Preserves pre-disabled elements with hx-disabled-elt on other element (#3443)

Closes #3437.

Author: StabbarN

src/htmx.js

@@ -3395,8 +3395,10 @@ var htmx = (function() {
     forEach(disabledElts, function(disabledElement) {
       const internalData = getInternalData(disabledElement)
       internalData.requestCount = (internalData.requestCount || 0) + 1
-      disabledElement.setAttribute('disabled', '')
-      disabledElement.setAttribute('data-disabled-by-htmx', '')
+      if (!disabledElement.hasAttribute('disabled')) {
+        disabledElement.setAttribute('disabled', '')
+        disabledElement.setAttribute('data-disabled-by-htmx', '')
+      }
     })
     return disabledElts
   }
@@ -3418,7 +3420,7 @@ var htmx = (function() {
     })
     forEach(disabled, function(disabledElement) {
       const internalData = getInternalData(disabledElement)
-      if (internalData.requestCount === 0) {
+      if (internalData.requestCount === 0 && disabledElement.hasAttribute('data-disabled-by-htmx')) {
         disabledElement.removeAttribute('disabled')
         disabledElement.removeAttribute('data-disabled-by-htmx')
       }

test/attributes/hx-disabled-elt.js

@@ -39,6 +39,18 @@ describe('hx-disabled-elt attribute', function() {
     fieldset.hasAttribute('disabled').should.equal(false)
   })
 
+  it('preserve pre-disabled elements', function() {
+    this.server.respondWith('GET', '/test', 'ok')
+    const b1 = make('<button hx-get="/test" hx-disabled-elt="#b2">Click Me!</button>')
+    const b2 = make('<button id="b2" disabled></button>')
+    b2.hasAttribute('disabled').should.equal(true)
+    b2.hasAttribute('data-disabled-by-htmx').should.equal(false)
+    b1.click()
+    b2.hasAttribute('disabled').should.equal(true)
+    this.server.respond()
+    b2.hasAttribute('disabled').should.equal(true)
+  })
+
   it('multiple requests with same disabled elt are handled properly', function() {
     this.server.respondWith('GET', '/test', 'Clicked!')
     var b1 = make('<button hx-get="/test" hx-disabled-elt="#b3">Click Me!</button>')