feat: Add QSurv contract and tests by IanLaFlair · Pull Request #771 · qubic/core

IanLaFlair · 2026-02-19T15:08:16Z

Description

This PR introduces QSurv (Qubic Survey), a decentralized and verifiable survey smart contract integrated into the Qubic Core.

QSurv enables entities to create and fund surveys directly on the Qubic network. Respondents are then rewarded autonomously upon successful survey completion. Central to the contract is its Oracle integration, ensuring that off-chain survey data or respondent verification is securely bridged on-chain.

Key Features

Survey Creation: Entities can instantiate new surveys (createSurvey) by allocating a rewardPool, defining a max targetRespondents, and providing an IPFS hash containing the survey metadata/questions.
Oracle Governance: A trusted Oracle is assigned via setOracle to act as the ultimate judge for survey completions and reward distributions.
Automated Payouts: The payout function automatically distributes the base reward, platform fees (1%), and optional referral/bonus payouts to verified respondents.
Slot Reusability: Designed with MAX_SURVEYS limits in mind, the contract actively reuses inactive slots to prevent indefinite storage creep.

Updates (Addressing PR Feedback)

Resolved division edge-cases and precise routing for platform, referral, and base rewards to ensure exactly 100% of funds are accounted for without leaking or deflating the _surveys balance.
Patched an oracle hijacking vulnerability by immediately assigning _oracleAddress during the contract's INITIALIZE() routine.
Updated test/contract_qsurv.cpp to include comprehensive Google Tests covering success conditions, insufficient funds, permission rejections, and zero-value bounds.
Formatted all .h and .cpp files to adhere strictly to Qubic's Allman brace style guidelines.

IanLaFlair · 2026-02-19T15:08:28Z

ok

Franziska-Mueller · 2026-02-19T15:27:57Z

please use develop as base for your changes and make sure your code compiles without any warnings.

fnordspace · 2026-02-20T14:06:17Z

src/contract_core/contract_def.h

Please make sure you keep the existing format of the files. The new lines introduce a lot of noise in the changes.

Also please make sure you leave the #include order as is.

fnordspace · 2026-02-20T14:07:46Z

src/contract_core/contract_def.h

+
+#endif
+
 // new contracts should be added above this line


Please keep these guards as is as they will be removed in the development branch when we update it.

fnordspace · 2026-02-20T14:08:29Z

src/contract_core/contract_def.h

+
+#endif
+
+#define QSURV_CONTRACT_INDEX 25


You miss the #undef, see the other contracts above for the correct schema.

fnordspace

Overall a good start but there some major points that need to be addressed:

Please do not change the formating of files
Use the style described in https://github.com/qubic/core/blob/main/doc/contributing.md#style-guidelines for your Contract
The PR description should clearly describe the SC functionality or link to the proposal with the description.
src/Qubic.vcxproj and src/Qubic.vcxproj.filters: Adding the SC header file to the Qubic project in the VS Solution.
test/test.vcxproj and test/test.vcxproj.filters: Adding the SC test file to the test project in the VS Solution.
Make sure the UEFI and test build run without Errors and use the develop branch as base branch
Also make sure you check your contract with the Contract Verify tool https://github.com/qubic/core/blob/main/doc/contracts.md#review-and-tests, at the moment there are no problems in this regards.

fnordspace · 2026-02-20T14:09:33Z

src/contract_core/contract_def.h

+#define CONTRACT_STATE2_TYPE QSURV2
+#include "contracts/QSurv.h"
+
+#endif


This #endif has no coresponding #if probably a copy paste error from pulse. Leave the compile time switch away for the moment.

fnordspace · 2026-02-20T14:11:01Z

src/contract_core/contract_def.h

Also please make sure you leave the #include order as is.

fnordspace · 2026-02-20T14:43:15Z

src/contracts/QSurv.h

+    }
+
+    // Verify invocation reward matches rewardPool
+    if (qpi.invocationReward() < input.rewardPool) {


If the user send more Qus than needed, everything is kept. Can be ok but worth thinking about refund the excess back to the user.

fnordspace · 2026-02-20T14:55:25Z

src/contracts/QSurv.h

+
+  PUBLIC_PROCEDURE(setOracle) {
+    // Only allow setting oracle if not already set, or by current oracle
+    if (state._oracleAddress == NULL_ID ||


The first caller to this procedures can set the oracleAddress. Probably better to set the inital _oracleAddress in INITIALIZE so that no one can try to be faster and 'steal' the oracleAddress by setting it.

fnordspace · 2026-02-20T15:04:57Z

src/contracts/QSurv.h

+
+    // Calculate reward splits using QPI::div (no / operator allowed)
+    locals.totalReward = locals.tempSurvey.rewardPerRespondent;
+    locals.baseReward =


Would be nice to see a bit more detail how the payout is planned. At the moment the total amount only accounts for 90% (60% Base, 25% Referral, 5% Platform) but 100% are deducted from the survey balance.

