Fix #301: find min-required version through -chdir

This commit makes it possible to use `min-required` with the terraform
configuration (including the `required_version` spec) in a subdirectory
as `terraform -chdir=subdir`.

Prior to this commit, this behaviour does not work (`-chdir` cannot be
used with `tfenv`'s `terraform` wrapper & `min-required` version)
because `tfenv` expects to find the configuration in `$PWD`.

Author: OJFord

lib/tfenv-exec.sh

@@ -3,6 +3,17 @@
 set -uo pipefail;
 
 function tfenv-exec() {
+  for _arg in ${@:1}; do
+    if [[ "$_arg" == -chdir=* ]]; then
+      log 'debug' "Found -chdir arg: ${_arg#-chdir=}"
+      export TFENV_DIR="${PWD}/${_arg#-chdir=}";
+      break;
+    else
+      export TFENV_DIR="${PWD}";
+    fi;
+    log 'info' "Set TFENV_DIR to $TFENV_DIR"
+  done;
+
   log 'debug' 'Getting version from tfenv-version-name';
   TFENV_VERSION="$(tfenv-version-name)" \
   && log 'debug' "TFENV_VERSION is ${TFENV_VERSION}" \

lib/tfenv-min-required.sh

@@ -3,7 +3,7 @@
 set -uo pipefail;
 
 function tfenv-min-required() {
-  local path="${1:-.}";
+  local path="${1:-${TFENV_DIR:-.}}";
 
   local versions="$( echo $(cat ${path}/{*.tf,*.tf.json} 2>/dev/null | grep -Eh '^\s*[^#]*\s*required_version') | grep -o '[~=!<>]\{0,2\}\s*\([0-9]\+\.\?\)\{2,3\}\(-[a-z]\+[0-9]\+\)\?')";