use: Show stack trace when an import fails

Author: mbland

lib/internal/use

@@ -90,14 +90,17 @@ for __go_module_name in "$@"; do
       __go_module_file="$_GO_SCRIPTS_DIR/lib/$__go_module_name"
 
       if [[ ! -f "$__go_module_file" ]]; then
-        @go.printf "ERROR: Unknown module: $__go_module_name\n" >&2
+        @go.printf 'ERROR: Module %s not found at:\n' "$__go_module_name" >&2
+        @go.print_stack_trace omit_caller >&2
         exit 1
       fi
     fi
   fi
 
   if ! . "$__go_module_file"; then
-    @go.printf "ERROR: Module import failed for: $__go_module_file\n" >&2
+    @go.printf 'ERROR: Failed to import %s module from %s at:\n' \
+      "$__go_module_name" "$__go_module_file" >&2
+    @go.print_stack_trace omit_caller >&2
     exit 1
   fi
 done

tests/modules/use.bats

@@ -45,7 +45,11 @@ teardown() {
 
 @test "$SUITE: error if nonexistent module specified" {
   run "$TEST_GO_SCRIPT" 'bogus-test-module'
-  assert_failure 'ERROR: Unknown module: bogus-test-module'
+
+  local expected=('ERROR: Module bogus-test-module not found at:'
+    "  $TEST_GO_SCRIPT:3 main")
+  local IFS=$'\n'
+  assert_failure "${expected[*]}"
 }
 
 @test "$SUITE: import modules successfully" {
@@ -73,12 +77,33 @@ teardown() {
 }
 
 @test "$SUITE: error if module contains errors" {
-  echo "This is a totally broken module." >> "${TEST_MODULES[1]}"
+  local module="${IMPORTS[1]}"
+  local module_file="${TEST_MODULES[2]}"
+
+  echo "This is a totally broken module." > "$module_file"
+  run "$TEST_GO_SCRIPT" "${IMPORTS[@]}"
+
+  local expected=("${IMPORTS[0]##*/} loaded"
+    "$module_file: line 1: This: command not found"
+    "ERROR: Failed to import $module module from $module_file at:"
+    "  $TEST_GO_SCRIPT:3 main")
+  local IFS=$'\n'
+  assert_failure "${expected[*]}"
+}
+
+@test "$SUITE: error if module returns an error" {
+  local module="${IMPORTS[1]}"
+  local module_file="${TEST_MODULES[2]}"
+  local error_message='These violent delights have violent ends...'
+
+  echo "echo '$error_message' >&2" > "$module_file"
+  echo "return 1" >> "$module_file"
   run "$TEST_GO_SCRIPT" "${IMPORTS[@]}"
 
   local expected=("${IMPORTS[0]##*/} loaded"
-    "${TEST_MODULES[1]}: line 2: This: command not found"
-    "ERROR: Module import failed for: ${TEST_MODULES[1]}")
+    "$error_message"
+    "ERROR: Failed to import $module module from $module_file at:"
+    "  $TEST_GO_SCRIPT:3 main")
   local IFS=$'\n'
   assert_failure "${expected[*]}"
 }