Make the HTML report a single self-contained index.html - #1245
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The HTML formatter previously wrote index.html plus five sibling files (coverage_data.js, application.js, application.css, and three favicon PNGs). The compiled template now inlines the viewer's JavaScript and CSS at build time (rake assets:compile), and the formatter substitutes the coverage JSON at a marker in the template at report time, so the whole report is one file. coverage.json is still written alongside as the sanctioned data artifact. A single file can be mailed, copied anywhere, or uploaded as a non-zipped GitHub Actions run artifact (actions/upload-artifact with archive: false only supports single files) and viewed directly from the run page. It also makes report updates atomic. A reader can no longer catch index.html and coverage_data.js from different runs because the report is replaced in one rename. Every "<" in the embedded payload is escaped as \u003c (valid JSON, since "<" can only occur inside strings), so source text containing "</script>" or "<!--" cannot terminate the surrounding script element. The asset build refuses to inline a bundle containing such sequences. The embedded payload is serialized compactly. Pretty printing puts every element of every per-line coverage array on its own indented line, which makes the report roughly a third larger (simplecov's own dogfood report is 647 KB compact against 947 KB pretty). The sibling coverage.json stays pretty-printed for human readers. The asset build also renames the stylesheet's custom properties to short aliases after minification. The descriptive names repeat at every use and cost about 3 KB of the compiled template. Properties that JavaScript reads or writes by name (--bar-sizer-width and the band colours) are exempt and keep their names. The favicon (a solid square in the overall coverage band's colour) is drawn by the viewer on a canvas from the live --green/--red/--yellow palette values instead of shipping as fixed PNGs, so it matches the report's colours exactly and follows the light/dark theme, including the in-page toggle and OS preference changes. The pre-1.0 simplecov-html formatter offered inline assets behind the SIMPLECOV_INLINE_ASSETS environment variable. The 1.0 client-side rendering rewrite dropped that mode. This restores single-file reports as the default and only mode, with no flag or environment variable. Resolves #1241.
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The HTML formatter previously wrote index.html plus five sibling files (coverage_data.js, application.js, application.css, and three favicon PNGs). This PR makes the report a single file. The asset build (
rake assets:compile) now inlines the viewer's JavaScript and CSS into the compiled template and converts the favicon PNGs to data URIs, and at report time the formatter substitutes the coverage JSON at a marker in the template and writes one index.html. coverage.json is still written alongside as the sanctioned data artifact for downstream tools.A single file can be mailed, copied anywhere, or uploaded as a non-zipped GitHub Actions run artifact (actions/upload-artifact with
archive: falseonly supports single files) and viewed directly from the run page. It also makes report updates atomic. A reader can no longer catch index.html and coverage_data.js from different runs, because the report is replaced in one rename.Embedding the data is done safely. Every "<" in the embedded payload is escaped as \u003c, which is valid JSON since "<" can only occur inside strings, so source text containing "</script>" or "<!--" cannot terminate the surrounding script element. The asset build refuses to inline a compiled bundle containing such sequences, rather than emit a template that would truncate at render time.
The pre-1.0 simplecov-html formatter offered inline assets behind the
SIMPLECOV_INLINE_ASSETSenvironment variable, and the 1.0 client-side rendering rewrite dropped that mode. This restores single-file reports as the default and only mode, with no flag or environment variable.