[vitormattos]

Problem

Fixes #9425.

An email-identified signer whose address belongs to an existing Nextcloud account could receive neither the signing invitation nor an in-app notification: the invitation-mail path consulted an account's opt-out despite the recipient being explicitly identified via email. In-app and activity invitations are restricted to account signers.

Behavior and architecture

• Invitation/reminder: send by email to an explicitly email-identified signer regardless of whether that address belongs to a Nextcloud account; never turn the email address into a Nextcloud UID.
• Account signer: resolve email through the selected account and check the actual account UID for preference decisions, including shared-email accounts.
• Cancellation: preserve the existing unique-email-account preference semantics for email-identified recipients. They must not receive previously suppressed cancellation messages. For account-identified recipients, preferences are checked by selected UID.
• Continue skipping deleted identities, unresolved accounts and empty addresses. Preserve signed-file email handling, failure isolation and mail-history semantics.
• Remove unused listener dependencies; only the private mail-recipient resolution/notification rule is shared. No new public service, API or authentication change.

Regression tests and testability

MailNotifyListenerTest drives the public handle(Event) method and inspects emitted NotificationMessage objects rather than invoking MailChannel inside the listener tests. Readable small event factories remove repeated internal setup, and preference fixtures use UID-sensitive returns to assert observable delivery outcomes instead of internal call counts.

Covered: existing GUID-style UID vs email; external email signer; observer; reminder vs first invitation; account enable/disable preference; shared email; deleted/unresolved accounts; empty and unsupported identifiers; cancellation (unique linked account enabled/disabled, external, shared); owner-signed messages and envelope child suppression.

NotificationChannelsTest independently verifies mapping of first invitations, reminders, signed-file and cancellation messages to the expected MailService calls. Observer validation links are covered in the existing MailServiceTest.

Validation

• Code and tests are against main (original base b02d0b82e3abe346085c8bfe059e7ca4bf8f6bfd). The next main commit only updates Transifex translations.
• The original minimal fix passed all 21 CI workflows. The larger architecture refactor had successfully completed 18/21 workflows without failures when reviewed, but this is not evidence for the later corrective commits.
• CI failure diagnosis: all four PHPUnit database workflows failed in testExternalEmailSignerReceivesCancellation because IUserManager::getByEmail() was not stubbed for an external address and returned null in PHPUnit; count(null) caused a TypeError. Fixed by explicitly configuring [] for the missing account, without altering production behavior.
• Latest head: f7d25426f44d9786f43ce1b3d46a365ef20d8320. All four PHPUnit database workflows (SQLite, MySQL, MariaDB, PostgreSQL) passed on this head. At the last verification, 19/21 workflows had passed; Playwright and Behat PostgreSQL were still running. Do not merge until final checks are verified.
• All commits DCO sign-off and cryptographic signing verified.
• No live NC35/LibreSign 15.0.12 reproduction or test SMTP delivery was executed; the CI tests target the current main contract.

No automatic merge requested.

[github-actions]

Code Metrics Report

	main (b02d0b8)	#9429 (a263225)	+/-
Coverage	76.1%	76.2%	+0.0%
Test Execution Time	1s	2s	+1s

Details

  |                     | main (b02d0b8) | #9429 (a263225) |  +/-  |
  |---------------------|----------------|-----------------|-------|
+ | Coverage            |          76.1% |           76.2% | +0.0% |
  |   Files             |            500 |             500 |     0 |
  |   Lines             |          28578 |           28576 |    -2 |
+ |   Covered           |          21776 |           21779 |    +3 |
- | Test Execution Time |             1s |              2s |   +1s |

Code coverage of files in pull request scope (82.0% → 86.7%, patch 100.0%)

Files	Coverage	+/-	Patch Coverage	Status
lib/Listener/MailNotifyListener.php	86.7%	+4.7%	100.0%	modified

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Reported by octocov

[vitormattos]

/backport to stable35

[vitormattos]

/backport to stable34

[vitormattos]

/backport to stable33