ast: better handling for empty interpolations (#225)

Rather than treat empty interpolations as having no accessors, treat them as having a single accessor that is the empty string. This is still invalid--and we issue an error--but allows us to more faithfully represent the syntactical structure of the document.
pulumi · Jan 31, 2024 · ba2d384 · ba2d384
1 parent 9b88959
commit ba2d384
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Showing 6 changed files with 685 additions and 405 deletions.
diff --git a/ast/property.go b/ast/property.go
@@ -127,6 +127,11 @@ outer:
 		switch access[0] {
 		case '}':
 			// interpolation terminator
+
+			// Handle the case of an empty, terminated access (`${}`)
+			if len(accessors) == 0 {
+				accessors = []PropertyAccessor{&PropertyName{Name: ""}}
+			}
 			return access[1:], &PropertyAccess{Accessors: accessors}, diags
 		case '.':
 			if len(accessors) == 0 {
@@ -216,6 +221,10 @@ outer:
 			}
 		}
 	}
+	// Handle the case of an empty, unterminated access (`${`)
+	if len(accessors) == 0 {
+		accessors = []PropertyAccessor{&PropertyName{Name: ""}}
+	}
 	diags.Extend(syntax.NodeError(node, "unterminated interpolation"))
 	return access, &PropertyAccess{Accessors: accessors}, diags
 }
diff --git a/ast/testdata/parse/invalid-interpolations/env.yaml b/ast/testdata/parse/invalid-interpolations/env.yaml
@@ -1,5 +1,7 @@
 values:
   interpolations:
+    - ${
+    - ${}
     - unterminated ${interpolation
     - missing ${property.} name
     - missing ${property[} subscript

diff --git a/ast/testdata/parse/invalid-interpolations/expected.json b/ast/testdata/parse/invalid-interpolations/expected.json
@@ -10,6 +10,24 @@
                     },
                     "Value": {
                         "Elements": [
+                            {
+                                "Property": {
+                                    "Accessors": [
+                                        {
+                                            "Name": ""
+                                        }
+                                    ]
+                                }
+                            },
+                            {
+                                "Property": {
+                                    "Accessors": [
+                                        {
+                                            "Name": ""
+                                        }
+                                    ]
+                                }
+                            },
                             {
                                 "Parts": [
                                     {
@@ -114,8 +132,8 @@
                 },
                 "End": {
                     "Line": 3,
-                    "Column": 35,
-                    "Byte": 60
+                    "Column": 9,
+                    "Byte": 34
                 }
             },
             "Context": null,
@@ -126,19 +144,19 @@
         },
         {
             "Severity": 1,
-            "Summary": "missing closing bracket in list index",
+            "Summary": "unterminated interpolation",
             "Detail": "",
             "Subject": {
                 "Filename": "invalid-interpolations",
                 "Start": {
                     "Line": 5,
                     "Column": 7,
-                    "Byte": 99
+                    "Byte": 51
                 },
                 "End": {
                     "Line": 5,
-                    "Column": 37,
-                    "Byte": 129
+                    "Column": 35,
+                    "Byte": 79
                 }
             },
             "Context": null,
@@ -147,28 +165,51 @@
             "Extra": null,
             "Path": "values.interpolations[2]"
         },
+        {
+            "Severity": 1,
+            "Summary": "missing closing bracket in list index",
+            "Detail": "",
+            "Subject": {
+                "Filename": "invalid-interpolations",
+                "Start": {
+                    "Line": 7,
+                    "Column": 7,
+                    "Byte": 118
+                },
+                "End": {
+                    "Line": 7,
+                    "Column": 37,
+                    "Byte": 148
+                }
+            },
+            "Context": null,
+            "Expression": null,
+            "EvalContext": null,
+            "Extra": null,
+            "Path": "values.interpolations[4]"
+        },
         {
             "Severity": 1,
             "Summary": "missing closing quote in property name",
             "Detail": "",
             "Subject": {
                 "Filename": "invalid-interpolations",
                 "Start": {
-                    "Line": 6,
+                    "Line": 8,
                     "Column": 7,
-                    "Byte": 136
+                    "Byte": 155
                 },
                 "End": {
-                    "Line": 6,
+                    "Line": 8,
                     "Column": 31,
-                    "Byte": 160
+                    "Byte": 179
                 }
             },
             "Context": null,
             "Expression": null,
             "EvalContext": null,
             "Extra": null,
-            "Path": "values.interpolations[3]"
+            "Path": "values.interpolations[5]"
         },
         {
             "Severity": 1,
@@ -177,21 +218,21 @@
             "Subject": {
                 "Filename": "invalid-interpolations",
                 "Start": {
-                    "Line": 6,
+                    "Line": 8,
                     "Column": 7,
-                    "Byte": 136
+                    "Byte": 155
                 },
                 "End": {
-                    "Line": 6,
+                    "Line": 8,
                     "Column": 31,
-                    "Byte": 160
+                    "Byte": 179
                 }
             },
             "Context": null,
             "Expression": null,
             "EvalContext": null,
             "Extra": null,
-            "Path": "values.interpolations[3]"
+            "Path": "values.interpolations[5]"
         },
         {
             "Severity": 1,
@@ -200,21 +241,21 @@
             "Subject": {
                 "Filename": "invalid-interpolations",
                 "Start": {
-                    "Line": 7,
+                    "Line": 9,
                     "Column": 7,
-                    "Byte": 167
+                    "Byte": 186
                 },
                 "End": {
-                    "Line": 7,
+                    "Line": 9,
                     "Column": 36,
-                    "Byte": 196
+                    "Byte": 215
                 }
             },
             "Context": null,
             "Expression": null,
             "EvalContext": null,
             "Extra": null,
-            "Path": "values.interpolations[4]"
+            "Path": "values.interpolations[6]"
         }
     ]
 }
diff --git a/eval/eval.go b/eval/eval.go
@@ -590,18 +590,6 @@ func (e *evalContext) evaluatePropertyAccess(x *expr, accessors []*propertyAcces
 func (e *evalContext) evaluateExprAccess(x *expr, accessors []*propertyAccessor) *value {
 	receiver := e.root
 
-	// This can happen for invalid property accesses. No need to issue an error here--the parser has already done so.
-	if len(accessors) == 0 {
-		return &value{
-			def: &expr{
-				repr:  &literalExpr{node: x.repr.syntax()},
-				state: exprDone,
-			},
-			schema:  schema.Always().Schema(),
-			unknown: true,
-		}
-	}
-
 	// Check for an imports access.
 	if k, ok := e.objectKey(x.repr.syntax(), accessors[0].accessor, false); ok && k == "imports" {
 		accessors[0].value = e.myImports

diff --git a/eval/testdata/eval/invalid-access-load/env.yaml b/eval/testdata/eval/invalid-access-load/env.yaml
@@ -1,5 +1,6 @@
 values:
   propertyAccessTest:
+    - ${
     - ${open["foo"}
     - ${open["foo]}
     - ${open["foo"]