Filter corruption

[oleggromov]

Hi!
I've found SVGO removing the "id" attribute from elements and "filter" attribute from elements. I think this is tactless behavior.

[deepsweet]

please provide a before/after example because SVGO should not remove these attrs for no reason.

[oleggromov]

before.svg

<?xml version="1.0" encoding="utf-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 513 36">

<defs>
    <filter id="shadow" x="-30%" y="-30%" width="180%" height="180%">
      <feGaussianBlur in="SourceAlpha" stdDeviation="0.25" /> 
      <feOffset dx="1" dy="1" result="offsetblur"/> 
      <feComponentTransfer>
        <feFuncA type="linear" slope="0.4"/>
      </feComponentTransfer>
      <feMerge> 
        <feMergeNode/>
        <feMergeNode in="SourceGraphic"/> 
      </feMerge>
    </filter>
  </defs>

<g filter="url(#shadow)">
    <path fill="#da107e" d="M0.682,9.332C0.654,9.192,0.533,8.682,0.32,7.8C0.107,6.918,0,6.253,0,5.805
        c0-0.994,0.315-1.816,0.945-2.467c0.63-0.651,1.459-0.978,2.488-0.978c2.016,0,3.22,1.047,3.611,3.14l3.611,16.512h0.095
        l5.028-16.041c0.42-1.302,0.945-2.229,1.575-2.782c0.63-0.553,1.424-0.83,2.383-0.83c0.952,0,1.729,0.275,2.331,0.824
        c0.602,0.55,1.113,1.479,1.533,2.787l5.039,16.042h0.084l3.611-16.513c0.399-2.094,1.603-3.14,3.611-3.14
        c1.043,0,1.877,0.326,2.504,0.978c0.626,0.65,0.939,1.473,0.939,2.467c0,0.763-0.231,1.939-0.693,3.527
        c-0.224,0.902-0.567,2.303-1.029,4.198c-0.462,1.897-1.158,4.749-2.089,8.557c-0.931,3.807-1.512,6.189-1.743,7.148
        c-0.378,1.666-0.955,2.801-1.732,3.4c-0.777,0.602-1.76,0.904-2.95,0.904c-2.464,0-4.112-1.266-4.945-3.791L19.735,15.65H19.64
        l-4.419,14.099c-0.448,1.273-1.064,2.225-1.848,2.85c-0.784,0.627-1.833,0.941-3.149,0.941c-1.134,0-2.094-0.277-2.882-0.83
        c-0.787-0.553-1.359-1.596-1.716-3.129c-0.679-2.891-1.384-5.822-2.115-8.797c-0.731-2.975-1.393-5.626-1.984-7.958
        C0.936,10.495,0.626,9.33,0.598,9.33h0.084V9.332z"/>
</g>

<g>
    <path fill="#FFFFFF" d="M0.682,9.332C0.654,9.192,0.533,8.682,0.32,7.8C0.107,6.918,0,6.253,0,5.805
        c0-0.994,0.315-1.816,0.945-2.467c0.63-0.651,1.459-0.978,2.488-0.978c2.016,0,3.22,1.047,3.611,3.14l3.611,16.512h0.095
        l5.028-16.041c0.42-1.302,0.945-2.229,1.575-2.782c0.63-0.553,1.424-0.83,2.383-0.83c0.952,0,1.729,0.275,2.331,0.824
        c0.602,0.55,1.113,1.479,1.533,2.787l5.039,16.042h0.084l3.611-16.513c0.399-2.094,1.603-3.14,3.611-3.14
        c1.043,0,1.877,0.326,2.504,0.978c0.626,0.65,0.939,1.473,0.939,2.467c0,0.763-0.231,1.939-0.693,3.527
        c-0.224,0.902-0.567,2.303-1.029,4.198c-0.462,1.897-1.158,4.749-2.089,8.557c-0.931,3.807-1.512,6.189-1.743,7.148
        c-0.378,1.666-0.955,2.801-1.732,3.4c-0.777,0.602-1.76,0.904-2.95,0.904c-2.464,0-4.112-1.266-4.945-3.791L19.735,15.65H19.64
        l-4.419,14.099c-0.448,1.273-1.064,2.225-1.848,2.85c-0.784,0.627-1.833,0.941-3.149,0.941c-1.134,0-2.094-0.277-2.882-0.83
        c-0.787-0.553-1.359-1.596-1.716-3.129c-0.679-2.891-1.384-5.822-2.115-8.797c-0.731-2.975-1.393-5.626-1.984-7.958
        C0.936,10.495,0.626,9.33,0.598,9.33h0.084V9.332z"/>
</g>
</svg>

