Changing a structs string - c

Question

I'm using lex to implement a scanner. I want to build a symbol table while parsing. I have two structs, SymbolEntry and SymbolTable (below). Most of the time, when I call my function for inserting a symbol (registerID, also below) I have all the information for the entry. However, when I have a constant I also want to get it's value, but that is not immediately available when I first create the entry. When I try to change the entries value later in the code, I'm invalidating the whole memory block used by that entry and the name and value are printing garbage.
Here are the two structs:
typedef struct{
char* type;
char* name;
char* value;
} SymbolEntry;
typedef struct{
SymbolEntry *entries;
size_t size;
size_t capacity;
} SymbolTable;
This is the registerID function, called when an {id} is matched. yytext contains the ID.
int registerID(char* type){
//create a new symbol entry with the specified type and name and a default value
SymbolEntry e;
e.type = type;
e.name = (char *)calloc(yyleng+1, sizeof(char));
strcpy(e.name, yytext);
e.value = "";
prevSym = insertSymbol(&table, e);
return prevSym;
}
This is the relevant code for insertSymbol(SymbolTable* st, SymbolEntry entry). pos is always the last element in the array when inserting (otherwise the entry isn't unique and pos is just returned).
st->entries[pos].name = (char *)calloc(strlen(entry.name)+1, sizeof(char));
st->entries[pos].type = (char *)calloc(strlen(entry.type)+1, sizeof(char));
st->entries[pos].value = (char *)calloc(strlen(entry.value)+1, sizeof(char));
strcpy(st->entries[pos].name, entry.name);
strcpy(st->entries[pos].type, entry.type);
strcpy(st->entries[pos].value, entry.value);
Later, after the lex framework has matched the value immediately following a CONSTANTs name, this code is performed (directly in the rule for <CONSTANT_VAL>{number})
table.entries[prevSym].value = (char *)calloc(yyleng+1, sizeof(char));
strcpy(table.entries[prevSym].value, yytext);
Why does this invalidate the the SymbolEntry at this position in the array, and how can I safely change the contents of value?
EDIT:
It doesn't only happen with constants. The first two SymbolEntrys are always garbage. I'm assuming that probably means they ALL are, but the others just haven't been overwritten.
Also, it seems like subsequent calls to registerID is causing the data to get corrupted. With just 9 symbols, only the first two are garbage, with 34, it's the first 7. Adding more text to parse without variables did not cause any issues.
SOLVED
Well it turns out that I just accidentally deleted a line somewhere along the way and that's what introduced the bug. I accidentally erased my call to initSymbolTable. Thanks to chux for asking me how I initialized the table. Sorry about that.

Answer 1

2 potential problems.
1 - Compare
// Fields set with non-malloc'ed memory
e.type = type;
e.value = "";
// Fields set with malloc'ed memory
st->entries[pos].type = (char *)calloc(strlen(entry.type)+1, sizeof(char));
st->entries[pos].value = (char *)calloc(strlen(entry.value)+1, sizeof(char));
strcpy(st->entries[pos].type, entry.type);
strcpy(st->entries[pos].value, entry.value);
Both of these set the fields to valid memory and in the second case, dynamically fill the memory. The concern is subsequent use. How does OP know to free() or realloc() the second kind and not the first. Further concern: With registerID(char* type), how do we know the value passed to type is still valid way later when that pointer is used via field type. Suggest:
e.type = strdup(type); // or the usual strlen()+1, malloc() and copy
e.value = strdup("");
2 - The type and setting of yyleng are not shown. Maybe it is not big enough as compared to strlen(e.name), etc.?
[Edit] after review, I real think e.type = type; is the problem. e.type needs its own copy of type.
Minor: Consider
// st->entries[pos].type = (char *)calloc(strlen(entry.type)+1, sizeof(char));
// strcpy(st->entries[pos].type, entry.type);
size_t Length = strlen(entry.type) + 1;
st->entries[pos].type = malloc(Length);
memcpy(st->entries[pos].type, entry.type, Length);