# multi-swe-bench / sveltejs__svelte14456 - taskset: [multi-swe-bench](https://harnessreport.com/tasks/multi-swe-bench.md) - difficulty: hard - category: software-development - language: - runnable from the site: no - agent timeout: 14400s ## Results by harness _none yet_ ## Instruction ``` <uploaded_files> /workspace/svelte </uploaded_files> I've uploaded a Javascript code repository in the directory /workspace/svelte. Consider the following issue description: <issue_description> # fix: better account for render tags when pruning CSS Fixes #14399 We currently get both false positives (CSS incorrectly assumed to be used) _and_ false negatives (CSS incorrectly assumed to be unused) around render tags at present. We treat render tags as something of a black box, causing false positives which are harmless but undesirable. The false negatives are much worse. This PR works by linking snippets to render tags. In many cases this is straightforward, because they're identified by name — if we have a `{#snippet foo()}` and a `{@render foo()}` in the same component, they are unambiguously linked. Similarly if we have a `{@render children()}` and `children` is a prop, we know that the render tag doesn't correspond to any markup inside the component, and so we don't need to consider it while pruning. Imports are treated the same way as props. Where it gets more complicated is around render tags that can't be trivially statically analysed, and components. In a case like this... ```svelte {#each items as item} {@render item.snippet()} {/each} ``` ...or this... ```svelte <Thing someprop={fn()} /> ``` ...it's impossible to know which snippets will get rendered without more sophisticated static analysis, so in these cases we deopt and assume that the render tag/component could be rendering _any_ locally defined snippets. In practice, this means there will be occasional false positives, but it should eliminate false negatives. ### Before submitting the PR, please make sure you do the following - [x] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs - [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`. - [x] This message body should clearly illustrate what problems it solves. - [x] Ideally, include a test that fails without this PR but passes with it. - [x] If this PR changes code within `packages/svelte/src`, add a changeset (`npx changeset`). ### Tests and linting - [x] Run the tests with `pnpm test` and lint the project with `pnpm lint` ## Repository Information - **Repository**: sveltejs/svelte - **Pull Request**: #14456 - **Base Commit**: `e9ff665bead20d84df4464526a026b2070f3278a` ## Related Issues - https://github.com/sveltejs/svelte/issues/14399 </issue_description> Can you help me implement the necessary changes to the repository so that the requirements specified in the <issue_description> are met? I've already taken care of all changes to any of the test files described in the <issue_description>. This means you DON'T have to modify the testing logic or any of the tests in any way! Also the development Javascript environment is already set up for you (i.e., all dependencies already installed), so you don't need to install other packages. Your task is to make the minimal changes to non-test files in the /workspace/svelte directory to ensure the <issue_description> is satisfied. Follow these phases to resolve the issue: Phase 1. READING: read the problem and reword it in clearer terms 1.1 If there are code or config snippets. Express in words any best practices or conventions in them. 1.2 Highlight message errors, method names, variables, file names, stack traces, and technical details. 1.3 Explain the problem in clear terms. 1.4 Enumerate the steps to reproduce the problem. 1.5 Highlight any best practices to take into account when testing and fixing the issue. Phase 2. RUNNING: install and run the tests on the repository 2.1 Follow the readme. 2.2 Install the environment and anything needed. 2.3 Iterate and figure out how to run the tests. Phase 3. EXPLORATION: find the files that are related to the problem and possible solutions 3.1 Use `grep` to search for relevant methods, classes, keywords and error messages. 3.2 Identify all files related to the problem statement. 3.3 Propose the methods and files to fix the issue and explain why. 3.4 From the possible file locations, select the most likely location to fix the issue. Phase 4. TEST CREATION: before implementing any fix, create a script to reproduce and verify the issue 4.1 Look at existing test files in the repository to understand the test format/structure. 4.2 Create a minimal reproduction script that reproduces the located issue. 4.3 Run the reproduction script with `node <filename.js>` to confirm you are reproducing the issue. 4.4 Adjust the reproduction script as necessary. Phase 5. FIX ANALYSIS: state clearly the problem and how to fix it 5.1 State clearly what the problem is. 5.2 State clearly where the problem is located. 5.3 State clearly how the test reproduces the issue. 5.4 State clearly the best practices to take into account in the fix. 5.5 State clearly how to fix the problem. Phase 6. FIX IMPLEMENTATION: Edit the source code to implement your chosen solution. 6.1 Make minimal, focused changes to fix the issue. Phase 7. VERIFICATION: Test your implementation thoroughly. 7.1 Run your reproduction script to verify the fix works. 7.2 Add edge cases to your test script to ensure comprehensive coverage. 7.3 Run existing tests related to the modified code with `npm test` to ensure you haven't broken anything. Phase 8. FINAL REVIEW: Carefully re-read the problem description and compare your changes with the base commit e9ff665bead20d84df4464526a026b2070f3278a. 8.1 Ensure you've fully addressed all requirements. 8.2 Run any tests in the repository related to: 8.2.1 The issue you are fixing 8.2.2 The files you modified 8.2.3 The functions you changed 8.3 If any tests fail, revise your implementation until all tests pass. Be thorough in your exploration, testing, and reasoning. It's fine if your thinking process is lengthy - quality and completeness are more important than brevity. IMPORTANT CONSTRAINTS: - ONLY modify files within the /workspace/svelte directory - DO NOT navigate outside this directory (no `cd ..` or absolute paths to other locations) - DO NOT create, modify, or delete any files outside the repository - All your changes must be trackable by `git diff` within the repository - If you need to create test files, create them inside the repository directory ``` --- Harness Report runs agent harnesses from their GitHub repos on Harbor tasks and records every model call. Every page is also `.md` and `.json`; index: https://harnessreport.com/llms.txt · MCP: https://harnessreport.com/mcp