Chrome slow to upload in topic with many images

sam · September 12, 2024, 5:36am

Looking at the backtrace it looks like a bug here:

discourse/discourse/blob/7ced4fccc7d5bb41f60e7c51be55bb03de215634/app/assets/javascripts/discourse/app/mixins/textarea-text-manipulation.js#L132-L174


      
          replaceText(oldVal, newVal, opts = {}) {
            const val = this.value;
            const needleStart = val.indexOf(oldVal);
          
            if (needleStart === -1) {
              // Nothing to replace.
              return;
            }
          
            // Determine post-replace selection.
            const newSelection = determinePostReplaceSelection({
              selection: {
                start: this._textarea.selectionStart,
                end: this._textarea.selectionEnd,
              },
              needle: { start: needleStart, end: needleStart + oldVal.length },
              replacement: { start: needleStart, end: needleStart + newVal.length },
            });
          
            if (opts.index && opts.regex) {

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But all the time is being spent here:

github.com

discourse/discourse/blob/7ced4fccc7d5bb41f60e7c51be55bb03de215634/app/assets/javascripts/discourse/app/mixins/textarea-text-manipulation.js#L332-L336


      
          _insertAt(start, end, text) {
            this._textarea.setSelectionRange(start, end);
            this._textarea.focus();
            document.execCommand("insertText", false, text);
          },

This is super confusing though, why would insertText suddenly get so slow, this certainly feels like a chrome bug.

Will ping a few team members in case they have ideas.

Could this be a chrome extension, if you run chrome in safe mode does the issue persist?