Specify UTF-8 charset explicitly in STDIO transport InputStreamReader#826
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xxxxxxjun wants to merge 6 commits intomodelcontextprotocol:mainmodelcontextprotocol/java-sdk:mainfrom
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Specify UTF-8 charset explicitly in STDIO transport InputStreamReader#826xxxxxxjun wants to merge 6 commits intomodelcontextprotocol:mainmodelcontextprotocol/java-sdk:mainfrom xxxxxxjun:fix/stdio-encoding-inconsistencyxxxxxxjun/java-sdk:fix/stdio-encoding-inconsistencyCopy head branch name to clipboard
xxxxxxjun wants to merge 6 commits intomodelcontextprotocol:mainmodelcontextprotocol/java-sdk:mainfrom
xxxxxxjun:fix/stdio-encoding-inconsistencyxxxxxxjun/java-sdk:fix/stdio-encoding-inconsistencyCopy head branch name to clipboard
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As explained in #295 (comment), a valid contribution would include a test verifying that the solution is correct. Thank you. |
Verifies that multi-byte UTF-8 characters (Korean, emoji, accented Latin, Japanese) are correctly preserved through the STDIO inbound processing pipeline.
Use natural script names (한글, 漢字) and a common accented word (café) for UTF-8 encoding test data.
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@chemicL Thank you for the feedback. I've added a test that verifies multi-byte UTF-8 characters are correctly preserved through the STDIO inbound processing pipeline. |
chemicL
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Feb 21, 2026
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| @Test | ||
| @SuppressWarnings("unchecked") | ||
| void shouldHandleUtf8EncodedMessages() throws Exception { |
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the test passes without the changes.
The test passes regardless of whether UTF-8 is explicitly specified, because the test environment default charset is already UTF-8.
Spawns a child JVM with -Dfile.encoding=ISO-8859-1 to simulate a non-UTF-8 default charset environment. The test sends a JSON-RPC message containing multi-byte characters (Korean, Chinese, accented Latin, emoji) through StdioServerTransportProvider and verifies they are preserved. This test fails without the explicit UTF-8 charset fix and passes with it.
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Add explicit UTF-8 charset to InputStreamReader in STDIO transports.
Resolves #295
Motivation and Context
Input streams in StdioClientTransport and StdioServerTransportProvider were missing explicit UTF-8 charset, while output streams already specify it.
How Has This Been Tested?
Existing STDIO transport tests pass locally.
Breaking Changes
No
Types of changes
Checklist
Additional context
AI tools were used for drafting the PR description.