cmd/cue: fix --ignore errors flag

Fixes #1981
Fixes #1786

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: Ie7461fc6d42bea71db99559c4961271b6a271fd0
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/546243
Unity-Result: CUEcueckoo <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>

cmd/cue/cmd/eval.go

@@ -93,6 +93,7 @@ func runEval(cmd *Command, args []string) error {
 		cue.Definitions(true),
 		cue.Attributes(flagAttributes.Bool(cmd)),
 		cue.Optional(flagAll.Bool(cmd) || flagOptional.Bool(cmd)),
+		cue.ErrorsAsValues(flagIgnore.Bool(cmd)),
 	}
 
 	// Keep for legacy reasons. Note that `cue eval` is to be deprecated by
@@ -143,18 +144,21 @@ func runEval(cmd *Command, args []string) error {
 			b, _ := format.Node(b.expressions[i%len(b.expressions)])
 			id = string(b)
 		}
-		if err := v.Err(); err != nil {
-			errHeader()
-			return v.Validate(syn...)
-		}
 
-		// TODO(#553): this can be removed once v.Syntax() below retains line
-		// information.
-		if (e.IsConcrete() || flagConcrete.Bool(cmd)) && !flagIgnore.Bool(cmd) {
-			if err := v.Validate(cue.Concrete(true)); err != nil {
+		if !flagIgnore.Bool(cmd) {
+			if err := v.Err(); err != nil {
 				errHeader()
-				exitOnErr(cmd, err, false)
-				continue
+				return v.Validate(syn...)
+			}
+
+			// TODO(#553): this can be removed once v.Syntax() below retains line
+			// information.
+			if e.IsConcrete() || flagConcrete.Bool(cmd) {
+				if err := v.Validate(cue.Concrete(true)); err != nil {
+					errHeader()
+					exitOnErr(cmd, err, false)
+					continue
+				}
 			}
 		}
 

cmd/cue/cmd/testdata/script/eval_ignore.txtar

@@ -0,0 +1,20 @@
+exec cue eval -i in.cue
+cmp stdout expect/stdout
+
+# Issue #1981
+# Issue #1786
+-- in.cue --
+a: 4
+a: 5
+
+l: [ 1, 2 ]
+l: [ 1, 3 ]
+
+list: [0, 1, 2]
+val: list[3]
+
+-- expect/stdout --
+a: _|_ // a: conflicting values 5 and 4
+l: [1, _|_]
+list: [0, 1, 2]
+val: _|_ // val: index out of range [3] with length 3

cue/types.go

@@ -2137,6 +2137,14 @@ func ResolveReferences(resolve bool) Option {
 	}
 }
 
+// ErrorsAsValues treats errors as a regular value, including them at the
+// location in the tree where they occur, instead of interpreting them as a
+// configuration-wide failure that is returned instead of root value.
+// Used by Syntax.
+func ErrorsAsValues(show bool) Option {
+	return func(p *options) { p.showErrors = show }
+}
+
 // Raw tells Syntax to generate the value as is without any simplifications.
 func Raw() Option {
 	return func(p *options) { p.raw = true }