Repository: tomarrell/lbadd (go)
Issue: parser: statement ending in whitespace causes panic
Statements ending in whitespaces, such as `SELECT ` cause a panic.
```
panic: runtime error: index out of range [7] with length 7 [recovered]
        panic: runtime error: index out of range [7] with length 7

goroutine 19 [running]:
testing.tRunner.func1(0xc0000f2e00)
        /usr/local/go/src/testing/testing.go:874 +0x3a3
panic(0x13282c0, 0xc0000167c0)
        /usr/local/go/src/runtime/panic.go:679 +0x1b2
github.com/tomarrell/lbadd/internal/parser/scanner.(*ruleBasedScanner).ConsumeRune(0xc0000ee880)
        /Users/tsatke/Development/private/github.com/tomarrell/lbadd/internal/parser/scanner/rule_based_scanner.go:154 +0x77
github.com/tomarrell/lbadd/internal/parser/scanner.(*ruleBasedScanner).applyRule(0xc0000ee880, 0x13b251a, 0x12e7ae0)
        /Users/tsatke/Development/private/github.com/tomarrell/lbadd/internal/parser/scanner/rule_based_scanner.go:99 +0x13c
github.com/tomarrell/lbadd/internal/parser/scanner.(*ruleBasedScanner).computeNext(0xc0000ee880, 0x0, 0xc000113b01)
        /Users/tsatke/Development/private/github.com/tomarrell/lbadd/internal/parser/scanner/rule_based_scanner.go:84 +0x6a
github.com/tomarrell/lbadd/internal/parser/scanner.(*ruleBasedScanner).Peek(...)
        /Users/tsatke/Development/private/github.com/tomarrell/lbadd/internal/parser/scanner/rule_based_scanner.go:61
github.com/tomarrell/lbadd/internal/parser/scanner.(*ruleBasedScanner).Next(0xc0000ee880, 0x12e7ae0, 0x13b251a)
        /Users/tsatke/Development/private/github.com/tomarrell/lbadd/internal/parser/scanner/rule_based_scanner.go:54 +0x78
github.com/tomarrell/lbadd/internal/parser/scanner.TestRuleBasedSannerStatementEndingInWhitespace(0xc0000f2e00)
        /Users/tsatke/Development/private/github.com/tomarrell/lbadd/internal/parser/scanner/rule_based_scanner_test.go:191 +0x260
testing.tRunner(0xc0000f2e00, 0x1368268)
        /usr/local/go/src/testing/testing.go:909 +0xc9
created by testing.(*T).Run
        /usr/local/go/src/testing/testing.go:960 +0x350
FAIL    github.com/tomarrell/lbadd/internal/parser/scanner      0.018s
```
Pull request description: Fix #64

Patch:
diff --git a/internal/parser/scanner/rule_based_scanner.go b/internal/parser/scanner/rule_based_scanner.go
index 4c44692..003a456 100644
--- a/internal/parser/scanner/rule_based_scanner.go
+++ b/internal/parser/scanner/rule_based_scanner.go
@@ -76,11 +76,11 @@ func (s *ruleBasedScanner) done() bool {
 }
 
 func (s *ruleBasedScanner) computeNext() token.Token {
+	s.drainWhitespace()
+
 	if s.done() {
 		return s.eof()
 	}
-
-	s.drainWhitespace()
 	return s.applyRule()
 }
 


Test patch:
diff --git a/internal/parser/scanner/rule_based_scanner_test.go b/internal/parser/scanner/rule_based_scanner_test.go
index 09b875d..fb7f354 100644
--- a/internal/parser/scanner/rule_based_scanner_test.go
+++ b/internal/parser/scanner/rule_based_scanner_test.go
@@ -180,3 +180,14 @@ func _TestRuleBasedScannerWithRuleset(input string, ruleset ruleset.Ruleset, wan
 		}
 	}
 }
+
+func TestRuleBasedSannerStatementEndingInWhitespace(t *testing.T) {
+	assert := assert.New(t)
+
+	stmt := "SELECT "
+	sc := NewRuleBased([]rune(stmt), ruleset.Default)
+	next := sc.Next()
+	assert.Equal(token.KeywordSelect, next.Type())
+	eof := sc.Next()
+	assert.Equal(token.EOF, eof.Type())
+}