internal/filetypes: default strictFeatures to true

In general in JSON Schema we want to ignore keywords which
aren't defined, but it seems better to default to giving an error
when there's a keyword that we know is not implemented,
meaning that the schema cannot be interpreted correctly.

To revert to previous behavior, `jsonschema+strictFeatures=0:`
can be used.

Signed-off-by: Roger Peppe <[email protected]>
Change-Id: I65d24ae8c147d36499b4e02b418bedcc6d1a376b
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1200932
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

Author: rogpeppe

Diff for: cmd/cue/cmd/help.go

@@ -613,14 +613,15 @@ The following tags are only valid in combination with other tags,
 and influence the functioning of the codec. The tag they are
 valid with is mentioned in parentheses at the end.
 
-    strictFeatures	report errors for lossy mappings (jsonschema)
+    strictFeatures	report errors for lossy mappings. Enabled by default (jsonschema)
     strictKeywords	report errors for unknown keywords (jsonschema)
     strict			report errors for either of the above (jsonschema)
 
 The above flags also accept a boolean flag value (e.g. true, 1, false, 0)
-to set them explicitly. For example:
+to set them explicitly. For example, to ignore unimplemented JSON Schema
+features rather than giving an error:
 
-	jsonschema+strictKeywords=0+strictFeatures=1
+	jsonschema+strictFeatures=0
 
 Many commands also support the --out and --outfile/-o flags.
 The --out flag specifies the output type using a qualifier

Diff for: cmd/cue/cmd/testdata/script/def_jsonschema.txtar

@@ -5,7 +5,10 @@ cmp stdout expect-stdout
 exec cue def schema.json -p schema -l '#Person:'
 cmp stdout expect-stdout
 
-exec cue def jsonschema: bad.json
+! exec cue def jsonschema: bad.json
+cmp stderr expect-stderr-strict-features
+
+exec cue def jsonschema+strictFeatures=0: bad.json
 
 ! exec cue def jsonschema: bad.json --strict
 cmp stderr expect-stderr

Diff for: internal/filetypes/filetypes_test.go

@@ -181,7 +181,7 @@ func TestFromFile(t *testing.T) {
 				Form:           build.Schema,
 				BoolTags: map[string]bool{
 					"strict":         false,
-					"strictFeatures": false,
+					"strictFeatures": true,
 					"strictKeywords": false,
 				},
 			},
@@ -419,7 +419,7 @@ func TestParseArgs(t *testing.T) {
 				Interpretation: "jsonschema",
 				BoolTags: map[string]bool{
 					"strict":         false,
-					"strictFeatures": false,
+					"strictFeatures": true,
 					"strictKeywords": false,
 				},
 			},
@@ -439,6 +439,21 @@ func TestParseArgs(t *testing.T) {
 				},
 			},
 		},
+	}, {
+		in: "jsonschema+strictFeatures=0: bar.schema",
+		out: []*build.File{
+			{
+				Filename:       "bar.schema",
+				Encoding:       "json",
+				Interpretation: "jsonschema",
+				Form:           build.Schema,
+				BoolTags: map[string]bool{
+					"strict":         false,
+					"strictFeatures": false,
+					"strictKeywords": false,
+				},
+			},
+		},
 	}, {
 		in: `json: c:\foo.json c:\path\to\file.dat`,
 		out: []*build.File{

Diff for: internal/filetypes/types.cue

@@ -297,7 +297,7 @@ interpretations: jsonschema: {
 	boolTags: {
 		strict:         *false | bool
 		strictKeywords: *strict | bool
-		strictFeatures: *strict | bool
+		strictFeatures: *true | bool
 	}
 }