A virtual jailed shell environment for Go apps backed by an io/fs#FS.
test(printf): cover %b, %c, format reuse, width/precision, --
Documents the bash-influenced -v VAR flag as a kefka
extension (GNU printf has no -v) and adds the previously
missing tests for:
- %b escape interpretation (\\n, \\c, \\t, \\\\, \\0nnn)
- format reuse with arg list longer than the format
- width/precision (%5.3s, %-10d, %05d)
- -- separator before a literal -v format
Refs: docs/posix2018/CONFORMANCE.md
Assisted-by: Claude Opus 4.7 via Claude Code
Signed-off-by: Xe Iaso <me@xeiaso.net>
+51
+6
command/internal/printf/printf.go
+6
command/internal/printf/printf.go
···
44
44
return interp.ExitStatus(2)
45
45
}
46
46
47
+
// -v VAR is a kefka extension influenced by the bash builtin: it stores
48
+
// the formatted output in VAR instead of writing to stdout. GNU coreutils
49
+
// printf does not support -v, but kefka's shell integration depends on
50
+
// it, so it is preserved here. Passing "--" before the format disables
51
+
// option parsing, matching POSIX usage so a literal "-v" can still be
52
+
// printed via `printf -- '%s' '-v'`.
47
53
var targetVar string
48
54
hasTargetVar := false
49
55
argIdx := 0
+45
command/internal/printf/printf_test.go
+45
command/internal/printf/printf_test.go
···
242
242
wantStdout: "hi",
243
243
},
244
244
{
245
+
name: "%b interprets backslash newline",
246
+
args: []string{"%b", "\\n"},
247
+
wantStdout: "\n",
248
+
},
249
+
{
250
+
name: "%b terminates at \\c",
251
+
args: []string{"%b", "a\\cb"},
252
+
wantStdout: "a",
253
+
},
254
+
{
255
+
name: "%b interprets backslash tab",
256
+
args: []string{"%b", "a\\tb"},
257
+
wantStdout: "a\tb",
258
+
},
259
+
{
260
+
name: "%b interprets double backslash",
261
+
args: []string{"%b", "a\\\\b"},
262
+
wantStdout: "a\\b",
263
+
},
264
+
{
265
+
name: "%b interprets octal escape",
266
+
args: []string{"%b", "\\0101"},
267
+
wantStdout: "A",
268
+
},
269
+
{
270
+
name: "format reuse %d %d with extra args",
271
+
args: []string{"%d %d\\n", "1", "2", "3", "4"},
272
+
wantStdout: "1 2\n3 4\n",
273
+
},
274
+
{
275
+
name: "width and precision combined %5.3s",
276
+
args: []string{"%5.3s", "hello"},
277
+
wantStdout: " hel",
278
+
},
279
+
{
280
+
name: "left-justified width %-10d",
281
+
args: []string{"|%-10d|", "42"},
282
+
wantStdout: "|42 |",
283
+
},
284
+
{
285
+
name: "literal -v after -- separator",
286
+
args: []string{"--", "%s", "-v"},
287
+
wantStdout: "-v",
288
+
},
289
+
{
245
290
name: "hex input parsed",
246
291
args: []string{"%d", "0x1f"},
247
292
wantStdout: "31",