fix: do not display code intelligence hovers on Sourcegraph Extension…

…line decorations

Prior to this change, hovering over text/links provided by a Sourcegraph Extension would trigger the display of the hover 'loading' indicator. On most files, it goes away quickly (just a flicker), but on some it displays an error:

![image](https://user-images.githubusercontent.com/3173176/45585161-caaff580-b894-11e8-8b3f-10347f2aa438.png)

After this change, we no longer attempt to display hovers etc. on the DOM elements which Sourcegraph Extensions provide.

Fixes sourcegraph/sourcegraph-extension-api#67

Author: Stephen Gutekanst

src/libs/code_intelligence/code_intelligence.tsx

@@ -365,6 +365,19 @@ function handleCodeHost(codeHost: CodeHost): Subscription {
                     const toURIWithPath = (ctx: AbsoluteRepoFile) =>
                         `git://${ctx.repoPath}?${ctx.commitID}#${ctx.filePath}`
 
+                    const originalDOM = dom
+                    dom = {
+                        ...dom,
+                        // If any parent element has the sourcegraph-extension-element
+                        // class then that element does not have any code. We
+                        // must check for "any parent element" because extensions
+                        // create their DOM changes before the blob is tokenized
+                        // into multiple elements.
+                        getCodeElementFromTarget: (target: HTMLElement): HTMLElement | null =>
+                            target.closest('.sourcegraph-extension-element') !== null
+                                ? null
+                                : originalDOM.getCodeElementFromTarget(target),
+                    }
                     if (extensionsController) {
                         const { content, baseContent } = getContentOfCodeView(codeView, { isDiff, getLineRanges, dom })
 

src/libs/code_intelligence/extensions.tsx

@@ -174,13 +174,15 @@ export const applyDecoration = (
     if (decoration.after) {
         const linkTo = (url: string) => (e: HTMLElement): HTMLElement => {
             const link = document.createElement('a')
+            link.className = 'sourcegraph-extension-element'
             link.setAttribute('href', url)
             link.style.color = decoration.after!.color || null
             link.appendChild(e)
             return link
         }
 
         const after = document.createElement('span')
+        after.className = 'sourcegraph-extension-element'
         after.style.backgroundColor = decoration.after.backgroundColor || null
         after.textContent = decoration.after.contentText || null