Template Part: 403 request error occurs in edit mode

[t-hamano]

Description

When I open any template part in the site editor, a 403 error is recorded in the browser console:

{
    "code": "rest_cannot_read",
    "message": "Sorry, you are not allowed to view autosaves of this post.",
    "data": {
        "status": 403
    }
}

After investigating the problem, it appears that this issue occurred in #61273.

For example, if I temporarily comment out the Header component as shown below, the console error will disappear:

diff --git a/packages/editor/src/components/editor-interface/index.js b/packages/editor/src/components/editor-interface/index.js
index 6f6ffbec7b..c43dbe6383 100644
--- a/packages/editor/src/components/editor-interface/index.js
+++ b/packages/editor/src/components/editor-interface/index.js
@@ -112,19 +112,19 @@ export default function EditorInterface( {
                                ...interfaceLabels,
                                secondarySidebar: secondarySidebarLabel,
                        } }
-                       header={
-                               ! isPreviewMode && (
-                                       <Header
-                                               forceIsDirty={ forceIsDirty }
-                                               setEntitiesSavedStatesCallback={
-                                                       setEntitiesSavedStatesCallback
-                                               }
-                                               customSaveButton={ customSaveButton }
-                                               forceDisableBlockTools={ forceDisableBlockTools }
-                                               title={ title }
-                                       />
-                               )
-                       }
+                       // header={
+                       //      ! isPreviewMode && (
+                       //              <Header
+                       //                      forceIsDirty={ forceIsDirty }
+                       //                      setEntitiesSavedStatesCallback={
+                       //                              setEntitiesSavedStatesCallback
+                       //                      }
+                       //                      customSaveButton={ customSaveButton }
+                       //                      forceDisableBlockTools={ forceDisableBlockTools }
+                       //                      title={ title }
+                       //              />
+                       //      )
+                       // }
                        editorNotices={ <EditorNotices /> }
                        secondarySidebar={
                                ! isPreviewMode &&

It is likely that some request in the Header component is causing this error. I'm investigating the cause.

Step-by-step reproduction instructions

• Open any template part in the site editor.
• Check the browser console.

Screenshots, screen recording, code snippet

Environment info

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[Mamaduka]

The error is a known issue and needs to be fixed in the core. See: WordPress/wordpress-develop#7272.

However, not sure why the code change from your example affects the behavior.

Also related: #64733.

[im3dabasia]

Thank you @t-hamano for raising the issue.

I can confirm that a 403 error is recorded in the browser console.

[t-hamano]

@Mamaduka Thanks for letting me know!

From what I've researched, it seems like this error is happening with this request:

gutenberg/packages/editor/src/components/post-preview-button/index.js

Line 136 in 7b6e775

previewLink: editor.getEditedPostPreviewLink(),

I'm thinking that it might be a good idea to check isViewable beforehand as a condition for rendering the PostPreviewButton itself. If viewable is false, there's no need to get the preview link in the first place.

[t-hamano]

I'm thinking that it might be a good idea to check isViewable beforehand as a condition for rendering the PostPreviewButton itself. If viewable is false, there's no need to get the preview link in the first place.

I'm starting to wonder if this approach is ideal.

Sure, it solves the problem with the PostPreviewButton component, but it doesn't solve the problem with the endpoint itself.

Maybe it's better to close this issue and move forward with WordPress/wordpress-develop#7272?

[Mamaduka]

@t-hamano, yes, the core PR will resolve the root cause of the issue. However, this is also an opportunity for minor performance improvements for this component.

Here's my alternative PR #68678.

cc @dhananjaykuber.