doc hash-function-transition: clarify how older gits die on NewHash

avar · gitster · commit 45fa195ff0b7 · 2018-03-27T19:07:51.000-07:00
Change the "Repository format extension" to accurately describe what happens with different versions of Git when they encounter NewHash repositories, instead of only saying what happens with versions v2.7.0 and later. See ab9cb76 ("Repository format version check.", 2005-11-25) and 00a09d5 ("introduce "extensions" form of core.repositoryformatversion", 2015-06-23) for the relevant changes to the setup code where these variables are checked. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt
@@ -116,10 +116,15 @@ Documentation/technical/repository-version.txt) with extensions
 		objectFormat = newhash
 		compatObjectFormat = sha1
 
-Specifying a repository format extension ensures that versions of Git
-not aware of NewHash do not try to operate on these repositories,
-instead producing an error message:
+The combination of setting `core.repositoryFormatVersion=1` and
+populating `extensions.*` ensures that all versions of Git later than
+`v0.99.9l` will die instead of trying to operate on the NewHash
+repository, instead producing an error message.
 
+	# Between v0.99.9l and v2.7.0
+	$ git status
+	fatal: Expected git repo version <= 0, found 1
+	# After v2.7.0
 	$ git status
 	fatal: unknown repository extensions found:
 		objectformat
