mcpp-language-server 0.0.12: the maintained mcppls-clangd engine, mcpp formatting, crash recovery, linux-arm64 again

.agents/docs/2026-10-07-darwin-pipe-write.md

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+# Darwin child-pipe writes
+
+Register: [UP-O1](https://github.com/Sunrisepeak/mcpp-language-server/issues/24#issuecomment-6028338032). Compensation: WA-PLATFORM-001 in
+modules/platform/src/process.cpp. This is a platform runtime issue and belongs
+outside the clangd workaround registry.
+
+The Intel runner executes the actual cross-built dev/release binaries. Both
+failed by signal 13 in the existing blocked-peer shutdown test (CI run
+37552260398, jobs 112572688643/112572688644). openkal-macos 0.12.0's env.cpp
+explicitly records that its pipe writes can trigger SIGPIPE; its C-library
+layer does not install a kernel signal disposition.
+
+Each parent-owned child-input write descriptor now receives F_SETNOSIGPIPE
+before spawn. Darwin's existing native syscall convention is used because the
+program supplies its own C ABI. Failure closes both input ends and the work
+handle, and rejects spawn. The change is local to that descriptor. Constants
+and semantics: [Apple XNU fcntl.h](https://github.com/apple-oss-distributions/xnu/blob/main/bsd/sys/fcntl.h).
+
+Evidence: Linux process tests pass, 2 binaries; the main test has 23 cases and
+86 assertions. Intel and arm64 process tests cross-compile (2 binaries each). Fixed-byte
+native CI remains pending. The new regression explicitly
+waits for peer exit, writes to its still-open parent end and requires a returned
+process-write error. Existing blocked-writer shutdown remains the lifecycle
+canary. No native success is inferred from cross-linking.
+
+Remove WA-PLATFORM-001 only when selected openkal-macos reliably reports closed
+pipe writes on both macOS architectures with default parent SIGPIPE handling.
+Other arbitrary openkal streams do not gain a blanket protection from this fix.
+
+Native follow-up: Intel dev CI run 37553665184 / job 112577351043 at
+1fa6975 passes the blocked-peer and closed-peer write canaries and both process
+binaries (main: 23 cases, 80 assertions). The job fails later in a separate
+pack platform fixture, which has now been corrected. Native release proof
+is still pending because that fixture ran before its process tests.

.agents/docs/2026-10-07-mcpp-format-review/README.md

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+# mcpp fallback formatting review
+
+The upstream configuration is a byte-preserving snapshot from mcpp commit
+74bcb859e60afc71ad759540d2de5344dda400e9. Its SHA is recorded in snapshot.json.
+The snapshot and named preset parse with clang-format 23 and both produce
+expected.cppm. The engine golden/override and raw LSP fallback tests pass.
+Product editor acceptance and final four-platform bytes remain pending.
+
+The maintained engine will register the named `mcpp` C++ preset from this
+snapshot. Existing `.clang-format` discovery remains authoritative. The product
+may select this fallback only when verified engine metadata declares
+`format-style-mcpp`, and only by default for an mcpp project. Explicit user
+fallback settings take priority. External or legacy engines receive no unknown
+preset, and no configuration file is written into a user's project.
+
+The fixture covers global module fragments, import, constrained templates,
+namespaces, lambdas, constructor initializers and long expressions. Final golden
+output must be generated and checked with the same clang 23 formatter as the
+maintained preset. A named preset and this snapshot must yield identical output;
+project overrides and explicit user fallback are separate acceptance cases.

.agents/docs/2026-10-07-mcpp-format-review/expected.cppm

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+module;
+#include <stddef.h>
+export module format.demo;
+import std;
+export namespace demo {
+template <class T>
+requires requires(T x) { x + x; }
+T sum(T first, T second) {
+    auto combine = [&](T left, T right) { return left + right; };
+    return combine(first, second);
+}
+class Buffer {
+public:
+    Buffer(int capacity, int limit) : capacity_(capacity), limit_(limit) {}
+    int scaled() const {
+        return capacity_ * limit_ + capacity_ * limit_ + capacity_ * limit_ + capacity_ * limit_ +
+               capacity_ * limit_;
+    }
+private:
+    int capacity_;
+    int limit_;
+};
+}  // namespace demo

.agents/docs/2026-10-07-mcpp-format-review/input.cppm

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+module;
+#include <stddef.h>
+export module format.demo;
+import std;
+export namespace demo {template<class T> requires requires(T x){x+x;} T sum(T first,T second){auto combine=[&](T left,T right){return left+right;};return combine(first,second);}
+class Buffer {public:Buffer(int capacity,int limit):capacity_(capacity),limit_(limit){} int scaled() const{return capacity_*limit_+capacity_*limit_+capacity_*limit_+capacity_*limit_+capacity_*limit_;}private:int capacity_;int limit_;};}

.agents/docs/2026-10-07-mcpp-format-review/snapshot.json

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+{
+  "source-repository": "https://github.com/mcpp-community/mcpp",
+  "source-commit": "74bcb859e60afc71ad759540d2de5344dda400e9",
+  "source-path": ".clang-format",
+  "sha256": "e03547822b284dd66a266c18586575c71581b8a32bef02325851763b44dcb2c4",
+  "clang23-validation": "preset and snapshot produce identical golden output; two engine lit tests pass"
+}

