encoding/jsonschema: implement regex format

As the TODO says, this is a bit stricter than the specification,
but it will probably be OK for now.

For #3479.

Signed-off-by: Roger Peppe <rogpeppe@gmail.com>
Change-Id: Icbc9bf6a98058d5f6ca9c0fe87f5e29e4685255b
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1202108
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>

encoding/jsonschema/constraints_format.go

@@ -48,7 +48,7 @@ var formatFuncs = sync.OnceValue(func() map[string]formatFuncInfo {
 		"iri-reference":         {vfrom(VersionDraft7), formatURIReference},
 		"json-pointer":          {vfrom(VersionDraft6), formatTODO},
 		"password":              {openAPI, formatTODO},
-		"regex":                 {vfrom(VersionDraft7), formatTODO},
+		"regex":                 {vfrom(VersionDraft7), formatRegex},
 		"relative-json-pointer": {vfrom(VersionDraft7), formatTODO},
 		"time":                  {vfrom(VersionDraft7), formatTODO},
 		// TODO we should probably disallow non-ASCII URIs (IRIs) but
@@ -100,4 +100,10 @@ func formatDateTime(n cue.Value, s *state) {
 	s.add(n, stringType, ast.NewSel(s.addImport(n, "time"), "Time"))
 }
 
+func formatRegex(n cue.Value, s *state) {
+	// TODO this is a bit stricter than the spec, because the spec
+	// allows Perl idioms such as back-references.
+	s.add(n, stringType, ast.NewSel(s.addImport(n, "regexp"), "Valid"))
+}
+
 func formatTODO(n cue.Value, s *state) {}

encoding/jsonschema/external_teststats.txt

@@ -1,22 +1,22 @@
 # Generated by teststats. DO NOT EDIT
 v2:
 	schema extract (pass / total): 993 / 1363 = 72.9%
-	tests (pass / total): 3513 / 4803 = 73.1%
-	tests on extracted schemas (pass / total): 3513 / 3801 = 92.4%
+	tests (pass / total): 3512 / 4803 = 73.1%
+	tests on extracted schemas (pass / total): 3512 / 3801 = 92.4%
 
 v3:
 	schema extract (pass / total): 981 / 1363 = 72.0%
-	tests (pass / total): 3474 / 4803 = 72.3%
-	tests on extracted schemas (pass / total): 3474 / 3757 = 92.5%
+	tests (pass / total): 3473 / 4803 = 72.3%
+	tests on extracted schemas (pass / total): 3473 / 3757 = 92.4%
 
 Optional tests
 
 v2:
 	schema extract (pass / total): 230 / 274 = 83.9%
-	tests (pass / total): 1505 / 2372 = 63.4%
-	tests on extracted schemas (pass / total): 1505 / 2258 = 66.7%
+	tests (pass / total): 1508 / 2372 = 63.6%
+	tests on extracted schemas (pass / total): 1508 / 2258 = 66.8%
 
 v3:
 	schema extract (pass / total): 230 / 274 = 83.9%
-	tests (pass / total): 1495 / 2372 = 63.0%
-	tests on extracted schemas (pass / total): 1495 / 2258 = 66.2%
+	tests (pass / total): 1498 / 2372 = 63.2%
+	tests on extracted schemas (pass / total): 1498 / 2258 = 66.3%

encoding/jsonschema/testdata/external/tests/draft2019-09/optional/format/regex.json

@@ -44,11 +44,7 @@
 			{
 				"description": "a regular expression with unclosed parens is invalid",
 				"data": "^(abc]",
-				"valid": false,
-				"skip": {
-					"v2": "unexpected success",
-					"v3": "unexpected success"
-				}
+				"valid": false
 			}
 		]
 	}

encoding/jsonschema/testdata/external/tests/draft2020-12/format.json

@@ -127,7 +127,11 @@
 			{
 				"description": "invalid regex string is only an annotation by default",
 				"data": "^(abc]",
-				"valid": true
+				"valid": true,
+				"skip": {
+					"v2": "6 errors in empty disjunction:\nconflicting values \"^(abc]\" and [...] (mismatched types string and list):\n    generated.cue:4:1\n    generated.cue:4:39\n    instance.json:1:1\nconflicting values \"^(abc]\" and bool (mismatched types string and bool):\n    generated.cue:4:1\n    generated.cue:4:8\n    instance.json:1:1\nconflicting values \"^(abc]\" and null (mismatched types string and null):\n    generated.cue:4:1\n    instance.json:1:1\nconflicting values \"^(abc]\" and number (mismatched types string and number):\n    generated.cue:4:1\n    generated.cue:4:15\n    instance.json:1:1\nconflicting values \"^(abc]\" and {...} (mismatched types string and struct):\n    generated.cue:4:1\n    generated.cue:4:47\n    instance.json:1:1\ninvalid value \"^(abc]\" (does not satisfy regexp.Valid): error in call to regexp.Valid: error parsing regexp: missing closing ): `^(abc]`:\n    generated.cue:1:1\n    instance.json:1:1\n",
+					"v3": "conflicting values \"^(abc]\" and [...] (mismatched types string and list):\n    generated.cue:4:39\n    instance.json:1:1\nconflicting values \"^(abc]\" and bool (mismatched types string and bool):\n    generated.cue:4:8\n    instance.json:1:1\nconflicting values \"^(abc]\" and null (mismatched types string and null):\n    generated.cue:4:1\n    instance.json:1:1\nconflicting values \"^(abc]\" and number (mismatched types string and number):\n    generated.cue:4:15\n    instance.json:1:1\nconflicting values \"^(abc]\" and {...} (mismatched types string and struct):\n    generated.cue:4:47\n    instance.json:1:1\ninvalid value \"^(abc]\" (does not satisfy regexp.Valid): error in call to regexp.Valid: error parsing regexp: missing closing ): `^(abc]`:\n    generated.cue:1:1\n    instance.json:1:1\n"
+				}
 			}
 		]
 	},

encoding/jsonschema/testdata/external/tests/draft2020-12/optional/format/regex.json

@@ -44,11 +44,7 @@
 			{
 				"description": "a regular expression with unclosed parens is invalid",
 				"data": "^(abc]",
-				"valid": false,
-				"skip": {
-					"v2": "unexpected success",
-					"v3": "unexpected success"
-				}
+				"valid": false
 			}
 		]
 	}

encoding/jsonschema/testdata/external/tests/draft7/optional/format/regex.json

@@ -43,11 +43,7 @@
 			{
 				"description": "a regular expression with unclosed parens is invalid",
 				"data": "^(abc]",
-				"valid": false,
-				"skip": {
-					"v2": "unexpected success",
-					"v3": "unexpected success"
-				}
+				"valid": false
 			}
 		]
 	}