Dereference of opaque sqlite3_context type.

[levydsa]

sqlite3_context is a opaque type when used out of vdbe.c and should not be dereferenced, since it's definition is incomplete at comptime.

libsql/libsql-sqlite3/src/alter.c

Lines 1868 to 1870 in be6a38f

	// TODO: figure out more illegal combinations to validate
	rc = renameParseSql(&sPostAlterParse, zDb, db, (const char *)sqlite3_value_text((sqlite3_value *)context->pOut), bTemp);
	Table *pNewTab = sPostAlterParse.pNewTable;

This goes under the radar because of the "amalgamation" aproach to build the source. (Yet another drawback #1028 (comment)). The solution is to #include "vdbeInt.h", but this is very smelly. If the type should be known by the whole source, better add it to sqlite3Int.h.

The func.c includes vdbeInt.h already.

libsql/libsql-sqlite3/src/func.c

Line 23 in af82397

#include "vdbeInt.h"

Here is some docs:

libsql/libsql-sqlite3/src/vdbeInt.h

Lines 374 to 398 in be6a38f

	/*
	** The "context" argument for an installable function. A pointer to an
	** instance of this structure is the first argument to the routines used
	** implement the SQL functions.
	**
	** There is a typedef for this structure in sqlite.h. So all routines,
	** even the public interface to SQLite, can use a pointer to this structure.
	** But this file is the only place where the internal details of this
	** structure are known.
	**
	** This structure is defined inside of vdbeInt.h because it uses substructures
	** (Mem) which are only defined there.
	*/
	struct sqlite3_context {
	Mem *pOut; /* The return value is stored here */
	FuncDef *pFunc; /* Pointer to function information */
	Mem *pMem; /* Memory cell used to store aggregate context */
	Vdbe *pVdbe; /* The VM that owns this context */
	int iOp; /* Instruction number of OP_Function */
	int isError; /* Error code returned by the function. */
	u8 enc; /* Encoding to use for results */
	u8 skipFlag; /* Skip accumulator loading if true */
	u8 argc; /* Number of arguments */
	sqlite3_value *argv[1]; /* Argument set */
	};