fix: invalid from position (#5287)

Author: ldez

pkg/golinters/gofmt/testdata/gofmt_too_many_empty_lines.go

@@ -0,0 +1,10 @@
+//golangcitest:args -Egofmt
+package testdata
+
+import "fmt"
+
+// want +4 "File is not properly formatted"
+func _() {
+	fmt.Println("foo")
+}
+

pkg/golinters/gofumpt/testdata/gofumpt_too_many_empty_lines.go

@@ -0,0 +1,10 @@
+//golangcitest:args -Egofumpt
+package testdata
+
+import "fmt"
+
+// want +4 "File is not properly formatted"
+func _() {
+	fmt.Println("foo")
+}
+

pkg/golinters/internal/diff.go

@@ -251,7 +251,12 @@ func ExtractDiagnosticFromPatch(
 }
 
 func toDiagnostic(ft *token.File, change Change, adjLine int) analysis.Diagnostic {
-	start := ft.LineStart(change.From + adjLine)
+	from := change.From + adjLine
+	if from > ft.LineCount() {
+		from = ft.LineCount()
+	}
+
+	start := ft.LineStart(from)
 
 	end := goanalysis.EndOfLinePos(ft, change.To+adjLine)
 

pkg/golinters/internal/diff_test.go

@@ -19,6 +19,13 @@ func Test_parse(t *testing.T) {
 		log      logutils.Log
 		expected []Change
 	}{
+		{
+			diff: "delete_last_line.diff",
+			expected: []Change{{
+				From: 10,
+				To:   10,
+			}},
+		},
 		{
 			diff: "delete_only_first_lines.diff",
 			expected: []Change{{

pkg/golinters/internal/testdata/delete_last_line.diff

@@ -0,0 +1,9 @@
+diff --git i/main.go w/main.go
+index ef3cbb7..52a7925 100644
+--- i/main.go
++++ w/main.go
+@@ -7,4 +7,3 @@ import (
+ func main() {
+        fmt.Println("hello world")
+ }
+-