format: fix another panic found via fuzzing

A function can have non-nil but empty results, which would lead to a sign.Results.List[-1] panic.
Oiyoo · Apr 3, 2022 · 6105233 · 6105233
1 parent b92582e
commit 6105233
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/format/format.go b/format/format.go
@@ -570,7 +570,7 @@ func (f *fumpter) applyPre(c *astutil.Cursor) {
 					}
 				}
 				handleMultiLine(sign.Params)
-				if sign.Results != nil {
+				if sign.Results != nil && len(sign.Results.List) > 0 {
 					lastResultLine := f.Line(sign.Results.List[len(sign.Results.List)-1].End())
 					isLastResultOnParamClosingLine := sign.Params != nil && lastResultLine == f.Line(sign.Params.Closing)
 					if !isLastResultOnParamClosingLine {

diff --git a/...testdata/fuzz/FuzzFormat/18c862f09f82fe57f536e7ab4b1bd63daecc2cba8189530bb0eb77b8cef6f798 b/...testdata/fuzz/FuzzFormat/18c862f09f82fe57f536e7ab4b1bd63daecc2cba8189530bb0eb77b8cef6f798
@@ -0,0 +1,4 @@
+go test fuzz v1
+string("package A\nfunc A000000000(A000000000000,\nA00000000)(){\"\"}")
+int8(62)
+bool(true)