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Typsastra v0.8.0 Unicode PDF Reliability Implementation Plan

Objective

Ship v0.8.0 as a stabilization and integration milestone for reliable Unicode PDF export and standalone PDF interoperability. The release productizes the work added after v0.7.0 without introducing another large editor, preview-root, or font-management architecture.

The release has one end-to-end contract:

portable Typst source
  -> explicit PDF export
  -> reproducible compiler identity
  -> valid Unicode PDF
  -> standalone PDF viewing
  -> search, selection, links, outline, and clipboard interoperability

The optional Enhanced Unicode Engine remains experimental and opt-in. It is used only for explicit PDF export. Tinymist remains authoritative for live preview, diagnostics, autocomplete, formatting, and source synchronization.

Scope boundaries

v0.8.0 does not include:

  • portable Full Document and Active File preview modes;
  • a broader font manager or project font-dependency dashboard;
  • first-class right-to-left editor behavior;
  • a broad autocomplete snippet library;
  • original-image replacement or selective image-reference rewriting;
  • redesigned document-language inheritance; or
  • an SVG live-preview architecture.

Critical regressions in existing features remain in scope. Missing-font and font-processing failures must be actionable, but v0.8.0 does not create a new font ownership or packaging model.

Existing implementation baseline

The following work landed after v0.7.0 and must be treated as an integrated release candidate rather than independent experiments:

  • managed, checksummed Enhanced Unicode Engine installation;
  • Enhanced Unicode Engine v0.4.0 with the compact logical-font v4 serializer;
  • reproducible source and binary release metadata;
  • PDF 1.4 through 2.0, PDF/A, and PDF/UA release validation;
  • bundled PDFium rendering for directly opened PDFs;
  • logical Unicode search and semantic text selection;
  • selection context menus, PDF links, and document outlines;
  • plain and formatted clipboard reconstruction;
  • preservation of whitespace, boxes, and tables in formatted copy;
  • search-marker, zoom-overlay, docking, and viewport fixes; and
  • grapheme-aware desktop text controls.

Workstream V08-E: Enhanced Unicode export productization

Contract

  • Installation is explicit and uses the pinned release manifest for the current platform.
  • Archive byte length and SHA-256 are verified before installation.
  • The installed executable is validated before it is selected and before each export.
  • Enhanced export never replaces Tinymist for live services.
  • Failure never silently falls back to ordinary export.
  • Disabling the engine restores the ordinary Tinymist export path.
  • The user can identify the engine version used for an export.

Tasks

  • [ ] V08-E.1 Audit managed installation and recovery. Cover first install, cancellation, retry, interrupted download, checksum mismatch, stale temporary files, missing installed files, and an executable that no longer validates.
  • [ ] V08-E.2 Add explicit repair behavior. Let a user reinstall the pinned engine after validation failure without manually editing settings or cache directories.
  • [ ] V08-E.3 Report export provenance. Include ordinary Tinymist or Enhanced Unicode Engine plus its validated version in success and diagnostic details.
  • [ ] V08-E.4 Make failures actionable. Distinguish installation, validation, unsupported-version, source, font-processing, cancellation, and destination-write failures.
  • [ ] V08-E.5 Make final output transactional. Compile to a temporary output, verify a non-empty PDF, and atomically replace the requested destination so a failed export cannot destroy a previous valid PDF.
  • [ ] V08-E.6 Preserve explicit consent. Keep the engine default-off and clearly labeled experimental for v0.8.0.
  • [ ] V08-E.7 Lock regressions. Compile the wide repeated-fill fixture and the multilingual extraction fixture with every released engine package.

Workstream V08-P: Standalone PDF reliability

Contract

A directly opened PDF uses the bundled PDFium path. Its page rendering, text extraction, semantic selection geometry, search, links, and outline belong to one generation-scoped document. PDF.js remains the live Typst-preview renderer.

Tasks

  • [ ] V08-P.1 Qualify document replacement. Cancel stale opens, searches, renders, overlays, outlines, and link state when another PDF replaces the document.
  • [ ] V08-P.2 Qualify viewport lifecycle. Cover initial open, page jumps, continuous scrolling, fractional zoom, resize, dock, undock, and redock.
  • [ ] V08-P.3 Qualify navigation. Cover internal destinations, external links, malformed destinations, outline expansion, and repeated page jumps.
  • [ ] V08-P.4 Qualify search. Cover Unicode queries, mixed scripts, rapid query replacement, next/previous wraparound, virtualized pages, and cleared state after project replacement.
  • [ ] V08-P.5 Qualify selection. Cover drag direction, multi-line and multi-page ranges, combining marks, grapheme boundaries, zoom, and page virtualization.
  • [ ] V08-P.6 Qualify hostile and unsupported input. Cover malformed, password-protected, empty, oversized, and unsupported PDFs without exposing a stale prior document as the successful result.
  • [ ] V08-P.7 Measure native resources. Record first-page latency, open/close cycles, rendered-page residency, and settled PDFium/WebView process memory on supported desktop platforms.

