Merge branch 'cw/worktree-relative'

An extra worktree attached to a repository points at each other to
allow finding the repository from the worktree and vice versa
possible.  Turn this linkage to relative paths.

* cw/worktree-relative:
  worktree: add test for path handling in linked worktrees
  worktree: link worktrees with relative paths
  worktree: refactor infer_backlink() to use *strbuf
  worktree: repair copied repository and linked worktrees

Documentation/git-worktree.txt

@@ -157,7 +157,7 @@ will reestablish the connection. If multiple linked worktrees are moved,
 running `repair` from any worktree with each tree's new `<path>` as an
 argument, will reestablish the connection to all the specified paths.
 +
-If both the main worktree and linked worktrees have been moved manually,
+If both the main worktree and linked worktrees have been moved or copied manually,
 then running `repair` in the main worktree and specifying the new `<path>`
 of each linked worktree will reestablish all connections in both
 directions.

builtin/worktree.c

@@ -414,7 +414,8 @@ static int add_worktree(const char *path, const char *refname,
 			const struct add_opts *opts)
 {
 	struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
-	struct strbuf sb = STRBUF_INIT, realpath = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT, sb_tmp = STRBUF_INIT;
+	struct strbuf sb_path_realpath = STRBUF_INIT, sb_repo_realpath = STRBUF_INIT;
 	const char *name;
 	struct strvec child_env = STRVEC_INIT;
 	unsigned int counter = 0;
@@ -490,11 +491,10 @@ static int add_worktree(const char *path, const char *refname,
 
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
-	strbuf_realpath(&realpath, sb_git.buf, 1);
-	write_file(sb.buf, "%s", realpath.buf);
-	strbuf_realpath(&realpath, repo_get_common_dir(the_repository), 1);
-	write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
-		   realpath.buf, name);
+	strbuf_realpath(&sb_path_realpath, path, 1);
+	strbuf_realpath(&sb_repo_realpath, sb_repo.buf, 1);
+	write_file(sb.buf, "%s/.git", relative_path(sb_path_realpath.buf, sb_repo_realpath.buf, &sb_tmp));
+	write_file(sb_git.buf, "gitdir: %s", relative_path(sb_repo_realpath.buf, sb_path_realpath.buf, &sb_tmp));
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
@@ -578,11 +578,13 @@ static int add_worktree(const char *path, const char *refname,
 
 	strvec_clear(&child_env);
 	strbuf_release(&sb);
+	strbuf_release(&sb_tmp);
 	strbuf_release(&symref);
 	strbuf_release(&sb_repo);
+	strbuf_release(&sb_repo_realpath);
 	strbuf_release(&sb_git);
+	strbuf_release(&sb_path_realpath);
 	strbuf_release(&sb_name);
-	strbuf_release(&realpath);
 	free_worktree(wt);
 	return ret;
 }

setup.c

@@ -2420,7 +2420,7 @@ static void separate_git_dir(const char *git_dir, const char *git_link)
 
 		if (rename(src, git_dir))
 			die_errno(_("unable to move %s to %s"), src, git_dir);
-		repair_worktrees(NULL, NULL);
+		repair_worktrees_after_gitdir_move(src);
 	}
 
 	write_file(git_link, "gitdir: %s", git_dir);

t/t2401-worktree-prune.sh

@@ -120,4 +120,23 @@ test_expect_success 'prune duplicate (main/linked)' '
 	! test -d .git/worktrees/wt
 '
 
+test_expect_success 'not prune proper worktrees when run inside linked worktree' '
+	test_when_finished rm -rf repo wt_ext &&
+	git init repo &&
+	(
+	    cd repo &&
+	    echo content >file &&
+	    git add file &&
+	    git commit -m msg &&
+	    git worktree add ../wt_ext &&
+	    git worktree add wt_int &&
+	    cd wt_int &&
+	    git worktree prune -v >out &&
+	    test_must_be_empty out &&
+	    cd ../../wt_ext &&
+	    git worktree prune -v >out &&
+	    test_must_be_empty out
+	)
+'
+
 test_done

t/t2406-worktree-repair.sh

@@ -197,4 +197,23 @@ test_expect_success 'repair moved main and linked worktrees' '
 	test_cmp expect-gitfile sidemoved/.git
 '
 
+test_expect_success 'repair copied main and linked worktrees' '
+	test_when_finished "rm -rf orig dup" &&
+	mkdir -p orig &&
+	git -C orig init main &&
+	test_commit -C orig/main nothing &&
+	git -C orig/main worktree add ../linked &&
+	cp orig/main/.git/worktrees/linked/gitdir orig/main.expect &&
+	cp orig/linked/.git orig/linked.expect &&
+	cp -R orig dup &&
+	sed "s,orig/linked/\.git$,dup/linked/.git," orig/main.expect >dup/main.expect &&
+	sed "s,orig/main/\.git/worktrees/linked$,dup/main/.git/worktrees/linked," \
+		orig/linked.expect >dup/linked.expect &&
+	git -C dup/main worktree repair ../linked &&
+	test_cmp orig/main.expect orig/main/.git/worktrees/linked/gitdir &&
+	test_cmp orig/linked.expect orig/linked/.git &&
+	test_cmp dup/main.expect dup/main/.git/worktrees/linked/gitdir &&
+	test_cmp dup/linked.expect dup/linked/.git
+'
+
 test_done

t/t2408-worktree-relative.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='test worktrees linked with relative paths'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+test_expect_success 'links worktrees with relative paths' '
+	test_when_finished rm -rf repo &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		git worktree add wt1 &&
+		echo "../../../wt1/.git" >expected_gitdir &&
+		cat .git/worktrees/wt1/gitdir >actual_gitdir &&
+		echo "gitdir: ../.git/worktrees/wt1" >expected_git &&
+		cat wt1/.git >actual_git &&
+		test_cmp expected_gitdir actual_gitdir &&
+		test_cmp expected_git actual_git
+	)
+'
+
+test_expect_success 'move repo without breaking relative internal links' '
+	test_when_finished rm -rf repo moved &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		git worktree add wt1 &&
+		cd .. &&
+		mv repo moved &&
+		cd moved/wt1 &&
+		git status >out 2>err &&
+		test_must_be_empty err
+	)
+'
+
+test_done