From fc78d52c992b5f5d6d7a154a9b90a9341f558e3c Mon Sep 17 00:00:00 2001
From: GeoSot <geo.sotis@gmail.com>
Date: Tue, 12 Oct 2021 02:22:36 +0300
Subject: [PATCH] modal: don't add margin & padding when sticky is not full
 width (Backports #30621)

---
 js/src/modal.js        | 45 ++++++++++++++++++++----------------------
 js/tests/unit/modal.js | 34 +++++++++++++++++++++++++++++--
 2 files changed, 53 insertions(+), 26 deletions(-)

diff --git a/js/src/modal.js b/js/src/modal.js
index a23bfc1ba6d0..d56424b82f65 100644
--- a/js/src/modal.js
+++ b/js/src/modal.js
@@ -477,40 +477,37 @@ class Modal {
 
   _setScrollbar() {
     if (this._isBodyOverflowing) {
-      // Note: DOMNode.style.paddingRight returns the actual value or '' if not set
-      //   while $(DOMNode).css('padding-right') returns the calculated value or 0 if not set
-      const fixedContent = [].slice.call(document.querySelectorAll(SELECTOR_FIXED_CONTENT))
-      const stickyContent = [].slice.call(document.querySelectorAll(SELECTOR_STICKY_CONTENT))
-
       // Adjust fixed content padding
-      $(fixedContent).each((index, element) => {
-        const actualPadding = element.style.paddingRight
-        const calculatedPadding = $(element).css('padding-right')
-        $(element)
-          .data('padding-right', actualPadding)
-          .css('padding-right', `${parseFloat(calculatedPadding) + this._scrollbarWidth}px`)
-      })
+      this._setElementAttributes(SELECTOR_FIXED_CONTENT, 'paddingRight', 'padding-right', true)
 
       // Adjust sticky content margin
-      $(stickyContent).each((index, element) => {
-        const actualMargin = element.style.marginRight
-        const calculatedMargin = $(element).css('margin-right')
-        $(element)
-          .data('margin-right', actualMargin)
-          .css('margin-right', `${parseFloat(calculatedMargin) - this._scrollbarWidth}px`)
-      })
+      this._setElementAttributes(SELECTOR_STICKY_CONTENT, 'marginRight', 'margin-right', false)
 
       // Adjust body padding
-      const actualPadding = document.body.style.paddingRight
-      const calculatedPadding = $(document.body).css('padding-right')
-      $(document.body)
-        .data('padding-right', actualPadding)
-        .css('padding-right', `${parseFloat(calculatedPadding) + this._scrollbarWidth}px`)
+      this._setElementAttributes('body', 'paddingRight', 'padding-right', true)
     }
 
     $(document.body).addClass(CLASS_NAME_OPEN)
   }
 
+  _setElementAttributes(selector, styleProp, jqCssProperty, add) {
+    // Note: DOMNode.style.paddingRight returns the actual value or '' if not set
+    //   while $(DOMNode).css('padding-right') returns the calculated value or 0 if not set
+    const elements = [].slice.call(document.querySelectorAll(selector))
+    $(elements).each((index, el) => {
+      if (el !== document.body && window.innerWidth > el.clientWidth + this._scrollbarWidth) {
+        return
+      }
+
+      const actualValue = el.style[styleProp]
+      const calculatedValue = $(el).css(jqCssProperty)
+      const newValue = parseFloat(calculatedValue) + ((add ? 1 : -1) * this._scrollbarWidth)
+      $(el)
+        .data(jqCssProperty, actualValue)
+        .css(jqCssProperty, `${newValue}px`)
+    })
+  }
+
   _resetScrollbar() {
     // Restore fixed content padding
     const fixedContent = [].slice.call(document.querySelectorAll(SELECTOR_FIXED_CONTENT))
diff --git a/js/tests/unit/modal.js b/js/tests/unit/modal.js
index 028ed5490ba1..683f8037ede0 100644
--- a/js/tests/unit/modal.js
+++ b/js/tests/unit/modal.js
@@ -162,6 +162,32 @@ $(function () {
       .bootstrapModal('toggle')
   })
 
+  QUnit.test('should not adjust the inline margin and padding of sticky and fixed elements when element do not have full width', function (assert) {
+    assert.expect(2)
+    var done = assert.async()
+    var content = [
+      '<div class="sticky-top" style="margin-right: 0; padding-right: 0; width: calc(100vw - 50%)"></div>',
+      '<div class="modal"><div class="modal-dialog"></div></div>'
+    ].join('')
+    $(content).appendTo('#qunit-fixture')
+
+    var stickyTopEl = $('.sticky-top')
+    var originalMargin = stickyTopEl.css('margin-right')
+    var originalPadding = stickyTopEl.css('padding-right')
+
+    var modal = $('.modal')
+    modal.on('shown.bs.modal', function () {
+      var currentMargin = stickyTopEl.css('margin-right')
+      var currentPadding = stickyTopEl.css('padding-right')
+
+      assert.strictEqual(currentMargin, originalMargin, 'sticky element\'s margin should not be adjusted while opening')
+      assert.strictEqual(currentPadding, originalPadding, 'sticky element\'s padding should not be adjusted while opening')
+      done()
+    })
+
+    modal.bootstrapModal('show')
+  })
+
   QUnit.test('should remove from dom when click [data-dismiss="modal"]', function (assert) {
     assert.expect(3)
     var done = assert.async()
@@ -529,7 +555,9 @@ $(function () {
         done()
       })
       .on('shown.bs.modal', function () {
-        assert.strictEqual($element.data('padding-right'), originalPadding, 'original fixed element padding should be stored in data-padding-right')
+        var dataPaddingRight = $element.data('padding-right')
+        var isCorrect = (dataPaddingRight === originalPadding || typeof dataPaddingRight === 'undefined')
+        assert.true(isCorrect, 'original fixed element padding should be stored in data-padding-right')
         $(this).bootstrapModal('hide')
       })
       .bootstrapModal('show')
@@ -571,7 +599,9 @@ $(function () {
         done()
       })
       .on('shown.bs.modal', function () {
-        assert.strictEqual($element.data('margin-right'), originalPadding, 'original sticky element margin should be stored in data-margin-right')
+        var dataMarginRight = $element.data('margin-right')
+        var isCorrect = (dataMarginRight === originalPadding || typeof dataMarginRight === 'undefined')
+        assert.true(isCorrect, 'original sticky element margin should be stored in data-margin-right')
         $(this).bootstrapModal('hide')
       })
       .bootstrapModal('show')