Fix invalid subtyping relationship in xml #42221

poorna2152 · 2024-02-26T05:15:10Z

Purpose

Approach

Update isAssignable to not to allow assigning of value with static typexml to value with static type xml:Comment|xml:Element|xml:ProcessingInstruction|xml:Text. But this assignment is allowed in the type binding pattern in theforeach loops. Thus in order to handle this case new function is introduced constituentTypesAssignable.

Samples

Provide high-level details about the samples related to this feature.

Remarks

List any other known issues, related PRs, TODO items, or any other notes related to the PR.

Check List

codecov · 2024-02-27T12:19:28Z

Codecov Report

Attention: Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.

Project coverage is 77.53%. Comparing base (b2251b8) to head (3db666f).
Report is 23 commits behind head on master.

Files with missing lines	Patch %	Lines
...llerinalang/compiler/semantics/analyzer/Types.java	88.88%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master   #42221   +/-   ##
=========================================
  Coverage     77.53%   77.53%           
- Complexity    58717    58725    +8     
=========================================
  Files          3447     3447           
  Lines        219689   219716   +27     
  Branches      28937    28941    +4     
=========================================
+ Hits         170335   170363   +28     
+ Misses        39934    39933    -1     
  Partials       9420     9420

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

MaryamZi · 2024-02-29T04:59:26Z

...-lang/src/main/java/org/wso2/ballerinalang/compiler/semantics/analyzer/SemanticAnalyzer.java

-        if (types.isAssignable(varType, typeNodeType)) {
+        if (types.constituentTypesAssignable(varType, typeNodeType)) {


Why are we changing these? isAssignable should produce correct results.

This is a special case. With the modification to isAssignable function in this PR, variable with static type of xml is not assignable to xml<xml:Element>|xml<xml:Comment>|xml<xml:ProcessingInstruction>|xml:Text or xml:Element|xml:Comment|xml:ProcessingInstruction|xml:Text(Which is the correct behaviour and which is expected).

The function given here is used to validate the types in a foreach loop. In a foreach loop context, variable with static type xml is assignable to loop variable of type xml<xml:Element>|xml<xml:Comment>|xml<xml:ProcessingInstruction>|xml:Text. Thus here it is not possible to use isAssignable

Example code,

function foo() { xml x = xml `<a></a>text<?data?>`; foreach xml:Element|xml:Comment|xml:ProcessingInstruction|xml:Text item in x { } }

The function given here is used to validate the types in a foreach loop. In a foreach loop context, variable with static type xml is assignable to loop variable of type xml<xml:Element>|xml<xml:Comment>|xml<xml:ProcessingInstruction>|xml:Text. Thus here it is not possible to use isAssignable

This definition isn't entirely correct, is it? In the loop/foreach case we should be checking the sequence member type (xml:Element|xml:Comment|xml:ProcessingInstruction|xml:Text) against the foreach variable type, not xml.

Right, yes. But we cannot isAssignable for this check right, since for variable with static type xml it can't be assigned to xml:Element|xml:Comment|xml:ProcessingInstruction|xml:Text.

In the case of type parameter the assignability is checked using the isAssignable(sourceParam, targetParam)
In the case of xml we cannot use this check.
Consider the following code

xml x = xml `<a>a</a>`; x.forEach(function (xml entry) { });

Here the targetType is xml:Element|xml:Comment|xml:ProcessingInstruction|xml:Text and the source type is xml. Since an xml value cannot be assigned to ``xml:Element|xml:Comment|xml:ProcessingInstruction|xml:Text` the check for xml is made special case for type params in this commit

github-actions · 2024-03-16T19:33:01Z