Fix missing rels content-type registration causing null MainDocumentPart

[rakeshbabuseva]

Some OOXML generators omit the required <Default Extension="rels" .../> entry from [Content_Types].xml. System.IO.Packaging is strict: without that registration it cannot resolve .rels parts, so the package relationship walk never finds the officeDocument relationship and MainDocumentPart comes back null.

RepairRelsContentType() in StreamPackageFeature detects this deviation before Package.Open and rebuilds the stream with the missing entry injected into [Content_Types].xml. All other ZIP entries are streamed verbatim. The repair is a no-op for well-formed packages. Gated on !NETFRAMEWORK because ZipArchive is not available on net35/net40 and the old System.IO.Packaging on those targets is already lenient.

Fixes: WordprocessingDocument.Open returns null MainDocumentPart when [Content_Types].xml omits Default Extension="rels"

[rakeshbabuseva]

@rakeshbabuseva please read the following Contributor License Agreement(CLA). If you agree with the CLA, please reply with the following information.

@dotnet-policy-service agree [company="{your company}"]

Options:

• (default - no company specified) I have sole ownership of intellectual property rights to my Submissions and I am not making Submissions in the course of work for my employer.

@dotnet-policy-service agree

• (when company given) I am making Submissions in the course of work for my employer (or my employer has intellectual property rights in my Submissions by contract or applicable law). I have permission from my employer to make Submissions and enter into this Agreement on behalf of my employer. By signing below, the defined term “You” includes me and my employer.

@dotnet-policy-service agree company="Microsoft"

Contributor License Agreement

Contribution License Agreement

This Contribution License Agreement ( “Agreement” ) is agreed to by the party signing below ( “You” ), and conveys certain license rights to the .NET Foundation ( “.NET Foundation” ) for Your contributions to .NET Foundation open source projects. This Agreement is effective as of the latest signature date below.

1. Definitions.

“Code” means the computer software code, whether in human-readable or machine-executable form, that is delivered by You to .NET Foundation under this Agreement.

“Project” means any of the projects owned or managed by .NET Foundation and offered under a license approved by the Open Source Initiative (www.opensource.org).

“Submit” is the act of uploading, submitting, transmitting, or distributing code or other content to any Project, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Project for the purpose of discussing and improving that Project, but excluding communication that is conspicuously marked or otherwise designated in writing by You as “Not a Submission.”

“Submission” means the Code and any other copyrightable material Submitted by You, including any associated comments and documentation.

2. Your Submission. You must agree to the terms of this Agreement before making a Submission to any Project. This Agreement covers any and all Submissions that You, now or in the future (except as described in Section 4 below), Submit to any Project.

3. Originality of Work. You represent that each of Your Submissions is entirely Your original work. Should You wish to Submit materials that are not Your original work, You may Submit them separately to the Project if You (a) retain all copyright and license information that was in the materials as you received them, (b) in the description accompanying your Submission, include the phrase "Submission containing materials of a third party:" followed by the names of the third party and any licenses or other restrictions of which You are aware, and (c) follow any other instructions in the Project's written guidelines concerning Submissions.

4. Your Employer. References to “employer” in this Agreement include Your employer or anyone else for whom You are acting in making Your Submission, e.g. as a contractor, vendor, or agent. If Your Submission is made in the course of Your work for an employer or Your employer has intellectual property rights in Your Submission by contract or applicable law, You must secure permission from Your employer to make the Submission before signing this Agreement. In that case, the term “You” in this Agreement will refer to You and the employer collectively. If You change employers in the future and desire to Submit additional Submissions for the new employer, then You agree to sign a new Agreement and secure permission from the new employer before Submitting those Submissions.

5. Licenses.

a. Copyright License. You grant .NET Foundation, and those who receive the Submission directly or indirectly from .NET Foundation, a perpetual, worldwide, non-exclusive, royalty-free, irrevocable license in the Submission to reproduce, prepare derivative works of, publicly display, publicly perform, and distribute the Submission and such derivative works, and to sublicense any or all of the foregoing rights to third parties.

b. Patent License. You grant .NET Foundation, and those who receive the Submission directly or indirectly from .NET Foundation, a perpetual, worldwide, non-exclusive, royalty-free, irrevocable license under Your patent claims that are necessarily infringed by the Submission or the combination of the Submission with the Project to which it was Submitted to make, have made, use, offer to sell, sell and import or otherwise dispose of the Submission alone or with the Project.

c. Other Rights Reserved. Each party reserves all rights not expressly granted in this Agreement. No additional licenses or rights whatsoever (including, without limitation, any implied licenses) are granted by implication, exhaustion, estoppel or otherwise.

