There is currently an odd behaviour when locally cloning a repository
with symlinks at .git/objects: using --no-hardlinks all symlinks are
dereferenced but without it, Git will try to hardlink the files with the
link() function, which has an OS-specific behaviour on symlinks. On OSX
and NetBSD, it creates a hardlink to the file pointed by the symlink
whilst on GNU/Linux, it creates a hardlink to the symlink itself.

On Manjaro GNU/Linux:
    $ touch a
    $ ln -s a b
    $ link b c
    $ ls -li a b c
    155 [...] a
    156 [...] b -> a
    156 [...] c -> a

But on NetBSD:
    $ ls -li a b c
    2609160 [...] a
    2609164 [...] b -> a
    2609160 [...] c

It's not good to have the result of a local clone to be OS-dependent and
besides that, the current behaviour on GNU/Linux may result in broken
symlinks. So let's standardize this by making the hardlinks always point
to dereferenced paths, instead of the symlinks themselves. Also, add
tests for symlinked files at .git/objects/.

Note: Git won't create symlinks at .git/objects itself, but it's better
to handle this case and be friendly with users who manually create them.

Signed-off-by: Matheus Tavares <matheus.bernard...@usp.br>
Signed-off-by: Ævar Arnfjörð Bjarmason <ava...@gmail.com>
Co-authored-by: Ævar Arnfjörð Bjarmason <ava...@gmail.com>
---
 builtin/clone.c            |  2 +-
 t/t5604-clone-reference.sh | 27 ++++++++++++++++++++-------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/builtin/clone.c b/builtin/clone.c
index 5b9ebe9947..4a0a2455a7 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -445,7 +445,7 @@ static void copy_or_link_directory(struct strbuf *src, 
struct strbuf *dest,
                if (unlink(dest->buf) && errno != ENOENT)
                        die_errno(_("failed to unlink '%s'"), dest->buf);
                if (!option_no_hardlinks) {
-                       if (!link(src->buf, dest->buf))
+                       if (!link(real_path(src->buf), dest->buf))
                                continue;
                        if (option_local > 0)
                                die_errno(_("failed to create link '%s'"), 
dest->buf);
diff --git a/t/t5604-clone-reference.sh b/t/t5604-clone-reference.sh
index 207650cb95..0800c3853f 100755
--- a/t/t5604-clone-reference.sh
+++ b/t/t5604-clone-reference.sh
@@ -266,7 +266,7 @@ test_expect_success 'clone a repo with garbage in 
objects/*' '
        test_cmp expected actual
 '
 
-test_expect_success SYMLINKS 'setup repo with manually symlinked dirs and 
unknown files at objects/' '
+test_expect_success SYMLINKS 'setup repo with manually symlinked or unknown 
files at objects/' '
        git init T &&
        (
                cd T &&
@@ -280,10 +280,19 @@ test_expect_success SYMLINKS 'setup repo with manually 
symlinked dirs and unknow
                ln -s packs pack &&
                find ?? -type d >loose-dirs &&
                last_loose=$(tail -n 1 loose-dirs) &&
-               rm -f loose-dirs &&
                mv $last_loose a-loose-dir &&
                ln -s a-loose-dir $last_loose &&
+               first_loose=$(head -n 1 loose-dirs) &&
+               rm -f loose-dirs &&
+
+               cd $first_loose &&
+               obj=$(ls *) &&
+               mv $obj ../an-object &&
+               ln -s ../an-object $obj &&
+
+               cd ../ &&
                find . -type f | sort >../../../T.objects-files.raw &&
+               find . -type l | sort >../../../T.objects-symlinks.raw &&
                echo unknown_content> unknown_file
        ) &&
        git -C T fsck &&
@@ -291,7 +300,7 @@ test_expect_success SYMLINKS 'setup repo with manually 
symlinked dirs and unknow
 '
 
 
-test_expect_success SYMLINKS 'clone repo with symlinked dirs and unknown files 
at objects/' '
+test_expect_success SYMLINKS 'clone repo with symlinked or unknown files at 
objects/' '
        for option in --local --no-hardlinks --shared --dissociate
        do
                git clone $option T T$option || return 1 &&
@@ -300,7 +309,8 @@ test_expect_success SYMLINKS 'clone repo with symlinked 
dirs and unknown files a
                test_cmp T.objects T$option.objects &&
                (
                        cd T$option/.git/objects &&
-                       find . -type f | sort 
>../../../T$option.objects-files.raw
+                       find . -type f | sort 
>../../../T$option.objects-files.raw &&
+                       find . -type l | sort 
>../../../T$option.objects-symlinks.raw
                )
        done &&
 
@@ -314,6 +324,7 @@ test_expect_success SYMLINKS 'clone repo with symlinked 
dirs and unknown files a
        ./Y/Z
        ./Y/Z
        ./a-loose-dir/Z
+       ./an-object
        ./Y/Z
        ./info/packs
        ./pack/pack-Z.idx
@@ -323,13 +334,15 @@ test_expect_success SYMLINKS 'clone repo with symlinked 
dirs and unknown files a
        ./unknown_file
        EOF
 
-       for option in --local --dissociate --no-hardlinks
+       for option in --local --no-hardlinks --dissociate
        do
-               test_cmp expected-files T$option.objects-files.raw.de-sha || 
return 1
+               test_cmp expected-files T$option.objects-files.raw.de-sha || 
return 1 &&
+               test_must_be_empty T$option.objects-symlinks.raw.de-sha || 
return 1
        done &&
 
        echo ./info/alternates >expected-files &&
-       test_cmp expected-files T--shared.objects-files.raw
+       test_cmp expected-files T--shared.objects-files.raw &&
+       test_must_be_empty T--shared.objects-symlinks.raw
 '
 
 test_done
-- 
2.22.0

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