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| author | Rob Pike <r@golang.org> | 2019-10-24 18:22:43 +1100 |
|---|---|---|
| committer | Rob Pike <r@golang.org> | 2019-10-25 04:15:59 +0000 |
| commit | 4f70c151db6a2f169058a193232263733aa3947e (patch) | |
| tree | a56e1fae61d5b029846374d447a346ea3104419d /src/fmt | |
| parent | 8f30d25168cae6380d9ef50528063716261356c4 (diff) | |
| download | go-4f70c151db6a2f169058a193232263733aa3947e.tar.gz go-4f70c151db6a2f169058a193232263733aa3947e.zip | |
fmt: fix handling of %% verb in Scanf
There were a couple of bugs, including not requiring a percent and
returning the wrong error for a bad format containing %%.
Both are addressed by fixing the first.
Fixes #34180.
Change-Id: If96c0c0258bcb95eec49871437d719cb9d399d9b
Reviewed-on: https://go-review.googlesource.com/c/go/+/202879
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Diffstat (limited to 'src/fmt')
| -rw-r--r-- | src/fmt/scan.go | 13 | ||||
| -rw-r--r-- | src/fmt/scan_test.go | 19 |
2 files changed, 25 insertions, 7 deletions
diff --git a/src/fmt/scan.go b/src/fmt/scan.go index 0dab2c98f7..8cab0180ee 100644 --- a/src/fmt/scan.go +++ b/src/fmt/scan.go @@ -940,6 +940,15 @@ const ( uintptrBits = 32 << (^uintptr(0) >> 63) ) +// scanPercent scans a literal percent character. +func (s *ss) scanPercent() { + s.SkipSpace() + s.notEOF() + if !s.accept("%") { + s.errorString("missing literal %") + } +} + // scanOne scans a single value, deriving the scanner from the type of the argument. func (s *ss) scanOne(verb rune, arg interface{}) { s.buf = s.buf[:0] @@ -1203,6 +1212,10 @@ func (s *ss) doScanf(format string, a []interface{}) (numProcessed int, err erro if c != 'c' { s.SkipSpace() } + if c == '%' { + s.scanPercent() + continue // Do not consume an argument. + } s.argLimit = s.limit if f := s.count + s.maxWid; f < s.argLimit { s.argLimit = f diff --git a/src/fmt/scan_test.go b/src/fmt/scan_test.go index b14a6f5deb..1cc469ce36 100644 --- a/src/fmt/scan_test.go +++ b/src/fmt/scan_test.go @@ -318,13 +318,15 @@ var scanfTests = []ScanfTest{ {"%2s", "sssss", &xVal, Xs("ss")}, // Fixed bugs - {"%d\n", "27\n", &intVal, 27}, // ok - {"%d\n", "28 \n", &intVal, 28}, // was: "unexpected newline" - {"%v", "0", &intVal, 0}, // was: "EOF"; 0 was taken as base prefix and not counted. - {"%v", "0", &uintVal, uint(0)}, // was: "EOF"; 0 was taken as base prefix and not counted. - {"%c", " ", &uintVal, uint(' ')}, // %c must accept a blank. - {"%c", "\t", &uintVal, uint('\t')}, // %c must accept any space. - {"%c", "\n", &uintVal, uint('\n')}, // %c must accept any space. + {"%d\n", "27\n", &intVal, 27}, // ok + {"%d\n", "28 \n", &intVal, 28}, // was: "unexpected newline" + {"%v", "0", &intVal, 0}, // was: "EOF"; 0 was taken as base prefix and not counted. + {"%v", "0", &uintVal, uint(0)}, // was: "EOF"; 0 was taken as base prefix and not counted. + {"%c", " ", &uintVal, uint(' ')}, // %c must accept a blank. + {"%c", "\t", &uintVal, uint('\t')}, // %c must accept any space. + {"%c", "\n", &uintVal, uint('\n')}, // %c must accept any space. + {"%d%%", "23%\n", &uintVal, uint(23)}, // %% matches literal %. + {"%%%d", "%23\n", &uintVal, uint(23)}, // %% matches literal %. // space handling {"%d", "27", &intVal, 27}, @@ -467,6 +469,9 @@ var multiTests = []ScanfMultiTest{ {"X%d", "10X", args(&intVal), nil, "input does not match format"}, {"%d%", "42%", args(&intVal), args(42), "missing verb: % at end of format string"}, {"%d% ", "42%", args(&intVal), args(42), "too few operands for format '% '"}, // Slightly odd error, but correct. + {"%%%d", "xxx 42", args(&intVal), args(42), "missing literal %"}, + {"%%%d", "x42", args(&intVal), args(42), "missing literal %"}, + {"%%%d", "42", args(&intVal), args(42), "missing literal %"}, // Bad UTF-8: should see every byte. {"%c%c%c", "\xc2X\xc2", args(&r1, &r2, &r3), args(utf8.RuneError, 'X', utf8.RuneError), ""}, |