Bug 1483498 [wpt PR 12493] - Document rough consensus on reverting ch…

…anges, a=testonly

Automatic update from web-platform-testsDocument rough consensus on reverting changes (#12493)

Fixes web-platform-tests/wpt#9953.
--

wpt-commits: 7abda4e7227b65fba2452980d106ed5f11d51b2b
wpt-pr: 12493

UltraBlame original commit: 4b4863b6778762764d7d8f9b4cb37f946019d800

testing/web-platform/meta/MANIFEST.json

@@ -1675917,6 +1675917,22 @@ docs
 /
 _appendix
 /
+reverting
+.
+md
+"
+:
+[
+[
+{
+}
+]
+]
+"
+docs
+/
+_appendix
+/
 test
 -
 templates
@@ -3836781,6 +3836797,24 @@ docs
 /
 _appendix
 /
+reverting
+.
+md
+"
+:
+[
+"
+1f549b3a341f2a78a16be835ae43e2d8da5b7137
+"
+"
+support
+"
+]
+"
+docs
+/
+_appendix
+/
 test
 -
 templates

testing/web-platform/tests/docs/_appendix/reverting.md

@@ -0,0 +1,274 @@
+-
+-
+-
+layout
+:
+page
+title
+:
+Reverting
+Changes
+order
+:
+3
+-
+-
+-
+Testing
+is
+imperfect
+and
+from
+time
+to
+time
+changes
+are
+merged
+into
+master
+which
+break
+things
+for
+users
+of
+web
+-
+platform
+-
+tests
+.
+Such
+breakage
+can
+include
+:
+*
+Failures
+in
+Travis
+or
+Taskcluster
+runs
+for
+this
+repository
+either
+on
+the
+master
+branch
+or
+on
+pull
+requests
+following
+the
+breaking
+change
+.
+*
+Breakage
+in
+browser
+engine
+repositories
+which
+import
+and
+run
+web
+-
+platform
+-
+tests
+such
+as
+Chromium
+Edge
+Gecko
+Servo
+and
+WebKit
+.
+*
+Breakage
+in
+results
+collections
+systems
+for
+results
+dashboards
+such
+as
+[
+wpt
+.
+fyi
+]
+(
+https
+:
+/
+/
+wpt
+.
+fyi
+)
+.
+*
+Breakage
+in
+supplemental
+tooling
+used
+by
+working
+groups
+such
+as
+the
+[
+CSS
+build
+system
+]
+[
+]
+.
+When
+such
+breakage
+happens
+if
+the
+maintainers
+of
+the
+affected
+systems
+request
+it
+pull
+requests
+to
+revert
+the
+original
+change
+should
+normally
+be
+approved
+and
+merged
+as
+soon
+as
+possible
+.
+(
+When
+the
+original
+change
+itself
+was
+fixing
+a
+serious
+problem
+it
+'
+s
+a
+judgement
+call
+but
+prefer
+the
+fastest
+path
+to
+a
+stable
+state
+acceptable
+to
+everyone
+.
+)
+Once
+a
+revert
+has
+happened
+the
+maintainers
+of
+the
+affected
+systems
+are
+expected
+to
+work
+with
+the
+original
+patch
+author
+to
+resolve
+the
+problem
+so
+that
+the
+change
+can
+be
+relanded
+.
+A
+reasonable
+timeframe
+to
+do
+so
+is
+within
+one
+week
+.
+[
+CSS
+build
+system
+]
+:
+https
+:
+/
+/
+github
+.
+com
+/
+web
+-
+platform
+-
+tests
+/
+wpt
+/
+tree
+/
+master
+/
+css
+/
+tools