commit-graph.h: replace 'commit_hex' with 'commits'

The 'write_commit_graph()' function takes in either a string list of
pack indices, or a string list of hexadecimal commit OIDs. These
correspond to the '--stdin-packs' and '--stdin-commits' mode(s) from
'git commit-graph write'.

Using a string_list of hexadecimal commit IDs is not the most efficient
use of memory, since we can instead use the 'struct oidset', which is
more well-suited for this case.

This has another benefit which will become apparent in the following
commit. This is that we are about to disambiguate the kinds of errors we
produce with '--stdin-commits' into "non-hex input" and "hex-input, but
referring to a non-commit object". By having 'write_commit_graph' take
in a 'struct oidset *' of commits, we place the burden on the caller (in
this case, the builtin) to handle the first case, and the commit-graph
machinery can handle the second case.

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 0bf98b56ec..69599cea7f 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -43,7 +43,7 @@ test_expect_success 'create commits and repack' '
 test_expect_success 'exit with correct error on bad input to --stdin-commits' '
 	cd "$TRASH_DIRECTORY/full" &&
 	echo HEAD | test_expect_code 1 git commit-graph write --stdin-commits 2>stderr &&
-	test_i18ngrep "invalid commit object id" stderr &&
+	test_i18ngrep "unexpected non-hex object ID: HEAD" stderr &&
 	# valid tree OID, but not a commit OID
 	git rev-parse HEAD^{tree} | test_expect_code 1 git commit-graph write --stdin-commits 2>stderr &&
 	test_i18ngrep "invalid commit object id" stderr