contrib/subtree: Add a test for subtree rebase that loses commits

This test merges an external tree in as a subtree, makes some commits
on top of it and splits it back out.  In the process the added commits
are lost or the rebase aborts with an internal error.  The tests are
marked to expect failure so that we don't forget to fix it.

Signed-off-by: David A. Greene <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: greened

t/t3427-rebase-subtree.sh

@@ -0,0 +1,119 @@
+#!/bin/sh
+
+test_description='git rebase tests for -Xsubtree
+
+This test runs git rebase and tests the subtree strategy.
+'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-rebase.sh
+
+commit_message() {
+	git log --pretty=format:%s -1 "$1"
+}
+
+test_expect_success 'setup' '
+	test_commit README &&
+	mkdir files &&
+	(
+		cd files &&
+		git init &&
+		test_commit master1 &&
+		test_commit master2 &&
+		test_commit master3
+	) &&
+	git fetch files master &&
+	git branch files-master FETCH_HEAD &&
+	git read-tree --prefix=files_subtree files-master &&
+	git checkout -- files_subtree &&
+	tree=$(git write-tree) &&
+	head=$(git rev-parse HEAD) &&
+	rev=$(git rev-parse --verify files-master^0) &&
+	commit=$(git commit-tree -p $head -p $rev -m "Add subproject master" $tree) &&
+	git update-ref HEAD $commit &&
+	(
+		cd files_subtree &&
+		test_commit master4
+	) &&
+	test_commit files_subtree/master5
+'
+
+# FAILURE: Does not preserve master4.
+test_expect_failure 'Rebase -Xsubtree --preserve-merges --onto commit 4' '
+	reset_rebase &&
+	git checkout -b rebase-preserve-merges-4 master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --preserve-merges --onto files-master master &&
+	verbose test "$(commit_message HEAD~)" = "files_subtree/master4"
+'
+
+# FAILURE: Does not preserve master5.
+test_expect_failure 'Rebase -Xsubtree --preserve-merges --onto commit 5' '
+	reset_rebase &&
+	git checkout -b rebase-preserve-merges-5 master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --preserve-merges --onto files-master master &&
+	verbose test "$(commit_message HEAD)" = "files_subtree/master5"
+'
+
+# FAILURE: Does not preserve master4.
+test_expect_failure 'Rebase -Xsubtree --keep-empty --preserve-merges --onto commit 4' '
+	reset_rebase &&
+	git checkout -b rebase-keep-empty-4 master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --keep-empty --preserve-merges --onto files-master master &&
+	verbose test "$(commit_message HEAD~2)" = "files_subtree/master4"
+'
+
+# FAILURE: Does not preserve master5.
+test_expect_failure 'Rebase -Xsubtree --keep-empty --preserve-merges --onto commit 5' '
+	reset_rebase &&
+	git checkout -b rebase-keep-empty-5 master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --keep-empty --preserve-merges --onto files-master master &&
+	verbose test "$(commit_message HEAD~)" = "files_subtree/master5"
+'
+
+# FAILURE: Does not preserve Empty.
+test_expect_failure 'Rebase -Xsubtree --keep-empty --preserve-merges --onto empty commit' '
+	reset_rebase &&
+	git checkout -b rebase-keep-empty-empty master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --keep-empty --preserve-merges --onto files-master master &&
+	verbose test "$(commit_message HEAD)" = "Empty commit"
+'
+
+# FAILURE: fatal: Could not parse object
+test_expect_failure 'Rebase -Xsubtree --onto commit 4' '
+	reset_rebase &&
+	git checkout -b rebase-onto-4 master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --onto files-master master &&
+	verbose test "$(commit_message HEAD~2)" = "files_subtree/master4"
+'
+
+# FAILURE: fatal: Could not parse object
+test_expect_failure 'Rebase -Xsubtree --onto commit 5' '
+	reset_rebase &&
+	git checkout -b rebase-onto-5 master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --onto files-master master &&
+	verbose test "$(commit_message HEAD~)" = "files_subtree/master5"
+'
+# FAILURE: fatal: Could not parse object
+test_expect_failure 'Rebase -Xsubtree --onto empty commit' '
+	reset_rebase &&
+	git checkout -b rebase-onto-empty master &&
+	git filter-branch --prune-empty -f --subdirectory-filter files_subtree &&
+	git commit -m "Empty commit" --allow-empty &&
+	git rebase -Xsubtree=files_subtree --onto files-master master &&
+	verbose test "$(commit_message HEAD)" = "Empty commit"
+'
+
+test_done