Workstream V08-C: Unicode and clipboard interoperability

Contract

Logical extraction, search matching, visual selection geometry, plain-text copy, and formatted copy are related but independently tested capabilities. A pass in one viewer or clipboard target is not proof of universal compatibility.

Tasks

  • [ ] V08-C.1 Expand the fixture corpus. Retain directly authored Latin, combining, Khmer, Arabic, Devanagari, Thai, Lao, mixed-script, punctuation, table, multi-font, long-line, and repeated-fill cases.
  • [ ] V08-C.2 Keep logical and visual checks separate. Continue reporting exact text, whitespace-insensitive text, unexpected controls, finite geometry, and in-page geometry independently.
  • [ ] V08-C.3 Qualify plain copy. Paste into a plain-text editor and compare exact Unicode, line structure, whitespace, and bidi ordering.
  • [ ] V08-C.4 Qualify formatted copy. Verify paragraphs, boxes, and tables in representative rich-text and office applications without weakening the plain text fallback.
  • [ ] V08-C.5 Record viewer interoperability. Test available versions of Acrobat Reader, Edge, Chrome, Firefox, and macOS Preview and record rather than infer their results.
  • [ ] V08-C.6 Resolve or disclose mixed-direction limitations. Fix the known PDFium mixed Latin/Arabic ordering issue if it has a bounded PDF adapter solution. Do not pull the full RTL editor milestone into v0.8.0.

Workstream V08-R: Reliability, performance, and release integration

Tasks

  • [ ] V08-R.1 Run universal validation. Keep frontend, Rust, Khmer, Lao, documentation, examples, and production builds passing.
  • [ ] V08-R.2 Publish measured PDFium gates. Establish values from Windows and Linux measurements instead of copying PDF.js assumptions.
  • [ ] V08-R.3 Test export isolation. Enhanced export must not mutate live preview ownership, Tinymist state, diagnostics, source maps, or unsaved text.
  • [ ] V08-R.4 Test project workflows. Verify Unicode paths, imported projects, restored workspaces, direct PDFs, and exported PDFs across project replacement.
  • [ ] V08-R.5 Update current documentation. Explain the three compiler/viewer roles, managed engine behavior, known limitations, recovery, and test scope.
  • [ ] V08-R.6 Run a bug-fix freeze. After planned work is complete, accept only blocker, regression, documentation, packaging, and release-qualification changes until v0.8.0 ships.

Proposed performance measurements

The following are measurement targets until v0.8.0 qualification publishes an approved platform baseline. They must not be presented as passed before real release builds are measured.

Operation Initial target
First visible page for an ordinary standalone PDF 1,000 ms
Zoom overlay refresh after settled zoom 750 ms
Commit of stale search results Never
Commit of stale page or selection overlays Never
Native memory growth across repeated open/close Bounded and documented
Resident rendered pages Bounded and documented

Implementation phases

Phase 0 — contracts and regression fixtures

  • Establish this plan and the release qualification record.
  • Add the wide repeated-fill engine fixture.
  • Correct stale roadmap and managed-installation documentation.

Phase 1 — bug fixing and lifecycle hardening

  • Fix known export, PDFium, selection, search, clipboard, and docking defects.
  • Add focused tests with each fix.

Phase 2 — recovery and user-facing diagnostics

  • Complete install repair, export provenance, transactional output, and actionable failure reporting.

Phase 3 — platform qualification

  • Run automated suites and manual viewer/clipboard matrices.
  • Measure Windows and Linux release builds; qualify macOS where available or state its narrower evidence explicitly.

Phase 4 — release freeze

  • Update release notes and compatibility disclosures.
  • Freeze features and resolve all blocker-severity regressions.
  • Complete the v0.8.0 release qualification checklist.

Release gate

v0.8.0 is eligible for release only when:

  • every supported application build passes the universal validation suite;
  • every released Enhanced Unicode Engine package compiles the multilingual, wide repeated-fill, and PDF-standards fixtures;
  • every claimed PDF/A and PDF/UA profile passes the pinned validator;
  • failed or cancelled export cannot replace a valid destination PDF;
  • no enhanced-engine failure silently falls back to another compiler;
  • standalone PDF replacement cannot commit stale search, selection, outline, link, page, or overlay state;
  • native resource behavior is measured and documented;
  • known mixed-direction and viewer-specific limitations are fixed or disclosed;
  • existing Tinymist preview/export, Markdown, project interchange, Khmer, Lao, and grapheme editing regressions pass; and
  • no known data-loss, security, crash, or blocker-severity export/PDF defect remains.

The tracked evidence belongs in V0_8_0_RELEASE_QUALIFICATION.md.