scrape-examples does not fingerprint correctly

[ehuss]

Problem

Running cargo doc twice with -Zrustdoc-scrape-examples, the second run should not do anything. However, it is running rustdoc again to scrape the examples.

Steps

Changing the scrape_examples_basic test to run cargo doc one more time should not execute anything. However, it is redoing the scrape.

diff --git a/tests/testsuite/doc.rs b/tests/testsuite/doc.rs
index 00971c2cd..760cb47ce 100644
--- a/tests/testsuite/doc.rs
+++ b/tests/testsuite/doc.rs
@@ -2395,6 +2395,11 @@ fn scrape_examples_basic() {

     // Ensure that the reverse-dependency has its sources generated
     assert!(p.build_dir().join("doc/src/ex/ex.rs.html").exists());
+
+    p.cargo("doc -Zunstable-options -Z rustdoc-scrape-examples=all")
+        .masquerade_as_nightly_cargo(&["rustdoc-scrape-examples"])
+        .with_stderr("[FINISHED] ..")
+        .run();
 }

 #[cargo_test]

Possible Solution(s)

I have not looked, but I suspect the fingerprinting of Docscrape units isn't working.

Notes

No response

Version

cargo 1.64.0-nightly (8827baaa7 2022-07-14)
release: 1.64.0-nightly
commit-hash: 8827baaa781b37872134c1ba692a6f0aeb37890e
commit-date: 2022-07-14
host: x86_64-apple-darwin
libgit2: 1.4.2 (sys:0.14.2 vendored)
libcurl: 7.79.1 (sys:0.4.55+curl-7.83.1 system ssl:(SecureTransport) LibreSSL/3.3.6)
os: Mac OS 12.4.0 [64-bit]

[weihanglo]

fixed by #10343