teach add_submodule_odb() to look for alternates

Since we allow to link other object databases when loading a submodules
database we should also load possible alternates.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index 3a8e125..3a28cb1 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -960,6 +960,7 @@ extern struct alternate_object_database {
        char base[FLEX_ARRAY]; /* more */
 } *alt_odb_list;
 extern void prepare_alt_odb(void);
+extern void read_info_alternates(const char * relative_base, int depth);
 extern void add_to_alternates_file(const char *reference);
 typedef int alt_odb_fn(struct alternate_object_database *, void *);
 extern void foreach_alt_odb(alt_odb_fn, void*);

diff --git a/sha1_file.c b/sha1_file.c
index 4f06a0e..f615fc7 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -228,7 +228,6 @@ char *sha1_pack_index_name(const unsigned char *sha1)
 struct alternate_object_database *alt_odb_list;
 static struct alternate_object_database **alt_odb_tail;
 
-static void read_info_alternates(const char * alternates, int depth);
 static int git_open_noatime(const char *name);
 
 /*
@@ -353,7 +352,7 @@ static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
        }
 }
 
-static void read_info_alternates(const char * relative_base, int depth)
+void read_info_alternates(const char * relative_base, int depth)
 {
        char *map;
        size_t mapsz;

diff --git a/submodule.c b/submodule.c
index 9a28060..b63978a 100644 (file)
--- a/submodule.c
+++ b/submodule.c
@@ -63,6 +63,9 @@ static int add_submodule_odb(const char *path)
        alt_odb->name[40] = '\0';
        alt_odb->name[41] = '\0';
        alt_odb_list = alt_odb;
+
+       /* add possible alternates from the submodule */
+       read_info_alternates(objects_directory.buf, 0);
        prepare_alt_odb();
 done:
        strbuf_release(&objects_directory);

diff --git a/t/t4041-diff-submodule-option.sh b/t/t4041-diff-submodule-option.sh
index bf9a752..6c01d0c 100755 (executable)
--- a/t/t4041-diff-submodule-option.sh
+++ b/t/t4041-diff-submodule-option.sh
@@ -458,4 +458,38 @@ EOF
        test_cmp expected actual
 '
 
+test_expect_success 'diff --submodule with objects referenced by alternates' '
+       mkdir sub_alt &&
+       (cd sub_alt &&
+               git init &&
+               echo a >a &&
+               git add a &&
+               git commit -m a
+       ) &&
+       mkdir super &&
+       (cd super &&
+               git clone -s ../sub_alt sub &&
+               git init &&
+               git add sub &&
+               git commit -m "sub a"
+       ) &&
+       (cd sub_alt &&
+               sha1_before=$(git rev-parse --short HEAD)
+               echo b >b &&
+               git add b &&
+               git commit -m b
+               sha1_after=$(git rev-parse --short HEAD)
+               echo "Submodule sub $sha1_before..$sha1_after:
+  > b" >../expected
+       ) &&
+       (cd super &&
+               (cd sub &&
+                       git fetch &&
+                       git checkout origin/master
+               ) &&
+               git diff --submodule > ../actual
+       )
+       test_cmp expected actual
+'
+
 test_done