upload source_file.docx first, then select edit_file_1.docx as the comparison file. This reproduces the error in both version 9.3.1 and 9.4.0.1.

[regent112]

Thank you very much for your feedback. Bug #81783 has been reported.