Collect merge-related tests to t64xx

The tests for the merge machinery are spread over several places.
Collect them into t64xx for simplicity.  Some notes:

t60[234]*.sh:
  Merge tests started in t602*, overgrew bisect and remote tracking
  tests in t6030, t6040, and t6041, and nearly overtook replace tests
  in t6050.  This made picking out relevant tests that I wanted to run
  in a tighter loop slightly more annoying for years.

t303*.sh:
  These started out as tests for the 'merge-recursive' toplevel command,
  but did not restrict to that and had lots of overlap with the
  underlying merge machinery.
t7405, t7613:
  submodule-specific merge logic started out in submodule.c but was
  moved to merge-recursive.c in commit 18cfc08866 ("submodule.c: move
  submodule merging to merge-recursive.c", 2018-05-15).  Since these
  tests are about the logic found in the merge machinery, moving these
  tests to be with the merge tests makes sense.

t7607, t7609:
  Having tests spread all over the place makes it more likely that
  additional tests related to a certain piece of logic grow in all those
  other places.  Much like t303*.sh, these two tests were about the
  underlying merge machinery rather than outer levels.

Tests that were NOT moved:

t76[01]*.sh:
  Other than the four tests mentioned above, the remaining tests in
  t76[01]*.sh are related to non-recursive merge strategies, parameter
  parsing, and other stuff associated with the highlevel builtin/merge.c
  rather than the recursive merge machinery.

t3[45]*.sh:
  The rebase testcases in t34*.sh also test the merge logic pretty
  heavily; sometimes changes I make only trigger failures in the rebase
  tests.  The rebase tests are already nicely coupled together, though,
  and I didn't want to mess that up.  Similar comments apply for the
  cherry-pick tests in t35*.sh.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 195 insertions, 0 deletions

diff --git a/t/t6436-merge-overwrite.sh b/t/t6436-merge-overwrite.sh
new file mode 100755
index 0000000000..dd8ab7ede1
--- /dev/null
+++ b/t/t6436-merge-overwrite.sh
@@ -0,0 +1,195 @@
+#!/bin/sh
+
+test_description='git-merge
+
+Do not overwrite changes.'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit c0 c0.c &&
+	test_commit c1 c1.c &&
+	test_commit c1a c1.c "c1 a" &&
+	git reset --hard c0 &&
+	test_commit c2 c2.c &&
+	git reset --hard c0 &&
+	mkdir sub &&
+	echo "sub/f" > sub/f &&
+	mkdir sub2 &&
+	echo "sub2/f" > sub2/f &&
+	git add sub/f sub2/f &&
+	git commit -m sub &&
+	git tag sub &&
+	echo "VERY IMPORTANT CHANGES" > important
+'
+
+test_expect_success 'will not overwrite untracked file' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	test_must_fail git merge c2 &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c2.c
+'
+
+test_expect_success 'will overwrite tracked file' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	git add c2.c &&
+	git commit -m important &&
+	git checkout c2
+'
+
+test_expect_success 'will not overwrite new file' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	git add c2.c &&
+	test_must_fail git merge c2 &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c2.c
+'
+
+test_expect_success 'will not overwrite staged changes' '
+	git reset --hard c1 &&
+	cp important c2.c &&
+	git add c2.c &&
+	rm c2.c &&
+	test_must_fail git merge c2 &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	git checkout c2.c &&
+	test_cmp important c2.c
+'
+
+test_expect_success 'will not overwrite removed file' '
+	git reset --hard c1 &&
+	git rm c1.c &&
+	git commit -m "rm c1.c" &&
+	cp important c1.c &&
+	test_must_fail git merge c1a &&
+	test_cmp important c1.c
+'
+
+test_expect_success 'will not overwrite re-added file' '
+	git reset --hard c1 &&
+	git rm c1.c &&
+	git commit -m "rm c1.c" &&
+	cp important c1.c &&
+	git add c1.c &&
+	test_must_fail git merge c1a &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c1.c
+'
+
+test_expect_success 'will not overwrite removed file with staged changes' '
+	git reset --hard c1 &&
+	git rm c1.c &&
+	git commit -m "rm c1.c" &&
+	cp important c1.c &&
+	git add c1.c &&
+	rm c1.c &&
+	test_must_fail git merge c1a &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	git checkout c1.c &&
+	test_cmp important c1.c
+'
+
+test_expect_success 'will not overwrite unstaged changes in renamed file' '
+	git reset --hard c1 &&
+	git mv c1.c other.c &&
+	git commit -m rename &&
+	cp important other.c &&
+	test_must_fail git merge c1a >out &&
+	test_i18ngrep "Refusing to lose dirty file at other.c" out &&
+	test_path_is_file other.c~HEAD &&
+	test $(git hash-object other.c~HEAD) = $(git rev-parse c1a:c1.c) &&
+	test_cmp important other.c
+'
+
+test_expect_success 'will not overwrite untracked subtree' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	mkdir -p sub/f &&
+	cp important sub/f/important &&
+	test_must_fail git merge sub &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important sub/f/important
+'
+
+cat >expect <<\EOF
+error: The following untracked working tree files would be overwritten by merge:
+	sub
+	sub2
+Please move or remove them before you merge.
+Aborting
+EOF
+
+test_expect_success 'will not overwrite untracked file in leading path' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	cp important sub &&
+	cp important sub2 &&
+	test_must_fail git merge sub 2>out &&
+	test_i18ncmp out expect &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important sub &&
+	test_cmp important sub2 &&
+	rm -f sub sub2
+'
+
+test_expect_success SYMLINKS 'will not overwrite untracked symlink in leading path' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	mkdir sub2 &&
+	ln -s sub2 sub &&
+	test_must_fail git merge sub &&
+	test_path_is_missing .git/MERGE_HEAD
+'
+
+test_expect_success 'will not be confused by symlink in leading path' '
+	git reset --hard c0 &&
+	rm -rf sub &&
+	test_ln_s_add sub2 sub &&
+	git commit -m ln &&
+	git checkout sub
+'
+
+cat >expect <<\EOF
+error: Untracked working tree file 'c0.c' would be overwritten by merge.
+fatal: read-tree failed
+EOF
+
+test_expect_success 'will not overwrite untracked file on unborn branch' '
+	git reset --hard c0 &&
+	git rm -fr . &&
+	git checkout --orphan new &&
+	cp important c0.c &&
+	test_must_fail git merge c0 2>out &&
+	test_i18ncmp out expect
+'
+
+test_expect_success 'will not overwrite untracked file on unborn branch .git/MERGE_HEAD sanity etc.' '
+	test_when_finished "rm c0.c" &&
+	test_path_is_missing .git/MERGE_HEAD &&
+	test_cmp important c0.c
+'
+
+test_expect_success 'failed merge leaves unborn branch in the womb' '
+	test_must_fail git rev-parse --verify HEAD
+'
+
+test_expect_success 'set up unborn branch and content' '
+	git symbolic-ref HEAD refs/heads/unborn &&
+	rm -f .git/index &&
+	echo foo > tracked-file &&
+	git add tracked-file &&
+	echo bar > untracked-file
+'
+
+test_expect_success 'will not clobber WT/index when merging into unborn' '
+	git merge master &&
+	grep foo tracked-file &&
+	git show :tracked-file >expect &&
+	grep foo expect &&
+	grep bar untracked-file
+'
+
+test_done