Test: Add script vectors for interpreter edges #36458

pull benthecarman wants to merge 1 commits into bitcoin:master from benthecarman:script-vectors-interpreter-edges changing 2 files +38 −1

benthecarman commented at 7:35 PM on October 7, 2026: contributor

Add script_tests.json and tx_invalid.json vectors for edge cases that other implementations have gotten wrong, including CSV with -2, IFDUP on negative zero, ROLL with duplicate values, a taproot output key that is not a valid x coordinate, and single-flag STRICTENC, LOW_S and NULLFAIL cases.

Some policy cases were only caught by the tx_valid harness adding flags back, which implementations copying the JSON don't replicate.

Related: #36455

These were discovered by finding gaps in an alternate implementation (bitcoin-s)

Test: Add script vectors for interpreter edges

Add script_tests.json and tx_invalid.json vectors for edge cases that
other implementations have gotten wrong, including CSV with -2, IFDUP
on negative zero, ROLL with duplicate values, a taproot output key
that is not a valid x coordinate, and single-flag STRICTENC, LOW_S and
NULLFAIL cases.

Some policy cases were only caught by the tx_valid harness adding
flags back, which implementations copying the JSON don't replicate.

5d2fb8d309

DrahtBot added the label Tests on Oct 7, 2026
DrahtBot commented at 7:35 PM on October 7, 2026: contributor


The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.



External sites
- Code coverage & benchmarks: https://corecheck.dev/bitcoin/bitcoin/pulls/36458
- Ralph review <img src=https://review.fish.foo/assets/bitcoin/bitcoin/36458.png alt="Ralph review status"> https://git.fish.foo/bitcoin/bitcoin/pulls/36458#author-ralph


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ACK darosior

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fametrano commented at 9:36 AM on October 9, 2026: contributor

I ran the new vectors at 5d2fb8d through btclib, a Python implementation I maintain. Every new script_tests.json row gives the expected result and error code. Each of the 4 new tx_invalid.json rows fails under its listed flag with the error its comment describes, and is valid with no flags.
fanquake commented at 6:22 AM on October 16, 2026: member

cc @instagibbs
darosior commented at 2:49 PM on October 22, 2026: member

Concept ACK. It's useful to know what re-implementations got wrong, as it's often non-obvious stuff we can better cover in our automated testing.

Type	Reviewers
ACK	darosior

in src/test/data/tx_invalid.json:239 in 5d2fb8d309

 235 | @@ -224,6 +236,10 @@
 236 |  [[["0000000000000000000000000000000000000000000000000000000000000100", 0, "-1 CHECKSEQUENCEVERIFY"]],
 237 |  "020000000100010000000000000000000000000000000000000000000000000000000000000000000000000040000100000000000000000000000000", "CHECKSEQUENCEVERIFY"],
 238 |  
 239 | +["Argument -2 with by-blockheight txin.nSequence=0, even though -2 has the disable flag bit set"],

darosior commented at 8:49 PM on October 22, 2026:

Isn't this one redundant with the script_tests.json one you added above?

benthecarman commented at 9:31 PM on October 22, 2026:

yeah i guess, being redundant doesn't really hurt here though

in src/test/data/script_tests.json:2616 in 5d2fb8d309

2612 | @@ -2616,6 +2613,8 @@
2613 |  ["CHECKSEQUENCEVERIFY tests"],
2614 |  ["", "CHECKSEQUENCEVERIFY", "CHECKSEQUENCEVERIFY", "INVALID_STACK_OPERATION", "CSV automatically fails on an empty stack"],
2615 |  ["-1", "CHECKSEQUENCEVERIFY", "CHECKSEQUENCEVERIFY", "NEGATIVE_LOCKTIME", "CSV automatically fails if stack top is negative"],
2616 | +["-2", "CHECKSEQUENCEVERIFY", "CHECKSEQUENCEVERIFY", "NEGATIVE_LOCKTIME", "CSV fails for any negative operand, even though -2 has the disable flag bit set"],

darosior commented at 8:51 PM on October 22, 2026:

Heh, nice. (Though the -1 vector would also catch this, but good to have it spelled out.)

in src/test/data/script_tests.json:1041 in 5d2fb8d309

1037 | @@ -1036,6 +1038,8 @@
1038 |  ["-2147483648", "1ADD 1", "P2SH,STRICTENC", "SCRIPTNUM", "Because we use a sign bit, -2147483648 is also 5 bytes"],
1039 |  ["2147483647", "1ADD 1SUB 1", "P2SH,STRICTENC", "SCRIPTNUM", "We cannot do math on 5-byte integers, even if the result is 4-bytes"],
1040 |  ["2147483648", "1SUB 1", "P2SH,STRICTENC", "SCRIPTNUM", "We cannot do math on 5-byte integers, even if the result is 4-bytes"],
1041 | +["0x05 0xff00000000", "1ADD DROP 1", "P2SH,STRICTENC", "SCRIPTNUM", "We cannot do math on 5-byte integers, even if the value fits in 1 byte when minimally encoded"],

darosior commented at 8:52 PM on October 22, 2026:

Nice.

darosior approved
darosior commented at 8:53 PM on October 22, 2026: member

ACK 5d2fb8d3098703bc4d23d582eb4987cb2dbeda7a

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#36455 Test: Add legacy script edge cases to taproot test

Test: Add script vectors for interpreter edges #36458

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