fix: cover more constraint syntax (#198)

SQLite stores the DDL "as-is" in `sqlite_master`. This new regex covers a broader range of valid syntax for constraints.

Author: ThisIsAreku

ddlmod.go

@@ -209,8 +209,12 @@ func (d *ddl) renameTable(dst, src string) error {
 	return nil
 }
 
+func compileConstraintRegexp(name string) *regexp.Regexp {
+	return regexp.MustCompile("^(?i:CONSTRAINT)\\s+[\"`]?" + regexp.QuoteMeta(name) + "[\"`\\s]")
+}
+
 func (d *ddl) addConstraint(name string, sql string) {
-	reg := regexp.MustCompile("^CONSTRAINT [\"`]?" + regexp.QuoteMeta(name) + "[\"` ]")
+	reg := compileConstraintRegexp(name)
 
 	for i := 0; i < len(d.fields); i++ {
 		if reg.MatchString(d.fields[i]) {
@@ -223,7 +227,7 @@ func (d *ddl) addConstraint(name string, sql string) {
 }
 
 func (d *ddl) removeConstraint(name string) bool {
-	reg := regexp.MustCompile("^CONSTRAINT [\"`]?" + regexp.QuoteMeta(name) + "[\"` ]")
+	reg := compileConstraintRegexp(name)
 
 	for i := 0; i < len(d.fields); i++ {
 		if reg.MatchString(d.fields[i]) {
@@ -235,7 +239,7 @@ func (d *ddl) removeConstraint(name string) bool {
 }
 
 func (d *ddl) hasConstraint(name string) bool {
-	reg := regexp.MustCompile("^CONSTRAINT [\"`]?" + regexp.QuoteMeta(name) + "[\"` ]")
+	reg := compileConstraintRegexp(name)
 
 	for _, f := range d.fields {
 		if reg.MatchString(f) {

ddlmod_test.go

@@ -313,6 +313,41 @@ func TestRemoveConstraint(t *testing.T) {
 			success: true,
 			expect:  []string{"`id` integer NOT NULL"},
 		},
+		{
+			name:    "lowercase",
+			fields:  []string{"`id` integer NOT NULL", "constraint `fk_users_notes` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`))"},
+			cName:   "fk_users_notes",
+			success: true,
+			expect:  []string{"`id` integer NOT NULL"},
+		},
+		{
+			name:    "mixed_case",
+			fields:  []string{"`id` integer NOT NULL", "cOnsTraiNT `fk_users_notes` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`))"},
+			cName:   "fk_users_notes",
+			success: true,
+			expect:  []string{"`id` integer NOT NULL"},
+		},
+		{
+			name:    "newline",
+			fields:  []string{"`id` integer NOT NULL", "CONSTRAINT `fk_users_notes`\nFOREIGN KEY (`user_id`) REFERENCES `users`(`id`))"},
+			cName:   "fk_users_notes",
+			success: true,
+			expect:  []string{"`id` integer NOT NULL"},
+		},
+		{
+			name:    "lots_of_newlines",
+			fields:  []string{"`id` integer NOT NULL", "constraint \n    fk_users_notes \n   FOREIGN KEY (`user_id`) REFERENCES `users`(`id`))"},
+			cName:   "fk_users_notes",
+			success: true,
+			expect:  []string{"`id` integer NOT NULL"},
+		},
+		{
+			name:    "no_backtick",
+			fields:  []string{"`id` integer NOT NULL", "CONSTRAINT fk_users_notes FOREIGN KEY (`user_id`) REFERENCES `users`(`id`))"},
+			cName:   "fk_users_notes",
+			success: true,
+			expect:  []string{"`id` integer NOT NULL"},
+		},
 		{
 			name:    "check",
 			fields:  []string{"CONSTRAINT `name_checker` CHECK (`name` <> 'thetadev')", "`id` integer NOT NULL"},