Merge branch 'pb/pull-rebase-recurse-submodules'

"git pull --rebase --recurse-submodules" checked for local changes
in a wrong range and failed to run correctly when it should.

* pb/pull-rebase-recurse-submodules:
  pull: check for local submodule modifications with the right range
  t5572: describe '--rebase' tests a little more
  t5572: add notes on a peculiar test
  pull --rebase: compute rebase arguments in separate function

1 files changed, 54 insertions, 2 deletions

diff --git a/t/t5572-pull-submodule.sh b/t/t5572-pull-submodule.sh
index 1d75e3b12b..37fd06b0be 100755
--- a/t/t5572-pull-submodule.sh
+++ b/t/t5572-pull-submodule.sh
@@ -101,7 +101,12 @@ test_expect_success " --[no-]recurse-submodule and submodule.recurse" '
 	test_path_is_file super/sub/merge_strategy_4.t
 '
 
-test_expect_success 'recursive rebasing pull' '
+test_expect_success 'pull --rebase --recurse-submodules (remote superproject submodule changes, local submodule changes)' '
+	# This tests the following scenario :
+	# - local submodule has new commits
+	# - local superproject does not have new commits
+	# - upstream superproject has new commits that change the submodule pointer
+
 	# change upstream
 	test_commit -C child rebase_strategy &&
 	git -C parent submodule update --remote &&
@@ -116,7 +121,10 @@ test_expect_success 'recursive rebasing pull' '
 	test_path_is_file super/sub/local_stuff.t
 '
 
-test_expect_success 'pull rebase recursing fails with conflicts' '
+test_expect_success 'pull --rebase --recurse-submodules fails if both sides record submodule changes' '
+	# This tests the following scenario :
+	# - local superproject has new commits that change the submodule pointer
+	# - upstream superproject has new commits that change the submodule pointer
 
 	# local changes in submodule recorded in superproject:
 	test_commit -C super/sub local_stuff_2 &&
@@ -136,6 +144,50 @@ test_expect_success 'pull rebase recursing fails with conflicts' '
 	test_i18ngrep "locally recorded submodule modifications" err
 '
 
+test_expect_success 'pull --rebase --recurse-submodules (no submodule changes, no fork-point)' '
+	# This tests the following scenario :
+	# - local submodule does not have new commits
+	# - local superproject has new commits that *do not* change the submodule pointer
+	# - upstream superproject has new commits that *do not* change the submodule pointer
+	# - local superproject branch has no fork-point with its remote-tracking counter-part
+
+	# create upstream superproject
+	test_create_repo submodule &&
+	test_commit -C submodule first_in_sub &&
+
+	test_create_repo superprojet &&
+	test_commit -C superprojet first_in_super &&
+	git -C superprojet submodule add ../submodule &&
+	git -C superprojet commit -m "add submodule" &&
+	test_commit -C superprojet third_in_super &&
+
+	# clone superproject
+	git clone --recurse-submodules superprojet superclone &&
+
+	# add commits upstream
+	test_commit -C superprojet fourth_in_super &&
+
+	# create topic branch in clone, not based on any remote-tracking branch
+	git -C superclone checkout -b feat HEAD~1 &&
+	test_commit -C superclone first_on_feat &&
+	git -C superclone pull --rebase --recurse-submodules origin master
+'
+
+# NOTE:
+#
+# This test is particular because there is only a single commit in the upstream superproject
+# 'parent' (which adds the submodule 'a-submodule'). The clone of the superproject
+# ('child') hard-resets its branch to a new root commit with the same tree as the one
+# from the upstream superproject, so that its branch has no merge-base with its
+# remote-tracking counterpart, and then calls 'git pull --recurse-submodules --rebase'.
+# The result is that the local branch is reset to the remote-tracking branch (as it was
+# originally before the hard-reset).
+
+# The only commit in the range generated by 'submodule.c::submodule_touches_in_range' and
+# passed to 'submodule.c::collect_changed_submodules' is the new (regenerated) initial commit,
+# which adds the submodule.
+# However, 'submodule_touches_in_range' does not error (even though this commit adds the submodule)
+# because 'combine-diff.c::diff_tree_combined' returns early, as the initial commit has no parents.
 test_expect_success 'branch has no merge base with remote-tracking counterpart' '
 	rm -rf parent child &&