resolve #1972, allowing add-ons at beginning and end of input-prepend/append

docs/assets/css/bootstrap.css

@@ -1013,7 +1013,6 @@ select:focus:required:invalid:focus {
   width: auto;
   min-width: 16px;
   height: 18px;
-  margin-right: -1px;
   padding: 4px 5px;
   font-weight: normal;
   line-height: 18px;
@@ -1031,6 +1030,9 @@ select:focus:required:invalid:focus {
   background-color: #a9dba9;
   border-color: #46a546;
 }
+.input-prepend .add-on {
+  margin-right: -1px;
+}
 .input-append input,
 .input-append select .uneditable-input {
   -webkit-border-radius: 3px 0 0 3px;
@@ -1042,7 +1044,25 @@ select:focus:required:invalid:focus {
   border-right-color: #ccc;
 }
 .input-append .add-on {
-  margin-right: 0;
+  margin-left: -1px;
+  -webkit-border-radius: 0 3px 3px 0;
+  -moz-border-radius: 0 3px 3px 0;
+  border-radius: 0 3px 3px 0;
+}
+.input-prepend.input-append input,
+.input-prepend.input-append select,
+.input-prepend.input-append .uneditable-input {
+  -webkit-border-radius: 0;
+  -moz-border-radius: 0;
+  border-radius: 0;
+}
+.input-prepend.input-append .add-on:first-child {
+  margin-right: -1px;
+  -webkit-border-radius: 3px 0 0 3px;
+  -moz-border-radius: 3px 0 0 3px;
+  border-radius: 3px 0 0 3px;
+}
+.input-prepend.input-append .add-on:last-child {
   margin-left: -1px;
   -webkit-border-radius: 0 3px 3px 0;
   -moz-border-radius: 0 3px 3px 0;

less/forms.less

@@ -379,7 +379,6 @@ select:focus:required:invalid {
     width: auto;
     min-width: 16px;
     height: @baseLineHeight;
-    margin-right: -1px;
     padding: 4px 5px;
     font-weight: normal;
     line-height: @baseLineHeight;
@@ -395,6 +394,11 @@ select:focus:required:invalid {
     border-color: @green;
   }
 }
+.input-prepend {
+  .add-on {
+    margin-right: -1px;
+  }
+}
 .input-append {
   input,
   select
@@ -406,7 +410,22 @@ select:focus:required:invalid {
     border-right-color: #ccc;
   }
   .add-on {
-    margin-right: 0;
+    margin-left: -1px;
+    .border-radius(0 3px 3px 0);
+  }
+}
+// Remove all border-radius for inputs with both prepend and append
+.input-prepend.input-append {
+  input,
+  select,
+  .uneditable-input {
+    .border-radius(0);
+  }
+  .add-on:first-child {
+    margin-right: -1px;
+    .border-radius(3px 0 0 3px);
+  }
+  .add-on:last-child {
     margin-left: -1px;
     .border-radius(0 3px 3px 0);
   }