Fix null pointer dereference in LSP hover handler for undocumented IdentifierPath declarations

[Varunthaplyall]

Description

Fixes #16766

The IdentifierPath branch in DocumentHoverHandler calls structurallyDocumented->documentation()->text() without first checking whether documentation() returns nullptr. When a declaration referenced through an IdentifierPath (e.g., inheritance specifier, modifier invocation, override specifier, using directive) has no NatSpec documentation, this causes a segfault (exit code 139).

Changes

• libsolidity/lsp/DocumentHoverHandler.cpp: Added a null check on documentation() before accessing text(), matching the pattern already used for the sourceNode branch on line 108 of the same file.

Root cause

The StructurallyDocumented::documentation() method explicitly documents that it "Can contain a nullptr in which case indicates absence of documentation" (see libsolidity/ast/AST.h:497). The sibling branch (lines 108-109) correctly guards against this, but the IdentifierPath branch did not.

Testing

The existing LSP hover tests at test/libsolidity/lsp/hover/hover.sol continue to pass. No new tests needed as the fix simply applies the same null-check pattern already present in the same function.

Risk

Minimal. This is a one-line addition that mirrors existing code in the same function.

[clonker]

LSP is unmaintained, deprecated, and will be removed soon. Fixing anything here doesn't get us anywhere. In that sense, deleting LSP from the codebase is the proper fix for the issue you linked. Still, thank you for the interest and contribution!