redis-cli: Better --json Unicode support and --quoted-json (#10286)

Normally, `redis-cli` escapes non-printable data received from Redis, using a custom scheme (which is also used to handle quoted input). When using `--json` this is not desired as it is not compatible with RFC 7159, which specifies JSON strings are assumed to be Unicode and how they should be escaped.

This commit changes `--json` to follow RFC 7159, which means that properly encoded Unicode strings in Redis will result with a valid Unicode JSON.

However, this introduces a new problem with `--json` and data that is not valid Unicode (e.g., random binary data, text that follows other encoding, etc.). To address this, we add `--quoted-json` which produces JSON strings that follow the original redis-cli quoting scheme.

For example, a value that consists of only null (0x00) bytes will show up as:
* `"\u0000\u0000\u0000"` when using `--json`
* `"\\x00\\x00\\x00"` when using `--quoted-json`

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/integration/redis-cli.tcl b/tests/integration/redis-cli.tcl
index 88b189ac0..c26722961 100644
--- a/tests/integration/redis-cli.tcl
+++ b/tests/integration/redis-cli.tcl
@@ -228,6 +228,30 @@ start_server {tags {"cli"}} {
         file delete $tmpfile
     }
 
+    test_tty_cli "Escape character in JSON mode" {
+        # reverse solidus
+        r hset solidus \/ \/
+        assert_equal \/ \/ [run_cli hgetall solidus]
+        set escaped_reverse_solidus \"\\"
+        assert_equal $escaped_reverse_solidus $escaped_reverse_solidus [run_cli --json hgetall \/]
+        # non printable (0xF0 in ISO-8859-1, not UTF-8(0xC3 0xB0))
+        set eth "\xf0\x65"
+        r hset eth test $eth
+        assert_equal \"\\xf0e\" [run_cli hget eth test]
+        assert_equal \"\xf0e\" [run_cli --json hget eth test]
+        assert_equal \"\\\\xf0e\" [run_cli --quoted-json hget eth test]
+        # control characters
+        r hset control test "Hello\x00\x01\x02\x03World"
+        assert_equal \"Hello\\u0000\\u0001\\u0002\\u0003World" [run_cli --json hget control test]
+        # non-string keys
+        r hset numkey 1 One
+        assert_equal \{\"1\":\"One\"\} [run_cli --json hgetall numkey]
+        # non-string, non-printable keys
+        r hset npkey "K\x00\x01ey" "V\x00\x01alue"
+        assert_equal \{\"K\\u0000\\u0001ey\":\"V\\u0000\\u0001alue\"\} [run_cli --json hgetall npkey]
+        assert_equal \{\"K\\\\x00\\\\x01ey\":\"V\\\\x00\\\\x01alue\"\} [run_cli --quoted-json hgetall npkey]
+    }
+
     test_nontty_cli "Status reply" {
         assert_equal "OK" [run_cli set key bar]
         assert_equal "bar" [r get key]