Merge pull request #1952 from gaelicWizard/uncle

lib/helpers: new function `_bash-it-find-in-ancestor()`

lib/helpers.bash

@@ -849,3 +849,30 @@ then
     fi
   }
 fi
+
+# `_bash-it-find-in-ancestor` uses the shell's ability to run a function in
+# a subshell to simplify our search to a simple `cd ..` and `[[ -r $1 ]]`
+# without any external dependencies. Let the shell do what it's good at.
+function _bash-it-find-in-ancestor() (
+	about 'searches parents of the current directory for any of the specified file names'
+	group 'helpers'
+	param '*: names of files or folders to search for'
+	returns '0: prints path of closest matching ancestor directory to stdout'
+	returns '1: no match found'
+	returns '2: improper usage of shell builtin' # uncommon
+	example '_bash-it-find-in-ancestor .git .hg'
+	example '_bash-it-find-in-ancestor GNUmakefile Makefile makefile'
+
+	local kin
+	# To keep things simple, we do not search the root dir.
+	while [[ "${PWD}" != '/' ]]; do
+		for kin in "$@"; do
+			if [[ -r "${PWD}/${kin}" ]]; then
+				printf '%s' "${PWD}"
+				return "$?"
+			fi
+		done
+		command cd .. || return "$?"
+	done
+	return 1
+)