fix: @partial-block usable in #if and as block partial (issue #519)#624
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Two sub-bugs fixed:
- BindingContext.TryGetContextVariable now returns the PartialBlockTemplate
delegate when the segment is 'partial-block', making {{#if @partial-block}}
truthy whenever a block partial is in scope.
- PartialBlockAccumulatorContext.GetAccumulatedBlock now handles an empty
body ({{#> @partial-block }}{{/@partial-block}}) without crashing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
|
| handlebars.RegisterTemplate("myPartial", | ||
| @"Conditional:{{#if @partial-block}} {{> @partial-block}}{{/if}} | ||
| Plain: {{> @partial-block}} | ||
| Block:{{#> @partial-block }}{{/@partial-block}}"); |
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Using
Block:{{#> @partial-block }}any fallback{{/@partial-block}}
should still let the test pass, but doesn't, right? I am a bit stuck in figuring out the right solution for this, so I can continue with #606
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Fixes #519
Summary
{{#if @partial-block}}now correctly evaluates as truthy when the partial is invoked as a block partial (i.e., when a@partial-blocktemplate is in scope).{{#> @partial-block }}{{/@partial-block}}no longer crashes withInvalidOperationException: Sequence contains no elementswhen the body between the tags is empty.Root causes
Bug 1 —
{{#if @partial-block}}always falsy:@partial-blockis aPathType.Variable, so its value is resolved viaBindingContext.TryGetContextVariable. ThePartialBlockTemplateis stored directly onBindingContextand was never exposed through the context data dictionary, so it always returnedUndefinedBindingResult(falsy). Fixed by adding an explicit check inTryGetContextVariablefor the segment namepartial-blockthat returns thePartialBlockTemplatedelegate when set.Bug 2 —
{{#> @partial-block }}{{/@partial-block}}crashes:PartialBlockAccumulatorContext.GetAccumulatedBlock()called_body.First()unconditionally, which throws when the body is empty. Fixed by handling the empty-body case (passingnullas the fallback, which is already the documented no-fallback sentinel inPartialExpression).Test plan
Issue519_PartialBlockUsableAsBlockAndInIfadded toIssueTests.cs— exercises{{#if @partial-block}},{{> @partial-block}}, and{{#> @partial-block}}{{/@partial-block}}in the same partial.🤖 Generated with Claude Code