Fix several bugs with native GDB DAP#12
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Two bugs caused expression evaluation to fail with GDB's native DAP: 1. Default evaluate context was "repl", which GDB interprets as a GDB command rather than a language expression. Changed default to "watch" per DAP spec semantics. 2. go-dap's EvaluateArguments uses omitempty on FrameId, which drops frameId=0 from the JSON. GDB uses 0-based frame IDs, so this caused evaluation in global scope where local variables aren't visible. Fixed by building evaluate arguments as raw JSON. Also fixed FrameID parameter to use *FlexInt (pointer) so we can distinguish "user sent frameId=0" from "frameId not provided", and changed lastFrameID sentinel from 0 to -1 since 0 is a valid GDB frame ID. Adds regression tests for bare expressions, pointer dereference, address-of, casts, and register access with GDB backend. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Guide AI models to use valid language expressions (not GDB commands like /x) in the default watch context, and document how to use repl context for GDB-specific commands. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
GDB's native DAP distinguishes between stopOnEntry (starti, first instruction in dynamic linker) and stopAtBeginningOfMainSubprogram (start, main function). The latter is almost always the desired behavior, matching what users expect from "stop on entry". Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
MCP clients can make concurrent tool calls, but the DAP connection has a single reader. Without serialization, concurrent calls race on the reader and receive each other's responses (e.g., info(threads) gets a ScopesResponse from a concurrent context call). Add a sync.Mutex to debuggerSession that each tool handler acquires before sending DAP requests, preventing interleaved reads. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace single-reader architecture docs with serialized mutex docs now that concurrent tool calls are properly serialized. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Fix an issue around serialization of certain requests where the frameID gets lost due to the go-dap extension thinking the
inthas its zero value and omitting it.Rely more heavily on request / response sequencing to ensure we are waiting for and receiving the correct response.