mirrors/ladybird
0
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-07-30 20:59:16 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

LibJS: Include identifier information in nullish property read access

Browse source 
When a GetById / GetByValue bytecode operation results in accessing a
nullish object, we now include the name of the property and the object
being accessed in the exception message (if available). This should make
it easier to debug live websites.

For example, the following errors would all previously produce a generic
error message of "ToObject on null or undefined":

  > foo = null
  > foo.bar
  Uncaught exception:
  [TypeError] Cannot access property "bar" on null object "foo"
      at <unknown>

  > foo = { bar: undefined }
  > foo.bar.baz
  Uncaught exception:
  [TypeError] Cannot access property "baz" on undefined object "foo.bar"
      at <unknown>

Note we certainly don't capture all possible nullish property read
accesses here. This just covers cases I've seen most on live websites;
we can cover more cases as they arise.
This commit is contained in:
Timothy Flynn 2024-03-29 11:26:10 -04:00 • committed by Andreas Kling
commit 9bbd3103a8
Notes: sideshowbarker 2024-07-16 23:03:06 +09:00
9 changed files with 137 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

10
Userland/Libraries/LibJS/Bytecode/Op.h
View file

@ -629,11 +629,12 @@ private:
class GetById final : public Instruction {
public:
GetById(Operand dst, Operand base, IdentifierTableIndex property, u32 cache_index)
GetById(Operand dst, Operand base, IdentifierTableIndex property, Optional<IdentifierTableIndex> base_identifier, u32 cache_index)
: Instruction(Type::GetById, sizeof(*this))
, m_dst(dst)
, m_base(base)
, m_property(property)
, m_base_identifier(move(base_identifier))
, m_cache_index(cache_index)
{
}
@ -650,6 +651,7 @@ private:
Operand m_dst;
Operand m_base;
IdentifierTableIndex m_property;
Optional<IdentifierTableIndex> m_base_identifier;
u32 m_cache_index { 0 };
};
@ -874,11 +876,12 @@ private:
class GetByValue final : public Instruction {
public:
explicit GetByValue(Operand dst, Operand base, Operand property)
GetByValue(Operand dst, Operand base, Operand property, Optional<IdentifierTableIndex> base_identifier = {})
: Instruction(Type::GetByValue, sizeof(*this))
, m_dst(dst)
, m_base(base)
, m_property(property)
, m_base_identifier(move(base_identifier))
{
}
@ -889,10 +892,13 @@ public:
Operand base() const { return m_base; }
Operand property() const { return m_property; }
Optional<DeprecatedFlyString const&> base_identifier(Bytecode::Interpreter const&) const;
private:
Operand m_dst;
Operand m_base;
Operand m_property;
Optional<IdentifierTableIndex> m_base_identifier;
};
class GetByValueWithThis final : public Instruction {