Bug 94704 – REGRESSION(r126189): Reftest mismatches are (again) run through ImageDiff with 0.1 tolerance

• Component: New Bugs
• Status: RESOLVED FIXED

[Zan Dobersek]

REGRESSION(r126189): Reftest mismatches are (again) run through ImageDiff with 0.1 tolerance

[Zan Dobersek]

Created attachment 159923 [details]
Patch

[Zan Dobersek]

Perhaps a reincarnation of bug #92847, this caused some tests to pop up as passing. Too bad.

[Dirk Pranke]

Oh, that's my fault. Will look into it in a bit ...

[Eric Seidel (no email)]

How do we test this so it doesn't happen again?

[Dirk Pranke]

Actually, to clarify ... this is not a regression of bug #92847. This was caused by the fix I landed for bug 94540 (r126189). At some point, we stopped calling diff_image() for reftests and were just comparing checksums. This seemed to be bad (at least for the Apple Mac port) and so I added the diff_image as a sanity check.

It wasn't clear to me at the time (and still isn't) whether we should use the default tolerance for the port, or use 0 (and thus ref tests and pixel tests would potentially be compared with different tolerances). I can see arguments for either way, and perhaps this should be a separate default setting.

In the absence of agreeing over what we want to do here, it's not obvious what the test should be testing ;).

That said, I'll R+ this as I *think* the Apple Mac port doesn't actually need fuzzy diffs and so this shouldn't break things. I guess we can find out.

[Dirk Pranke]

Comment on attachment 159923 [details]
Patch

Also, we should add some sort of a test for this (per eric's comment), but I don't want to hold up this fix for that. I'll file a separate bug.

[WebKit Review Bot]

Comment on attachment 159923 [details]
Patch

Clearing flags on attachment: 159923

Committed r126353: <http://trac.webkit.org/changeset/126353>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.