.agents/docs/2026-10-07-mcpp-format-review/upstream.clang-format

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+# -----------------------------------------------------------------------------
+# mcpp-community C++ Style Configuration
+#
+# This configuration follows the style specification defined in:
+# https://github.com/mcpp-community/mcpp-style-ref
+#
+# Maintained by: mcpp-community
+# -----------------------------------------------------------------------------
+
+Language: Cpp # Apply configuration to C++
+
+# -----------------------------------------------------------------------------
+# Language Standard
+# -----------------------------------------------------------------------------
+Standard: Latest # Always use the latest supported C++ standard
+
+# -----------------------------------------------------------------------------
+# Indentation
+# -----------------------------------------------------------------------------
+IndentWidth: 4 # Use 4 spaces for indentation
+TabWidth: 4 # Visual width of tab
+UseTab: Never # Never use tabs
+
+# -----------------------------------------------------------------------------
+# Line Width
+# -----------------------------------------------------------------------------
+ColumnLimit: 100 # Maximum line width
+
+# -----------------------------------------------------------------------------
+# Spaces
+# -----------------------------------------------------------------------------
+SpaceBeforeParens: ControlStatements # Space before parentheses for control statements (if/for/while); function calls remain tight
+SpacesInContainerLiterals: true # Enforce spaces in container literals
+SpaceBeforeAssignmentOperators: true # Add space before assignment operators
+SpacesInParentheses: false # No extra spaces inside parentheses
+PointerAlignment: Left # Pointer/reference attaches to type
+QualifierAlignment: Left # Place qualifiers like const to the left
+
+# -----------------------------------------------------------------------------
+# Braces
+# -----------------------------------------------------------------------------
+BreakBeforeBraces: Attach # Opening brace stays on same line
+AllowShortFunctionsOnASingleLine: Empty # Allow empty functions like `void f() {}`
+AllowShortIfStatementsOnASingleLine: Never # Disallow single-line if statements
+AllowShortBlocksOnASingleLine: Empty # Allow empty blocks on one line
+AllowShortLoopsOnASingleLine: false # Disallow one-line loops
+
+# -----------------------------------------------------------------------------
+# Constructor Initializer List
+# -----------------------------------------------------------------------------
+BreakConstructorInitializers: BeforeColon # Keep initializer list compact when short
+ConstructorInitializerAllOnOneLineOrOnePerLine: true # Allow compact initializer lists
+BreakConstructorInitializersBeforeComma: false # Do not break before commas
+
+# -----------------------------------------------------------------------------
+# Access Modifiers
+# -----------------------------------------------------------------------------
+AccessModifierOffset: -4 # Align access modifiers with class indentation
+EmptyLineBeforeAccessModifier: Never # Do not insert empty line before access specifiers
+EmptyLineAfterAccessModifier: Never # Do not insert empty line after access specifiers
+
+# -----------------------------------------------------------------------------
+# Namespace Formatting
+# -----------------------------------------------------------------------------
+NamespaceIndentation: None # Do not indent contents inside namespace
+FixNamespaceComments: true # Enforce closing namespace comments
+CompactNamespaces: true # Prefer namespace a::b instead of nested namespaces
+
+# -----------------------------------------------------------------------------
+# Switch / Case Formatting
+# -----------------------------------------------------------------------------
+IndentCaseLabels: true # Indent case/default labels
+IndentCaseBlocks: true # Indent statements inside case blocks
+
+# -----------------------------------------------------------------------------
+# Includes
+# -----------------------------------------------------------------------------
+SortIncludes: true # Automatically sort includes
+IncludeBlocks: Regroup # Regroup include blocks
+IncludeCategories:
+  - Regex: "^<.*>" # Standard / third-party headers
+    Priority: 1
+  - Regex: '^".*"' # Project headers
+    Priority: 2
+
+# -----------------------------------------------------------------------------
+# Comment Alignment
+# -----------------------------------------------------------------------------
+AlignTrailingComments: true # Align trailing comments
+SpacesBeforeTrailingComments: 2 # Two spaces before trailing comments
+
+# -----------------------------------------------------------------------------
+# Parameter Formatting
+# -----------------------------------------------------------------------------
+BinPackParameters: true # Allow parameters on same line
+BinPackArguments: true # Allow arguments on same line
+
+# -----------------------------------------------------------------------------
+# Template Formatting
+# -----------------------------------------------------------------------------
+AlwaysBreakTemplateDeclarations: Yes # Always place template declarations on their own line
+
+# -----------------------------------------------------------------------------
+# Operator Line Breaking
+# -----------------------------------------------------------------------------
+BreakBeforeBinaryOperators: None # Break after operators
+
+# -----------------------------------------------------------------------------
+# Method Chain Formatting
+# -----------------------------------------------------------------------------
+PenaltyBreakBeforeFirstCallParameter: 10000 # Avoid breaking chained calls unless necessary
+
+# -----------------------------------------------------------------------------
+# Lambda Formatting
+# -----------------------------------------------------------------------------
+AllowShortLambdasOnASingleLine: All # Allow short lambdas on one line
+
+# -----------------------------------------------------------------------------
+# Using Declarations
+# -----------------------------------------------------------------------------
+SortUsingDeclarations: true # Automatically sort using declarations
+
+# -----------------------------------------------------------------------------
+# Return Type Formatting
+# -----------------------------------------------------------------------------
+AlwaysBreakAfterReturnType: None # Break return type only when exceeding ColumnLimit
+
+# -----------------------------------------------------------------------------
+# Concepts / Requires
+# -----------------------------------------------------------------------------
+RequiresClausePosition: OwnLine # Force requires clause to a new line
+IndentRequiresClause: false # Do not indent requires clause