Slint 1.18.1 still uses patched Parley 0.11.1. Blitz 0.3.0-beta.4 uses upstream Parley 0.12.0, which already includes Parley #811, which fixes #744. Plain digits, #, *, ©, and ® have the Unicode Emoji property, but default to text presentation. Previously they entered emoji fallback before script fallback when an email requested an unavailable font (Mail #16/#23).

Sources and adaptation

crates/parley: published 0.11.1, revision eea3503dd6cf17130cbb07348e0ff2c918300e94, plus 0001-emoji-presentation.patch.
crates/parley_emoji: the sequence detector, README, and MIT license copied unchanged from PR #811 at 479e1980aeca0db63999cedce1b6f31332fe0a7b. Its standalone Cargo manifest is kept alongside this patch queue.
The shaping integration follows that revision's CharCluster::fill. It reads the existing ICU property tables directly for emoji-capable clusters, avoiding a second fork of the generated parley_data tables and changes to 0.11's analysis metadata. The detector does not allocate.
Font-selection presentation is separate from character/editor metadata. Sender-specified fonts retain their existing precedence. No generic font is inserted into CSS family stacks.
The crate's published builder tests depend on omitted parley_dev and font fixtures. That module and unused oxipng test dependency are disabled; its self-contained analysis tests and our presentation tests run in CI. Application tests cover font selection and actual CPU/GPU output with a deterministic bitmap emoji font.

This retains the upstream detector's documented limitations for malformed sequences, mixed presentation within a grapheme, and legacy modifier sequences with intervening VS16. It does not add bitmap emoji support to the CPU painter.

Verification and upgrades

python3 scripts/verify-parley.py
cargo test --manifest-path crates/parley/Cargo.toml --lib --locked --target-dir target/parley-tests
cargo test -p flectar-mail --lib renderer::regression --locked
# On a host with a WGPU adapter:
cargo test -p flectar-mail --lib issue_23_gpu --locked -- --ignored

The verifier downloads checksum-pinned sources into a temporary directory, applies the patch, and compares every file to both checked-in crates. It also checks desktop/Android patch wiring and the packaged MIT notice.

When Slint also adopts a release with the presentation fix, remove this backport, both vendored crates, their manifest patches, and the verification step; update both lockfiles and rerun the application regressions. Keep the regression fixtures. Do not restore the removed Blitz CSS fallback workaround.