populate: check the hooks and submodules of Git work trees

git submodule update uses the .git of a submodule as it finds it in the
work tree: a repository of its own, with configuration that runs
commands, or a file naming a repository elsewhere.  So git_problems
also requires each .git below the work tree to be a file naming a
repository in .git/modules.  And it refuses hooks in .git/hooks, which
populate's Git doesn't run, but Nix's does, writing the lock file of a
flake in a git source.  It's a shell function now, taking the work tree
at run time, so drawing inputs can use it too.

git-submodule plants a submodule's .git in the work tree: a repository
of its own whose configuration names a filter, and a file naming a
repository elsewhere.  The fixture withsub has gitsrc as its submodule
sub.

2 files changed, 77 insertions, 0 deletions

diff --git a/tests/fixtures.sh b/tests/fixtures.sh
index ccd55a0..85701a1 100755
--- a/tests/fixtures.sh
+++ b/tests/fixtures.sh
@@ -307,6 +307,23 @@ mkdir /fixtures/git
 git clone -q --bare /fixtures/gitsrc /fixtures/git/gitsrc.git
 git -C /fixtures/git/gitsrc.git config uploadpack.allowReachableSHA1InWant true
 
+# withsub: a Git repository with gitsrc as its submodule sub, served by git
+# daemon like gitsrc, which the tests reach as git://deployer/gitsrc.git.
+mkdir /fixtures/withsub
+cat > /fixtures/withsub/.gitmodules <<'GIT'
+[submodule "sub"]
+	path = sub
+	url = git://deployer/gitsrc.git
+GIT
+(
+  cd /fixtures/withsub
+  git init -q -b master
+  git update-index --add --cacheinfo 160000,"$git_head",sub
+  git add .gitmodules
+  git commit -q -m withsub
+)
+git clone -q --bare /fixtures/withsub /fixtures/git/withsub.git
+
 # pass: password stores with x/a, without and with Git.
 if ! gpg --list-secret-keys spam@krebsco.de >/dev/null 2>&1; then
   gpg --batch --passphrase '' --quick-gen-key spam@krebsco.de default default never
diff --git a/tests/scenarios.nix b/tests/scenarios.nix
index 8093e02..5d08e2e 100644
--- a/tests/scenarios.nix
+++ b/tests/scenarios.nix
@@ -2104,6 +2104,66 @@ assert !(krops.isLocalTarget (targets.remote "/"));
         }
       ];
     }))
+    # A Git work tree whose submodule's .git, which Git uses as it finds it,
+    # isn't the gitfile git clone made, naming the repository in
+    # .git/modules: a repository of its own, whose configuration names a
+    # command, and a gitfile naming a repository elsewhere.
+    (s "git-submodule" (let
+      elsewhere = "/var/krops-elsewhere";
+      url = dirOf gitUrl + "/withsub.git";
+      git = reclone: { x.git = { inherit url reclone; ref = "master"; }; };
+      untouched = ''
+        test ! -e ${elsewhere}/ran || fail "a command in a .git directory ran"
+        expect_eq "HEAD elsewhere" "$(git -C ${elsewhere}/repo rev-parse HEAD)" ${gitFirst}
+      '';
+    in {
+      isolate = true;
+      prepare = ''
+        rm -fR ${elsewhere}
+        git clone -q ${gitUrl} ${elsewhere}/repo
+        git -C ${elsewhere}/repo checkout -q ${gitFirst}
+      '';
+      phases = [
+        {
+          sources = git false;
+          check = untouched + ''
+            expect_eq "sub HEAD" "$(git -C "$T"/x/sub rev-parse HEAD)" ${gitHead}
+          '';
+          mutate = ''
+            rm "$T"/x/sub/.git
+            cp -R "$T"/x/.git/modules/sub "$T"/x/sub/.git
+            git config --file "$T"/x/sub/.git/config --unset core.worktree
+            git config --file "$T"/x/sub/.git/config \
+                filter.x.smudge "touch ${elsewhere}/ran; cat"
+            echo '* filter=x' > "$T"/x/sub/.git/info/attributes
+            git -C "$T"/x/sub update-ref --no-deref HEAD ${gitFirst}
+            git -C "$T"/x/sub read-tree ${gitFirst}
+            rm "$T"/x/sub/two
+          '';
+        }
+        {
+          sources = git false;
+          expect.fail = "error: populate doesn't use the Git work tree";
+          check = untouched;
+          mutate = ''
+            rm -fR "$T"/x/sub
+            mkdir "$T"/x/sub
+            echo gitdir: ${elsewhere}/repo/.git > "$T"/x/sub/.git
+          '';
+        }
+        {
+          sources = git false;
+          expect.fail = "error: populate doesn't use the Git work tree";
+          check = untouched;
+        }
+        {
+          sources = git true;
+          check = untouched + ''
+            expect_eq "sub HEAD" "$(git -C "$T"/x/sub rev-parse HEAD)" ${gitHead}
+          '';
+        }
+      ];
+    }))
     # A ref that git fetch would take for an option: --upload-pack runs a
     # command where the repository is local.
     (s "git-ref-option" (let