From: Stefan Sperling <stsp@stsp.name>
Subject: allow changing default hash algorithm in gotsys.conf
To: gameoftrees@openbsd.org
Date: Fri, 23 Oct 2026 15:00:00 +0200

Makes life a bit simpler for people who really don't want to jump
onto the Git SHA256 train just yet.

ok?
 
M  gotsys/gotsys.conf.5  |  18+  1-
M  gotsys/gotsys.h       |   1+  0-
M  gotsys/parse.y        |  28+  0-
M  lib/gotsys_conf.c     |   3+  1-

4 files changed, 50 insertions(+), 2 deletions(-)

commit - fc83c481c4940f4ac250a21c4dac396a9f60bb78
commit + c99905d093df810ae083b6382b24bf1be150c9ba
blob - 334eba2c3537abef7debd35788f38e98533a240d
blob + b19d6037dc09a70f981cebbf89b8a9e3281224d1
--- gotsys/gotsys.conf.5
+++ gotsys/gotsys.conf.5
@@ -43,6 +43,21 @@ are treated as comments and ignored.
 .Sh GLOBAL CONFIGURATION
  The available global configuration directives are as follows:
 .Bl -tag -width Ds
+.It Ic hash algorithm Ar hashing-algorithm
+Configure the default
+.Ar hashing-algorithm
+used for the computation of Git object IDs.
+Possible values are
+.Dq sha256
+.Pq the default
+or
+.Dq sha1 .
+.Pp
+This configuration directive only affects newly created repositories.
+The hashing algorithm of existing repositories cannot be changed.
+.Pp
+The default hash algorithm can be overridden with per-repository
+configuration directives described below.
 .It Ic group Ar name
 Declare a group with the given
 .Ar name .
@@ -296,9 +311,11 @@ Configure the repository's
 used for the computation of Git object IDs.
 Possible values are
 .Dq sha256
-.Pq the default
 or
 .Dq sha1 .
+If not set, the value set in the global configuration context will be used,
+which defaults to
+.Dq sha256 .
 .Pp
 This configuration directive only affects newly created repositories.
 The hashing algorithm of existing repositories cannot be changed.
blob - c2049433c8393df1affc57a5d92371e126268a7d
blob + ce6c5d7b0d41bd2c926d1d2ccee55ebd84003dc3
--- gotsys/gotsys.h
+++ gotsys/gotsys.h
@@ -172,6 +172,7 @@ struct gotsys_conf {
 	int nrepos;
 	struct gotsys_webserverlist webservers;
 	struct mediatypes mediatypes;
+	enum got_hash_algorithm default_algo;
 };
 
 void gotsys_conf_init(struct gotsys_conf *);
blob - 06a5f4c11720b289740d52fe2c60a9cc64c63cf4
blob + 507cefc9d463914e9cccf75897586e9e1b8f297e
--- gotsys/parse.y
+++ gotsys/parse.y
@@ -238,6 +238,27 @@ main		: USER STRING {
 		| MEDIA TYPES '{' optnl mediaopts_l '}' {
 			new_mediatypes = &gotsysconf->mediatypes;
 		}
+		| HASH ALGORITHM STRING {
+			const struct got_error *err;
+			enum got_hash_algorithm algo;
+
+			err = gotsys_conf_validate_hash_algo(&algo, $3);
+			if (err) {
+				yyerror("%s", err->msg);
+				free($3);
+				YYERROR;
+			}
+
+			if (gotsysconf->default_algo != GOT_NUM_HASH_ALGOS) {
+				yyerror("the default hash algorithm can only "
+				    "be specified once");
+				free($3);
+				YYERROR;
+			}
+
+			gotsysconf->default_algo = algo;
+			free($3);
+		}
 		;
 
 useropts1	: GROUP STRING {
@@ -1659,6 +1680,13 @@ gotsys_conf_parse(const char *filename, struct gotsys_
 		    "repository %s.git", GOTSYS_SYSTEM_REPOSITORY_NAME);
 	}
 
+	if (gotsysconf->default_algo == GOT_NUM_HASH_ALGOS)
+		gotsysconf->default_algo = GOT_HASH_SHA256;
+	TAILQ_FOREACH(repo, &gotsysconf->repos, entry) {
+		if (repo->algo == GOT_NUM_HASH_ALGOS)
+			repo->algo = gotsysconf->default_algo;
+	}
+
 	STAILQ_FOREACH(srv, &gotsysconf->webservers, entry) {
 		struct gotsys_webrepo *webrepo;
 		struct gotsys_repo *repo;
blob - dbea080c327ee70d65515a0206d9eff88e8953ef
blob + 202f7991dd065f22b089bc94abec09f9aa73caed
--- lib/gotsys_conf.c
+++ lib/gotsys_conf.c
@@ -59,6 +59,8 @@ gotsys_conf_init(struct gotsys_conf *gotsysconf)
 	TAILQ_INIT(&gotsysconf->repos);
 	STAILQ_INIT(&gotsysconf->webservers);
 	RB_INIT(&gotsysconf->mediatypes);
+
+	gotsysconf->default_algo = GOT_NUM_HASH_ALGOS; /* unset */
 }
 
 const struct got_error *
@@ -908,7 +910,7 @@ gotsys_conf_new_repo(struct gotsys_repo **new_repo, co
 		    "repository name too long: %s", name);
 	}
 
-	repo->algo = GOT_HASH_SHA256;
+	repo->algo = GOT_NUM_HASH_ALGOS; /* unset */
 
 	*new_repo = repo;
 	return NULL;