libopkbuild: Abort on invalid function arguments

Shift arguments and abort instead of returning 125.

Incorrect numbers of function arguments suggest application/library
incompatibilities or serious errors by the application developer.
Either way, the application developer should be made immediately aware
of this (and not allowed to simply not check return values), and
continuing to run and handle any further API calls may be unsafe.

1 files changed, 21 insertions, 46 deletions

diff --git a/lib/control.sh b/lib/control.sh
index 58bf68b..c29d4a0 100644
--- a/lib/control.sh
+++ b/lib/control.sh
@@ -21,15 +21,11 @@ _OB_SUBSTVARS_MAX_DEPTH=50
 
 _ob_parse_control_error()
 {
-	local file=
-	local line_nr=
-	local msg_id=
-	local file_info=
-
 	file="${1}"
 	line_nr="${2}"
 	msg_id="${3}"
-	shift 3
+	shift 3 || _ob_abort
+	local file_info=
 
 	if [ ${line_nr} -eq 0 ]; then
 		file_info="$(printf '%20s' "${file}")"
@@ -61,20 +57,20 @@ _ob_parse_control_error()
 ## @operand user_data  req Data to pass to \fIfield_cb\fP.
 ## @operand req_fields opt Required fields that must appear in the control file.
 ## @operand opt_fields opt Optional fields that may appear in the control file.
-## @return Returns 0 after parsing, or 125 if called with an incorrect number of
-##         arguments.
+## @return Returns 0 after parsing.
 ## @stderr Prints error messages on parse errors.
 ## @pure maybe This function has no side effects.  Whether this function is
 ##             subshell-safe in practice depends on whether \fIfield_cb\fP is
 ##             subshell-safe.
 ob_parse_control()
 {
-	local file=
-	local field_cb=
-	local user_data=
+	local file="${1}"
+	local field_cb="${2}"
+	local user_data="${3}"
+	shift 3 || _ob_abort
+	local check_fields=
 	local req_fields=
 	local opt_fields=
-	local check_fields=
 	local got_fields=
 	local line_nr=
 	local line=
@@ -82,20 +78,11 @@ ob_parse_control()
 	local value=
 	local sep=
 
-	if [ ${#} -eq 3 ]; then
-		file="${1}"
-		field_cb="${2}"
-		user_data="${3}"
-		check_fields='false'
-	elif [ ${#} -eq 5 ]; then
-		file="${1}"
-		field_cb="${2}"
-		user_data="${3}"
-		req_fields=" ${4} "
-		opt_fields=" ${5} "
+	check_fields='false'
+	if [ ${#} -eq 2 ]; then
+		req_fields=" ${1} "
+		opt_fields=" ${2} "
 		check_fields='true'
-	else
-		return 125
 	fi
 
 	got_fields=' '
@@ -195,24 +182,18 @@ ob_parse_control()
 ##                    of uppercase and lowercase Latin letters, digits, and
 ##                    hyphens and must be at least one character long.
 ## @operand value req The value of the substitution variable.
-## @return Returns 0 on success, or 125 if called with an incorrect number of
-##         arguments or if \fIname\fP is empty or contains invalid characters.
+## @return Returns 0 on success, or 1 if \fIname\fP is empty or contains invalid
+##         characters.
 ## @pure no This function sets an internal global variable.
 ob_set_substvar()
 {
-	local name=
-	local value=
-
-	if [ ${#} -eq 2 ]; then
-		name="${1}"
-		value="${2}"
-	else
-		return 125
-	fi
+	local name="${1}"
+	local value="${2}"
+	shift 2 || _ob_abort
 
 	# Convert variable name to uppercase and validate.
 	case "${name}" in *[!A-Za-z0-9-]* | '')
-		return 125
+		return 1
 	esac
 	name="$(tr 'a-z-' 'A-Z_' <<-EOF
 		${name}
@@ -234,13 +215,13 @@ ob_set_substvar()
 ##          \fBob_set_substvar\fP(3) in a string.  The format for variable
 ##          substitutions is \fI${var}\fP, and substitutions can be nested.
 ## @operand string req The string in which to substitute variables.
-## @return Returns 0 on success, 1 on possible recursion, or 125 if called with
-##         an incorrect number of arguments.
+## @return Returns 0 on success or 1 on possible recursion.
 ## @stderr Prints a warning on possible recursion.
 ## @pure yes This function has no side effects.
 ob_substvars()
 {
-	local string=
+	local string="${1}"
+	shift 1 || _ob_abort
 	local depth=
 	local lhs=
 	local name=
@@ -248,12 +229,6 @@ ob_substvars()
 	local old_rhs=
 	local value=
 
-	if [ ${#} -eq 1 ]; then
-		string="${1}"
-	else
-		return 125
-	fi
-
 	# Logic inspired by that of dpkg's Dpkg::Substvars::substvars() subroutine.
 
 	depth=0