fix(scripts): Reorder bundle so bslib wins cascade ties against shiny.scss#2254
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elnelson575 wants to merge 1 commit into
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fix(scripts): Reorder bundle so bslib wins cascade ties against shiny.scss#2254elnelson575 wants to merge 1 commit into
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….scss `bs_full_theme()` in `scripts/_functions_sass.R` previously called `bs_bundle(theme, bslib = ..., shiny = ..., ...)`. bslib's `bs3compat` SCSS is baked into the `theme` argument, and `bs_bundle()` always stacks named layers on top of `theme`. This put bslib's overrides *before* R-shiny's `shiny.scss` rules in the compiled CSS, so any same-specificity tie went to shiny.scss by source order — the opposite of an R-shiny + bslib app, where R-shiny's `shiny.css` is loaded as its own `<link>` before bslib's bundle. The visible symptom: bslib PR #1308 (which lifts the specificity of the BS5 radio/checkbox label-margin rule to `.shiny-input-container .shiny-input-{kind}`) fixed vertical groups in py-shiny but inline groups still got the `-1px` from shiny.scss's `.shiny-input-{kind}.shiny-input-container-inline` rule, which ties at 0-3-1 and was emitted later in the file. Fix: drop down from `bs_bundle()` to `sass::sass_bundle()` so the theme can appear after a user layer, list `shiny` first and `theme` second, then reapply `class(theme)` to keep the bs_theme identity (mirrors `bs_bundle()`'s own implementation). The only same-specificity, same-element conflict between bs3compat and shiny.scss in BS5 mode is the radio/checkbox label-margin rule; no other styles change behavior under the reorder. Depends on rstudio/bslib#1308 for the visible fix.
This was referenced May 21, 2026
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Summary
Reorder layers in
bs_full_theme()so R-shiny'sshiny.scssemits before bslib's bs3compat in the compiledbootstrap.min.css. This matches the R-shiny + bslib head order and lets bslib's bs3compat overrides win cascade ties.bs_bundle()requiresthemefirst, so drop down tosass::sass_bundle()and reapply thebs_themeclass (mirroringbs_bundle()'s own implementation).Why
Inside py-shiny's combined bundle, bslib bs3compat sat at byte ~278k and shiny.scss at ~360k. Any 0-3-1 ↔ 0-3-1 specificity tie went to shiny.scss by source order — the opposite of R-shiny + bslib, where R-shiny loads its own
shiny.css<link>before bslib's bundle.Concrete symptom: bslib PR rstudio/bslib#1308 lifts the BS5 radio/checkbox label-margin rule to
.shiny-input-container.shiny-input-{kind}(0-3-1). That beat shiny.scss's base-10pxrule (0-2-1) for vertical groups, but tied shiny.scss's.shiny-input-container-inlinerule (0-3-1) and lost on source order for inline groups.Ordering with related PRs
Prerequisite for #2246. The script change must land before
make upgrade-html-depsis re-run, otherwise the regeneratedbootstrap.min.csskeeps the old layer order. Suggested sequence:make upgrade-html-depson chore: Upgrade bslib to 0.11.0 and Bootstrap to 5.3.8, add brite theme #2246's branch, then merge chore: Upgrade bslib to 0.11.0 and Bootstrap to 5.3.8, add brite theme #2246By itself this PR produces no compiled-output diff.
Collateral-damage audit
The only same-specificity, same-element conflict between bs3compat and shiny.scss in BS5 mode is the radio/checkbox label-margin rule. Other bs3compat rules (
.well,.help-text,.glyphicon,.navbar-*,.nav-tabs > li,.dropdown-menu > li,pre.shiny-code,.float-left/right, etc.) target selectors shiny.scss does not style. shiny.scss's.radio/.checkboxusages are prefixed with.qt5(different scope). bs3compat's.radio/.checkboxstyling is wrapped in@if \$bootstrap-version == 4and doesn't compile for BS5.Net effect: only the inline radio/checkbox gap changes, and it changes to the value bslib PR #1308 intended.
Test plan
make upgrade-html-depsand confirm bslib bs3compat rules emit after shiny.scss rules in the regeneratedbootstrap.min.cssui.input_radio_buttons()/ui.input_checkbox_group()share the same label-to-options gap as the vertical variants