[pierre-b]

Closes #443.

What it does

Every email now goes out with a text/plain alternative next to its HTML, generated at send time from the final HTML (after link tracking), so the text links are tracked or direct exactly as decided for the recipient. No schema change, no new environment variable, nothing stored in the queue payload.

• Converter pkg/plaintext (FromHTML, on golang.org/x/net/html, no new dependency): paragraphs, headings, lists (including the <li><p> markup of the visual editor and <ol start>), blockquotes, pre, hr; links as label (url), mailto:/tel: targets, linked images by their alt; head, scripts, styles, form controls, hidden elements and the inbox preheader are skipped; invisible padding characters removed; a space always separates a URL from the next word, and only ASCII punctuation stays attached after a URL. Returns "" when the HTML holds nothing to read, and the email is then sent as HTML only.
• Send path: SendEmailProviderRequest.TextContent, filled in EmailService.SendEmail when the caller gives none. Providers: SMTP (multipart/alternative, text first), Amazon SES simple (Body.Text) and raw MIME (mixed > alternative { text, related { html, inline } } + attachments), SendGrid (text/plain first, as required), Mailgun form and multipart (text), Postmark (TextBody), Mailjet (TextPart), SparkPost (content.text). Each field is absent when there is no text.
• Preview: templates.compile returns text (only when called by the preview endpoint: IncludeText is json:"-", so send-time compiles do not convert twice). Console: a Text version mode next to Edit and Preview in the visual editor, a Text version tab in the MJML editor and in the template preview drawer. The editor toolbar labels are now translated; new strings translated in the 8 catalogs.
• Version 43.2 (dev released 43.1 meanwhile and is merged in), changelog entry, SDK bundle rebuilt, OpenAPI updated, plan in plans/feat-plain-text-alternative-plan.md. Docs: Document the plain-text version of emails docs#27.

Tests

• Unit: converter table tests, invalid UTF-8, fixture, fuzz (FuzzFromHTML, script never leaks, at most one blank line, valid UTF-8), benchmark; MIME tree of every SMTP and SES shape; exact body of each HTTP provider with and without text; SendEmail generation; compile (IncludeText, web channel, errors, URL-set equality with the HTML hrefs with tracking on and off, golden template); handler.
• Integration (tests/integration/plain_text_alternative_e2e_test.go, Mailpit raw MIME): transactional and broadcast emails are multipart/alternative with text first, the text links to exactly the URLs of the HTML, tracked for a consenting contact and direct for one who refused click tracking, List-Unsubscribe kept, templates.compile returns the text.
• Locally green: go test -race ./internal/... ./pkg/..., full make test-integration (on 11faeff), then after the dev merge the plain-text, List-Unsubscribe and inline-CID e2e tests, cd console && npx vitest run (173 files), tsc -b, eslint on touched files.

Review status — in progress

Plan reviewed before implementation; code reviewed three times (whole PR, then each correction). The last blocking finding (typographic closing quotes ”, ’, » read by autolinkers as part of a URL) is fixed in 4133bc2 with a test for a bare URL followed by each closer. The fix and the dev merge (3baffee) are under review.

Known, not handled

• With click tracking on, a labelled social element is written on two lines (the icon's tracked URL, then Facebook (…)): the two links get different tokens, and nothing in the HTML says they lead to the same place. An earlier attempt to drop the icon lost destinations in other layouts and was removed.
• Nested anchors whose outer label starts with a URL keep only the outer href; a bare URL line can be dropped if the next line ends with the same URL in brackets inside another URL (contrived).
• A list item starting with <pre> or a nested list misplaces its marker; start="3px" numbers from 1; URLs inside <pre> are not separated from the following text.
• mailto: with only a query (mailto:?subject=…) gives an empty target.
• pkg/mailer system emails put their text part last; the API field email.text of a template is still unused (custom text is a later PR).
• The MJML editor's text tab shows "Compiling..." with an empty source and keeps the last text when the source is cleared.
• Provider-side link tracking (SendGrid, Mailgun, Postmark) rewrites text links too, as for the HTML.

[codecov]

Codecov Report

❌ Patch coverage is 92.33333% with 23 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.77%. Comparing base (f7699b8) to head (3baffee).

Files with missing lines	Patch %	Lines
internal/service/ses_service.go	65.00%	7 Missing and 7 partials ⚠️
pkg/plaintext/plaintext.go	96.98%	4 Missing and 3 partials ⚠️
internal/service/mailgun_service.go	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #504      +/-   ##
==========================================
+ Coverage   88.73%   88.77%   +0.03%     
==========================================
  Files         365      366       +1     
  Lines       71231    71512     +281     
==========================================
+ Hits        63210    63484     +274     
+ Misses       5397     5396       -1     
- Partials     2624     2632       +8     

Flag	Coverage Δ
unit	88.77% <92.33%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.