Merge branch 'dg/subtree-rebase-test' into maint

Add a test to specify the desired behaviour that currently is not
available in "git rebase -Xsubtree=...".

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

Author: gitster

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