@@ -146,6 +146,46 @@ refer to linkgit:gitignore[5] for details. For convenience:
 	This is the same as `gitdir` except that matching is done
 	case-insensitively (e.g. on case-insensitive file systems)
 
+`worktree`::
+	The data that follows the keyword `worktree` and a colon is used as a
+	glob pattern. If the working directory of the current worktree matches
+	the pattern, the include condition is met.
++
+The worktree location is the path where files are checked out (as returned
+by `git rev-parse --show-toplevel`). This is different from `gitdir`, which
+matches the `.git` directory path. In a linked worktree, the worktree path
+is the directory where that worktree's files are located, not the main
+repository's `.git` directory.
++
+The pattern uses the same glob syntax as `gitdir` (including `~/`, `./`,
+`**/`, and trailing-`/` prefix matching). This condition will never match
+in a bare repository (which has no worktree).
++
+This is useful when you want to apply configuration based on where the
+working tree is located on the filesystem. For example, a contributor who
+works on the same project both personally and as an employee can use
+different `user.name` and `user.email` values depending on which directory
+the worktree is checked out under:
++
+----
+[includeIf "worktree:/home/user/work/"]
+    path = ~/.config/git/work.inc
+[includeIf "worktree:/home/user/personal/"]
+    path = ~/.config/git/personal.inc
+----
++
+While `extensions.worktreeConfig` (see linkgit:git-worktree[1]) also supports
+per-worktree configuration, it stores the config inside each repository's
+`.git/config.worktree` file and requires running `git config --worktree`
+inside each worktree individually. In contrast, `includeIf "worktree:..."`
+can be set once in a global or system-level configuration file (e.g.
+`~/.config/git/config`) and applies to all repositories at once based on
+their worktree location.
+
+`worktree/i`::
+	This is the same as `worktree` except that matching is done
+	case-insensitively (e.g. on case-insensitive file systems)
+
 `onbranch`::
 	The data that follows the keyword `onbranch` and a colon is taken to be a
 	pattern with standard globbing wildcards and two additional

@@ -244,6 +284,14 @@ Example
 [includeIf "gitdir:~/to/group/"]
 	path = /path/to/foo.inc
 
+; include if the worktree is at /path/to/project-build
+[includeIf "worktree:/path/to/project-build"]
+	path = build-config.inc
+
+; include for all worktrees inside /path/to/group
+[includeIf "worktree:/path/to/group/"]
+	path = group-config.inc
+
 ; relative paths are always relative to the including
 ; file (if the condition is true); their location is not
 ; affected by the condition

@@ -400,6 +400,12 @@ static int include_condition_is_true(const struct key_value_info *kvi,
 		return include_by_path(kvi, opts->git_dir, cond, cond_len, 0);
 	else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
 		return include_by_path(kvi, opts->git_dir, cond, cond_len, 1);
+	else if (skip_prefix_mem(cond, cond_len, "worktree:", &cond, &cond_len))
+		return include_by_path(kvi, inc->repo ? repo_get_work_tree(inc->repo) : NULL,
+				       cond, cond_len, 0);
+	else if (skip_prefix_mem(cond, cond_len, "worktree/i:", &cond, &cond_len))
+		return include_by_path(kvi, inc->repo ? repo_get_work_tree(inc->repo) : NULL,
+				       cond, cond_len, 1);
 	else if (skip_prefix_mem(cond, cond_len, "onbranch:", &cond, &cond_len))
 		return include_by_branch(inc, cond, cond_len);
 	else if (skip_prefix_mem(cond, cond_len, "hasconfig:remote.*.url:", &cond,

@@ -396,4 +396,130 @@ test_expect_success 'onbranch without repository but explicit nonexistent Git di
 	test_must_fail nongit git --git-dir=nonexistent config get foo.bar
 '
 
