This converts the callback function defined on the internal opcode
struct to accept the opcode and data slice instead of a parsed opcode as
the final step towards removing the parsed opcode struct and associated
supporting code altogether.
It also updates all of the callbacks and tests accordingly and finally
removes the now unused parsedOpcode struct.
This converts the engine's current program counter disasembly to make
use of the standalone disassembly function to remove the dependency on
the parsed opcode struct.
It also updates the tests accordingly.
This removes the ScriptVerifyMinimalData flag from the txscript package,
changes the default semantics to always enforce its behavior, and
updates all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
It should be noted that the tests removed from script_tests.json
specifically dealt with ensuring equivalency of different ways to encode
the same numbers when the ScriptVerifyMinimalData flag is not set.
Therefore, they are no longer necessary.
A few tests which dealt with equivalency that did not already have
expected failing counterparts were converted to expected failure.
Also, several of the tests which dealt with ensuring the specific
encoding of numeric opcodes is being used have been converted to use
hashes since the minimal data requirements specifically prevent
alternate ways of pushing the same encoding which is necessary for
directly checking equality of the raw bytes.
Finally, the MINIMALDATA indicator to enable the flag in the test data
has been retained for now in order to isolate the logic changes as much
as possible.
This removes the ScriptVerifyDERSignatures flag from the txscript
package, changes the default semantics to always enforce its behavior
and updates all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
It should be noted that the tests removed from script_tests.json
specifically dealt with ensuring non-DER-compliant signatures were
handled properly when the ScriptVerifyDERSignatures flag was not set.
Therefore, they are no longer necessary.
Finally, the DERSIG indicator to enable the flag in the test data has
been retained for now in order to keep the logic changes separate.
This removes the ScriptBip16 flag from the txscript package, changes the
default semantics to always enforce its behavior, and updates all
callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so there is
no need to require a flag to conditionally toggle it.
Also, since it is no longer possible to invoke the script engine without
the flag with the clean stack flag, it removes the now unused
ErrInvalidFlags error and associated tests.
It should be noted that the test removed from script_tests.json
specifically dealt with ensuring a signature script that contained
non-data-pushing opcodes was successful when neither the ScriptBip16 or
ScriptVerifySigPushOnly flags were set. Therefore, it is no longer
necessary.
Finally, the P2SH indicator to enable the flag in the test data has been
retained for now in order to keep the logic changes separate.
This converts the majority of script errors from generic errors created
via errors.New and fmt.Errorf to use a concrete type that implements the
error interface with an error code and description.
This allows callers to programmatically detect the type of error via
type assertions and an error code while still allowing the errors to
provide more context.
For example, instead of just having an error the reads "disabled opcode"
as would happen prior to these changes when a disabled opcode is
encountered, the error will now read "attempt to execute disabled opcode
OP_FOO".
While it was previously possible to programmatically detect many errors
due to them being exported, they provided no additional context and
there were also various instances that were just returning errors
created on the spot which callers could not reliably detect without
resorting to looking at the actual error message, which is nearly always
bad practice.
Also, while here, export the MaxStackSize and MaxScriptSize constants
since they can be useful for consumers of the package and perform some
minor cleanup of some of the tests.
This removes the ScriptVerifyStrictEncoding flag from the txscript
package, changes the default semantics to always enforce its behavior
and updates all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
It should be noted that the tests removed from script_valid.json
specifically dealt with ensuring signatures not compliant with DER
encoding did not cause execution to halt early on invalid signatures
when neither of the ScriptVerifyStrictEncoding or
ScriptVerifyDERSignatures flags were set. Therefore, they are no longer
necessary.
For nearly the same reason, the tx test related to the empty pubkey
tx_valid.json was moved to tx_invalid.json. In particular, an empty
pubkey without ScriptVerifyStrictEncoding simply failed the signature
check and continued execution, while the same condition with the flag
halts execution. Thus, without the flag the final NOT in the script
would allow the script to succeed, while it does not under the strict
encoding rules.
Finally, the STRICTENC indicator to enable the flag in the test data has
been retained for now in order to keep the logic changes separate.
This removes the ScriptVerifyLowS flag from the txscript package,
changes the default semantics to always enforce its behavior and updates
all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
This modifies the script engine to replace OP_NOP3 with
OP_CHECKSEQUENCEVERIFY and adds a flag to selectively enable its
enforcement.
The new opcode examines the top item on the stack and compares it
against the sequence number of the associated transaction input in order
to allow scripts to conditionally enforce the inclusion of relative time
locks to the transaction.
The following is an overview of the changes:
- Introduce a new flag named ScriptVerifyCheckSequenceVerify to
provide conditional enforcement of the new opcode
- Introduce a constant named OP_CHECKSEQUENCEVERIFY which has the same
value as OP_NOP3 since it is replacing it
- Update opcode to name mappings accordingly
- Abstract the logic that deals with time lock verification since it is
the same for both the new opcode and OP_CHECKLOCKTIMEVERIFY
- Implement the required opcode semantics
- Add tests to ensure the opcode works as expected including when used
both correctly and incorrectly
This reverts the changes related to the CheckSequenceVerify opcode that
were merged from upstream since additional changes are needed and it's
much cleaner to implement all of code related to the sequence locks in
the same PR which will be referenced by the DCP as opposed to being
split up in multiple.
