tests: use grep -E instead of obsolescent egrep Testing on Fedora 38 failed with: egrep: warning: egrep is obsolescent; using grep -E The warning comes from https://git.savannah.gnu.org/cgit/grep.git/commit/?id=a9515624709865d480e3142fd959bccd1c9372d1 . For further anecdotal evidence of the change, see https://www.phoronix.com/news/GNU-Grep-3.8-Stop-egrep-fgrep . This reverses the code check that goes back to e7d3b509af8b. grep -E is POSIX, but there is a risk that it doesn't work the same on all platforms - especially older Unix versions. It should however always be possible to put a GNU grep in $PATH before running the tests.

--- a/tests/test-context-metadata.t	Mon Jun 26 11:15:30 2023 +0100
+++ b/tests/test-context-metadata.t	Mon Jun 26 14:34:58 2023 +0200
@@ -36,7 +36,7 @@
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     Changed
   
-  $ hg --config extensions.metaedit=$TESTTMP/metaedit.py metaedit 'parents=0' 2>&1 | egrep '^RuntimeError'
+  $ hg --config extensions.metaedit=$TESTTMP/metaedit.py metaedit 'parents=0' 2>&1 | grep -E '^RuntimeError'
   RuntimeError: can't reuse the manifest: its p1 doesn't match the new ctx p1
 
   $ hg --config extensions.metaedit=$TESTTMP/metaedit.py metaedit 'user=foo <foo@example.com>'