1649704 - Improve consistency of Span's span_iterator comparison

Status: RESOLVED FIXED

(Core :: MFBT, task)

Description

[Simon Giesecke [:sg] [he/him]]

Currently, comparing span_iterator instances from different span instances will

• will report them as unequal when compared via == or !=
• will trigger a release-mode assertion failure when compared via <, <=, > or >=
  which seems inconsistent.

The second behaviour seems more sound. However, a MOZ_DIAGNOSTIC_ASSERT should be enough here since this doesn't affect the validity of iterator accesses.

Apart from that, it might be surprising that iterators derived from different spans are not comparable even if they were derived from the same base span using Subspan or similar methods. However, possibly changing this is a different issue. In the context of this bug, I will just add a comment to make that clearer.

Comment 1

[Simon Giesecke [:sg] [he/him]]

Attachment: Bug 1649704 - Improve consistency of Span's span_iterator comparison. r=froydnj

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a22dfb5eb460
Improve consistency of Span's span_iterator comparison. r=froydnj

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/a22dfb5eb460