This modifies the way standard verification flags are handled so that it
is possible to selectively enable them based on the result of agenda
votes.
First, it moves the StandardVerifyFlags constant from the txscript
package to the mempool/policy code and rename it to
BaseStandardVerifyFlags. As the TODO in the comment of the moved
constant indicated, these flags are policy related and thus really
belong in policy. Ideally there would be a completely separate policy
package, but since the policy code currently lives in mempool/policy.go,
the constant has been moved there.
Next, it introduces a new function named standardScriptVerifyFlags,
which accepts the chain as an argument and, for now, just returns the
BaseStandardVerifyFlags along with a nil error. This will allow
additional flags to be selectively enabled depending on the result of an
agenda vote.
Finally, it updates the mempool policy struct to require a closure for
obtaining the flags so it can remain decoupled from the chain which in
turn allows easier and more robust unit testing of mempool functionality
since it allows a mocks to be used.
This modifies the script engine to replace OP_UNKNOWN192 with OP_SHA256
along with a flag named ScriptVerifySHA256 to selectively enable its
enforcement.
The new opcode consumes the top item from the data stack, computes its
SHA-256, and pushes the resulting digest back to the data stack.
Since it requires an item on the data stack, execution will terminate
with an error when the stack is empty. This behavior differs from
OP_UNKNOWN192 which does not consume any elements from the data stack
and therefore makes this is hard-forking change when interpreted with
the new semantics due to the ScriptVerifySHA256 flag being set. Code to
selectively enable the opcode based on the result of an agenda vote will
be added in a separate commit.
This also includes tests to ensure the opcode works as expected
including when used both correctly and incorrectly.
Decred updated the semantics of this opcode to use blake256, but did not
rename the opcode to reflect that. This renames the opcode so that it
is clear that a blake256 hash is produced instead of a sha256 hash.
Upstream commit a6bf1d9850.
The merge commit modifies all of the encoded transactions in the test
data to use Decred native format and contains some other minor
modifications necessary to integrate with Decred.
Corrected or added many comments.
Update test code to follow format go vet wants.
The code doesn't pass the checks 100% yet. That will come in a later
commit but these all seemed related so I'd rather get them in now.
See https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki for
more information.
This commit mimics Bitcoin Core commit bc60b2b4b401f0adff5b8b9678903ff8feb5867b
and includes additional tests from Bitcoin Core commit
cb54d17355864fa08826d6511a0d7692b21ef2c9
- Remove all redundant opcode tests in favor of the JSON-based tests
in the data directory.
- Remove duplicate stack nip test
- Add new tests to data/script_invalid.json to exercise additional
negative error paths
- Remove old unneeded pubkey trace code from opcodeCheckSig
- Simplify and improve the disassembly print function
- Add new tests to directly test all individual opcode disassembly
- Add new tests to directly test opcode disabled function which does not
get invoked during ordinary execution
- Improve test coverage of opcode.go
This commit modifies the definition of the opcodes to their hex
counterparts rather than decimal since it is far more common to see
scripts in hex. This makes it easier when manually looking at script
dumps to correlate opcodes. However, since there are also cases where it
is useful to see the decimal value of the opcode, the decimal value has
been left as a comment. Obviously converting the numbers is trivial, but
it is handy when looking at the opcode definitions to already have it
there.
In addition, it syncs the opcodes with the latest Bitcoin Core internal
opcodes for completeness and modifies the tests accordingly.
This commit renames the Script type to Engine to better reflect its
purpose. It also renames the NewScript function to NewEngine to match.
This is being done because name Script for the engine is confusing since
it implies it is an actual script rather than the execution environment
for the script. It also paves the way for eventually supplying a
ParsedScript type which will be less likely to be confused with the
execution environment.
While moving the code, some additional variable names and comments have
been updated to better match the style used throughout the rest of the
code base. In addition, an attempt has been made to use consistent naming
of the engine as 'vm' instead of using different variables names as it was
previously.
Finally, the relevant engine code has been moved into a new file named
engine.go and related tests moved to engine_test.go.
This commit removes the unnecessary sigScript parameter from the
txscript.NewScript function. This has bothered me for a while because it
can and really should be obtained from the provided transaction and input
index. The way it was, the passed script could technically be different
than what is in the transaction. Obviously that would be an improper use
of the API, but it's safer and more convenient to simply pull it from the
provided transaction and index.
Also, since the function signature is changing anyways, make the input
index parameter come after the transaction which it references.
Remove ScriptCanonicalSignatures and use the new
ScriptVerifyDERSignatures flag. The ScriptVerifyDERSignatures
flag accomplishes the same functionality.
This commit contains the entire btcscript repository along with several
changes needed to move all of the files into the txscript directory in
order to prepare it for merging. This does NOT update btcd or any of the
other packages to use the new location as that will be done separately.
- All import paths in the old btcscript test files have been changed to the
new location
- All references to btcscript as the package name have been chagned to
txscript
This is ongoing work toward #214.
