[FIX] web_editor: make image options start more robust

This commit makes the image options initialization more robust, by

- checking at the beginning if the specified `src` and `data-original-
src` attributes match with existing files.
- checking if there is a `data-original-src` attribute before applying
the ImageTools options (shape, filter,...).

This is needed because in the case of wrongly hardcoded templates (e.g.
in customizations), it is sometimes not possible to drop any snippet
after dropping an incorrect one. This happens because the image
`SnippetEditor` is not correctly created. Indeed, the start of the image
options is never completed because the promise rejections when a file
does not exist are not properly caught, interrupting the initialization.
Therefore, ensuring that the files exist beforehand prevents these
issues from happening.

opw-3137732

closes odoo/odoo#118546

X-original-commit: 93ddaac87a76d6d1775e0b3e30bb66ca85147503
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/web_editor/static/src/js/editor/snippets.options.js

@@ -5797,6 +5797,12 @@ const ImageHandlerOption = SnippetOptionWidget.extend({
             this._filesize = undefined;
             return;
         }
+        // Do not apply modifications if there is no original src, since it is
+        // needed for it.
+        if (!img.dataset.originalSrc) {
+            delete img.dataset.mimetype;
+            return;
+        }
         const dataURL = await applyModifications(img, {mimetype: this._getImageMimetype(img)});
         this._filesize = dataURL.split(',')[1].length / 4 * 3 / 1024;
 
@@ -6364,7 +6370,37 @@ registry.ImageTools = ImageHandlerOption.extend({
      * @private
      */
     async _initializeImage() {
-        const img = this._getImg();
+        const _super = this._super.bind(this);
+        let img = this._getImg();
+
+        // Check first if the `src` and eventual `data-original-src` attributes
+        // are correct (i.e. the await are not rejected), as they may have been
+        // wrongly hardcoded in some templates.
+        let checkedAttribute = 'src';
+        try {
+            await loadImage(img.src);
+            if (img.dataset.originalSrc) {
+                checkedAttribute = 'originalSrc';
+                await loadImage(img.dataset.originalSrc);
+            }
+        } catch {
+            if (checkedAttribute === 'src') {
+                // If `src` does not exist, replace the image by a placeholder.
+                Object.keys(img.dataset).forEach(key => delete img.dataset[key]);
+                img.dataset.mimetype = 'image/png';
+                const newSrc = '/web/image/web.image_placeholder';
+                img = await loadImage(newSrc, img);
+                return this._loadImageInfo(newSrc);
+            } else {
+                // If `data-original-src` does not exist, remove the `data-
+                // original-*` attributes (they will be set correctly afterwards
+                // in `_loadImageInfo`).
+                delete img.dataset.originalId;
+                delete img.dataset.originalSrc;
+                delete img.dataset.originalMimetype;
+            }
+        }
+
         let match = img.src.match(/\/web_editor\/image_shape\/(\w+\.\w+)/);
         if (img.dataset.shape && match) {
             match = match[1];
@@ -6377,7 +6413,7 @@ registry.ImageTools = ImageHandlerOption.extend({
             }
             return this._loadImageInfo(`/web/image/${match}`);
         }
-        return this._super(...arguments);
+        return _super(...arguments);
     },
     /**
      * @override