Incremental Static Regeneration replaces `.amp` with `?amp=1`

[wawoon]

Bug report

Describe the bug

• When the page is built with Amp and SSG config, the output url of amp page becomes /foo.amp (routing is pages/[slug])
• In the build phase, the non-amp page /foo refers to /foo.amp in <link rel="amphtml"> correctly.
• However when Incremental Static Regeneration is turned on, the /foo.amp is replaced with /foo?amp=1

To Reproduce

set

• amp: "hybrid"
• add unstable_revalidate: 30 to getStaticProps return value.

reproduce:
https://github.com/wawoon/next-amp-ssg-reproduce

yarn build
yarn start
go to http://localhost:3000/foo

Expected behavior

The non amp page should always refer to/foo.amp in <link rel="amphtml"> tag even if Incremental Static Regeneration is turned on.

Screenshots

initial access:

after 30sec

System information

• macOS
• Chrome
• Next: 9.4.5-canary.12
• Node: v12.14.1

Additional context

#13038
#13046

[mohamedsgap]

@Timer can i take this one ?

[Timer]

Sure!

[ngocnv-0940]

Any update?