after.svg

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 513 36"><defs><filter x="-30%" y="-30%" width="180%" height="180%"><feGaussianBlur in="SourceAlpha" stdDeviation=".25"/><feOffset dx="1" dy="1"/><feComponentTransfer><feFuncA type="linear" slope=".4"/></feComponentTransfer><feMerge><feMergeNode/><feMergeNode in="SourceGraphic"/></feMerge></filter></defs><path fill="#da107e" d="M.682 9.332c-.028-.14-.149-.65-.362-1.532s-.32-1.547-.32-1.995c0-.994.315-1.816.945-2.467.63-.651 1.459-.978 2.488-.978 2.016 0 3.22 1.047 3.611 3.14l3.611 16.512h.095l5.028-16.041c.42-1.302.945-2.229 1.575-2.782.63-.553 1.424-.83 2.383-.83.952 0 1.729.275 2.331.824.602.55 1.113 1.479 1.533 2.787l5.039 16.042h.084l3.611-16.513c.399-2.094 1.603-3.14 3.611-3.14 1.043 0 1.877.326 2.504.978.626.65.939 1.473.939 2.467 0 .763-.231 1.939-.693 3.527-.224.902-.567 2.303-1.029 4.198-.462 1.897-1.158 4.749-2.089 8.557-.931 3.807-1.512 6.189-1.743 7.148-.378 1.666-.955 2.801-1.732 3.4-.777.602-1.76.904-2.95.904-2.464 0-4.112-1.266-4.945-3.791l-4.472-14.097h-.095l-4.419 14.099c-.448 1.273-1.064 2.225-1.848 2.85-.784.627-1.833.941-3.149.941-1.134 0-2.094-.277-2.882-.83-.787-.553-1.359-1.596-1.716-3.129-.679-2.891-1.384-5.822-2.115-8.797-.731-2.975-1.393-5.626-1.984-7.958-.591-2.331-.901-3.496-.929-3.496h.084v.002z"/><path fill="#fff" d="M.682 9.332c-.028-.14-.149-.65-.362-1.532s-.32-1.547-.32-1.995c0-.994.315-1.816.945-2.467.63-.651 1.459-.978 2.488-.978 2.016 0 3.22 1.047 3.611 3.14l3.611 16.512h.095l5.028-16.041c.42-1.302.945-2.229 1.575-2.782.63-.553 1.424-.83 2.383-.83.952 0 1.729.275 2.331.824.602.55 1.113 1.479 1.533 2.787l5.039 16.042h.084l3.611-16.513c.399-2.094 1.603-3.14 3.611-3.14 1.043 0 1.877.326 2.504.978.626.65.939 1.473.939 2.467 0 .763-.231 1.939-.693 3.527-.224.902-.567 2.303-1.029 4.198-.462 1.897-1.158 4.749-2.089 8.557-.931 3.807-1.512 6.189-1.743 7.148-.378 1.666-.955 2.801-1.732 3.4-.777.602-1.76.904-2.95.904-2.464 0-4.112-1.266-4.945-3.791l-4.472-14.097h-.095l-4.419 14.099c-.448 1.273-1.064 2.225-1.848 2.85-.784.627-1.833.941-3.149.941-1.134 0-2.094-.277-2.882-.83-.787-.553-1.359-1.596-1.716-3.129-.679-2.891-1.384-5.822-2.115-8.797-.731-2.975-1.393-5.626-1.984-7.958-.591-2.331-.901-3.496-.929-3.496h.084v.002z"/></svg>