Don't rely on mtime to test changes

[ChrisDenton]

What does this PR try to resolve?

Fixes #13139 by making sure tests aren't relying on changing the mtime alone

How should we test and review this PR?

The pattern to watch out for is when a file is created with empty contents, e.g. .file("foo", ""), then later the same file updated with empty contents, e.g. .change_file("foo", ""). Tests should be making an actual change to the contents.

[rustbot]

r? @weihanglo

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[weihanglo]

Seems unrelated, but I wonder what it is 🤔

---- features::no_feature_doesnt_build stdout ----
running `D:\a\cargo\cargo\target\debug\cargo.exe build`
running `D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\foo.exe`
running `D:\a\cargo\cargo\target\debug\cargo.exe build --features bar -v`
thread 'features::no_feature_doesnt_build' panicked at tests\testsuite\features.rs:525:10:

test failed running `D:\a\cargo\cargo\target\debug\cargo.exe build --features bar -v`
error: process exited with code 101 (expected 0)
--- stdout

--- stderr
   Compiling bar v0.0.1 (D:\a\cargo\cargo\target\tmp\cit\t1334\foo\bar)
     Running `rustc --crate-name bar bar\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 -C metadata=66d2c9045771087b -C extra-filename=-66d2c9045771087b --out-dir D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps -L dependency=D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps`
   Compiling foo v0.0.1 (D:\a\cargo\cargo\target\tmp\cit\t1334\foo)
     Running `rustc --crate-name foo src\main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 --cfg "feature=\"bar\"" -C metadata=7fe94a9cbff53163 -C extra-filename=-7fe94a9cbff53163 --out-dir D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps -L dependency=D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps --extern bar=D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps\libbar-66d2c9045771087b.rlib`
error: couldn't create a temp dir: Access is denied. (os error 5) at path "C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\rustcXRSPPA"

error: could not compile `foo` (bin "foo") due to 1 previous error

Caused by:
  process didn't exit successfully: `rustc --crate-name foo src\main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 --cfg "feature=\"bar\"" -C metadata=7fe94a9cbff53163 -C extra-filename=-7fe94a9cbff53163 --out-dir D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps -L dependency=D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps --extern bar=D:\a\cargo\cargo\target\tmp\cit\t1334\foo\target\debug\deps\libbar-66d2c9045771087b.rlib` (exit code: 1)

[ChrisDenton]

That seems weird but yeah, I'm not seeing how it could be related to this PR unless tests are tripping over each other (which they shouldn't be, obv). But I'm also not seeing it affecting other PRs. Maybe spurious?

An access denied error can occur for a few different reasons, including permissions errors or if the directory exists and a delete is pending. But I'm not sure any apply to a temp dir.

[weihanglo]

@bors r+

[bors]

📌 Commit 4ef503f has been approved by weihanglo

It is now in the queue for this repository.

[bors]

⌛ Testing commit 4ef503f with merge 047dc18...

[bors]

☀️ Test successful - checks-actions
Approved by: weihanglo
Pushing 047dc18 to master...