6. Representations and Warranties. You represent that You are legally entitled to grant the above licenses. You represent that each of Your Submissions is entirely Your original work (except as You may have disclosed under Section 3 ). You represent that You have secured permission from Your employer to make the Submission in cases where Your Submission is made in the course of Your work for Your employer or Your employer has intellectual property rights in Your Submission by contract or applicable law. If You are signing this Agreement on behalf of Your employer, You represent and warrant that You have the necessary authority to bind the listed employer to the obligations contained in this Agreement. You are not expected to provide support for Your Submission, unless You choose to do so. UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING, AND EXCEPT FOR THE WARRANTIES EXPRESSLY STATED IN SECTIONS 3, 4, AND 6 , THE SUBMISSION PROVIDED UNDER THIS AGREEMENT IS PROVIDED WITHOUT WARRANTY OF ANY KIND, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY OF NONINFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE.

7. Notice to .NET Foundation. You agree to notify .NET Foundation in writing of any facts or circumstances of which You later become aware that would make Your representations in this Agreement inaccurate in any respect.

8. Information about Submissions. You agree that contributions to Projects and information about contributions may be maintained indefinitely and disclosed publicly, including Your name and other information that You submit with Your Submission.

9. Governing Law/Jurisdiction. This Agreement is governed by the laws of the State of Washington, and the parties consent to exclusive jurisdiction and venue in the federal courts sitting in King County, Washington, unless no federal subject matter jurisdiction exists, in which case the parties consent to exclusive jurisdiction and venue in the Superior Court of King County, Washington. The parties waive all defenses of lack of personal jurisdiction and forum non-conveniens.

10. Entire Agreement/Assignment. This Agreement is the entire agreement between the parties, and supersedes any and all prior agreements, understandings or communications, written or oral, between the parties relating to the subject matter hereof. This Agreement may be assigned by .NET Foundation.

.NET Foundation dedicates this Contribution License Agreement to the public domain according to the Creative Commons CC0 1.

@dotnet-policy-service agree

[github-actions]

Test Results

   12 files   -     69     12 suites   - 69   11m 15s ⏱️ - 1h 23m 33s
2 075 tests  -      3  2 072 ✅  -      3  3 💤 ± 0  0 ❌ ±0 
5 476 runs   - 32 721  5 470 ✅  - 32 685  6 💤  - 36  0 ❌ ±0 

Results for commit ece3284. ± Comparison against base commit 00967dc.

This pull request removes 5 and adds 2 tests. Note that renamed tests count towards both.

DocumentFormat.OpenXml.Framework.Tests.HashCodeTests ‑ Comparer
DocumentFormat.OpenXml.Framework.Tests.HashCodeTests ‑ DoubleValue
DocumentFormat.OpenXml.Framework.Tests.HashCodeTests ‑ NoValue
DocumentFormat.OpenXml.Framework.Tests.HashCodeTests ‑ SingleValue
DocumentFormat.OpenXml.Framework.Tests.HashCodeTests ‑ TripleValue

DocumentFormat.OpenXml.Packaging.Tests.OpenXmlPackageTests ‑ Open_MissingRelsContentType_IsIdempotent
DocumentFormat.OpenXml.Packaging.Tests.OpenXmlPackageTests ‑ Open_MissingRelsContentType_MainDocumentPartIsNotNull

♻️ This comment has been updated with latest results.

[mikeebowen]

Thanks for this submission, we should definitely handle this exception. Before final approval, please make a few changes:

• Check for application/vnd.openxmlformats-package.relationships+xml instead of Extension=\"rels\"
• Throw an exception instead of adding the missing element
• Resolve build errors

[mikeebowen]

Technically, the extension is not required to be rels. Instead check for application/vnd.openxmlformats-package.relationships+xml because the content type won't change

[mikeebowen]

Instead of checking for the element and adding it if it's missing, check for ctXml.IndexOf(Marker, StringComparison.Ordinal) == 0 and throw an exception if it is missing. This parallels Office behavior and avoids adding preprocessor statements.

[tomjebo]

hey @rakeshbabuseva,

Thanks very much for this PR. I think this is a good catch. I do have some thoughts on this and please take a look and see what you think.

1. I think to be more correct, and although this is probably hitting corner cases, the code should be testing on "ContentType=\"application/vnd.openxmlformats-package.relationships+xml\"/>" instead of "<Default Extension=\"rels\" "

2. If it does not find any <Default Extension=...> child with application/vnd.openxmlformats-package.relationships+xml content type, it should throw an exception as this likely would mean the integrity of the package is not sound.

3. If it does find such a <Default Extension...> child then the package should be considered ok.

Adding "<Default Extension=\"rels\" " + "ContentType=\"application/vnd.openxmlformats-package.relationships+xml\"/>" would probably be correct most of the time but I think 29500-1 and -2 allow for using another extension and that could mean we're not helping the integrity of the package.

Word does call this out to the user and while it does offer to repair and will use "<Default Extension=\"rels\", Word also would have the extra logic to make sure the actual relationship parts use that extension or change them if they don't. We probably don't want to put all that logic in the SDK.

Finally, I think that throwing the exception would be good since it's apparent that the package integrity is not good and this would allow the Open XML producing app, library or tool to correct the situation rather than mask it.

What do you think? We can discuss further if you'd like.