+# worktree: conditional include tests
+
+test_expect_success 'conditional include, worktree bare repo' '
+	git init --bare wt-bare &&
+	(
+		cd wt-bare &&
+		echo "[includeIf \"worktree:/\"]path=bar-bare" >>config &&
+		echo "[test]wtbare=1" >bar-bare &&
+		test_must_fail git config test.wtbare
+	)
+'
+
+test_expect_success 'conditional include, worktree multiple worktrees' '
+	git init wt-multi &&
+	(
+		cd wt-multi &&
+		test_commit initial &&
+		git worktree add -b linked-branch ../wt-linked HEAD &&
+		git worktree add -b prefix-branch ../wt-prefix/linked HEAD
+	) &&
+	wt_main="$(cd wt-multi && pwd)" &&
+	wt_linked="$(cd wt-linked && pwd)" &&
+	wt_prefix_parent="$(cd wt-prefix && pwd)" &&
+	cat >>wt-multi/.git/config <<-EOF &&
+	[includeIf "worktree:$wt_main"]
+		path = main-config
+	[includeIf "worktree:$wt_linked"]
+		path = linked-config
+	[includeIf "worktree:$wt_prefix_parent/"]
+		path = prefix-config
+	EOF
+	echo "[test]mainvar=main" >wt-multi/.git/main-config &&
+	echo "[test]linkedvar=linked" >wt-multi/.git/linked-config &&
+	echo "[test]prefixvar=prefix" >wt-multi/.git/prefix-config &&
+	echo main >expect &&
+	git -C wt-multi config test.mainvar >actual &&
+	test_cmp expect actual &&
+	test_must_fail git -C wt-multi config test.linkedvar &&
+	test_must_fail git -C wt-multi config test.prefixvar &&
+	echo linked >expect &&
+	git -C wt-linked config test.linkedvar >actual &&
+	test_cmp expect actual &&
+	test_must_fail git -C wt-linked config test.mainvar &&
+	test_must_fail git -C wt-linked config test.prefixvar &&
+	echo prefix >expect &&
+	git -C wt-prefix/linked config test.prefixvar >actual &&
+	test_cmp expect actual &&
+	test_must_fail git -C wt-prefix/linked config test.mainvar &&
+	test_must_fail git -C wt-prefix/linked config test.linkedvar
+'
+
+test_expect_success SYMLINKS 'conditional include, worktree resolves symlinks' '
+	mkdir real-wt &&
+	ln -s real-wt link-wt &&
+	git init link-wt/repo &&
+	(
+		cd link-wt/repo &&
+		# repo->worktree resolves symlinks, so use real path in pattern
+		echo "[includeIf \"worktree:**/real-wt/repo\"]path=bar-link" >>.git/config &&
+		echo "[test]wtlink=2" >.git/bar-link &&
+		echo 2 >expect &&
+		git config test.wtlink >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success !CASE_INSENSITIVE_FS 'conditional include, worktree, case sensitive' '
+	git init wt-case &&
+	(
+		cd wt-case &&
+		test_commit initial &&
+		wt_path="$(pwd)" &&
+		wt_upper=$(echo "$wt_path" | tr a-z A-Z) &&
+		echo "[includeIf \"worktree:$wt_upper\"]path=case-inc" >>.git/config &&
+		echo "[test]wtcase=1" >.git/case-inc &&
+		test_must_fail git config test.wtcase
+	)
+'
+
+test_expect_success 'conditional include, worktree, icase' '
+	git init wt-icase &&
+	(
+		cd wt-icase &&
+		test_commit initial &&
+		wt_path="$(pwd)" &&
+		wt_upper=$(echo "$wt_path" | tr a-z A-Z) &&
+		echo "[includeIf \"worktree/i:$wt_upper\"]path=icase-inc" >>.git/config &&
+		echo "[test]wticase=1" >.git/icase-inc &&
+		echo 1 >expect &&
+		git config test.wticase >actual &&
+		test_cmp expect actual
+	)
+'
+
+# The "worktree" condition cannot match during early config reading
+# because the repository object is not yet fully initialized and
+# repo_get_work_tree() returns NULL.
+test_expect_success 'conditional include, worktree does not match in early config' '
+	git init wt-early &&
+	(
+		cd wt-early &&
+		test_commit initial &&
+		wt_path="$(pwd)" &&
+		echo "[includeIf \"worktree:$wt_path\"]path=early-inc" >>.git/config &&
+		echo "[test]wtearly=1" >.git/early-inc &&
+		test-tool config read_early_config test.wtearly >actual &&
+		test_must_be_empty actual
+	)
+'
+
+test_expect_success 'conditional include, worktree without repository' '
+	test_when_finished "rm -f .gitconfig config.inc" &&
+	git config set -f .gitconfig "includeIf.worktree:**.path" config.inc &&
+	git config set -f config.inc foo.bar baz &&
+	git config get foo.bar &&
+	test_must_fail nongit git config get foo.bar
+'
+
+test_expect_success 'conditional include, worktree without repository but explicit nonexistent Git directory' '
+	test_when_finished "rm -f .gitconfig config.inc" &&
+	git config set -f .gitconfig "includeIf.worktree:**.path" config.inc &&
+	git config set -f config.inc foo.bar baz &&
+	git config get foo.bar &&
+	test_must_fail nongit git --git-dir=nonexistent config get foo.bar
+'
+
 test_done