Also it is not clear to me how the bonus system works, in its current form it might deplete the contracts Qus over time.

fnordspace · 2026-02-20T15:10:40Z

src/contracts/QSurv.h

Maybe worth to check if you want to have a way to cancel surveys if not enough people are answering. Also at the moment there will be a maximum of 1024 contracts ever before the contract is rendered useless completed surveys are never cleaned and the slot remains occupied.

Please also make sure your contract follows the style guide https://github.com/qubic/core/blob/main/doc/contributing.md#style-guidelines

fnordspace · 2026-02-20T15:15:30Z

test/contract_qsurv.cpp

Great that you test, test could be more thorough tho. Some ideas on top of my mind:

Verify the expected survey and contract balance after payout

Survey competition works as expected e.g., isActive => 0

createSurvey with maxRespondents = 0 or rewardPool = 0

Set oracle from non oracle id (should fail)

Payout when currentRespondents >= maxRespondents (should fail)

IanLaFlair · 2026-02-21T03:38:32Z

Hi @fnordspace, I have updated the PR to address the feedback. I've patched the potential vulnerabilities in

setOracle, updated the exact payout logic to prevent deflation/division issues, thoroughly expanded the test suites in contract_qsurv.cpp, and adhered to the Allman formatting guidelines. I also resolved the recent merge conflicts

fnordspace · 2026-02-21T05:54:11Z

@IanLaFlair Thanks for the update. I'll take a look later. However the last commit also includes your build directory and hence adds around 200 files. Please do not commit these. Also see my other comments about changing the format of, for example, contract_def.h.

fnordspace

The PR is not in a state for a proper review. The code will not compile in it current version and style restrictions are not followed. Please first fix all the issues, make sure it compiles with MSVC (not cmake/clang) and that all tests runs.

I strongly suggest you test your SC functionality thoroughly as in the moment I don't think it is doing what you expect. To test your SC you can use the Qubic Core-Lite https://github.com/qubic/core-lite. This node you can run in single node mode and test your SC in a ticking network.

fnordspace · 2026-02-21T11:30:29Z

src/contract_core/contract_def.h

+                  "Size of contract state " #contractName " is too large!");   \
+  }
+
+<<<<<<< HEAD static void initializeContracts() {


These are git conflict marker, should not be here

fnordspace · 2026-02-21T11:30:38Z

src/contract_core/contract_def.h

+#endif
+  REGISTER_CONTRACT_FUNCTIONS_AND_PROCEDURES(QSURV);
+  // new contracts should be added above this line
+  == == == =


fnordspace · 2026-02-21T11:30:47Z

src/contract_core/contract_def.h

    REGISTER_CONTRACT_FUNCTIONS_AND_PROCEDURES(QTF);
    REGISTER_CONTRACT_FUNCTIONS_AND_PROCEDURES(QDUEL);
    // new contracts should be added above this line
+>>>>>>> upstream/develop


fnordspace · 2026-02-21T11:31:41Z

src/contracts/QSurv.h

+  // ============================================
+public:
+  INITIALIZE() {
+    state._oracleAddress = qpi.invocator();


INITIALIZE() has no invocator hence it probably will set the oracleAddress to null leaving the same problem open.

Franziska-Mueller · 2026-02-23T12:49:53Z

@IanLaFlair Do not force-push after we've started reviewing/writing comments. The force-push destroys the association of the comments with the code and we're unable to see the changes you introduce with new commits.

…ract_def.h formatting

…and contract_def.h registration

…_pulse.cpp

IanLaFlair · 2026-02-25T07:36:50Z

@Franziska-Mueller Hi Franziska, thanks for the guidance!
I've addressed all the feedback and pushed

…ain pristine CRLF line endings

…oj files

…er hijacking

Franziska-Mueller changed the base branch from main to develop February 19, 2026 15:21

Franziska-Mueller requested a review from fnordspace February 19, 2026 15:28

fnordspace reviewed Feb 20, 2026

View reviewed changes

fnordspace requested changes Feb 20, 2026

View reviewed changes

fnordspace requested changes Feb 21, 2026

View reviewed changes

feat: Add QSurv contract and tests

60fa7c4

IanLaFlair force-pushed the feature/QSurv branch from af183a3 to 60fa7c4 Compare February 21, 2026 14:42

IanLaFlair added 3 commits February 24, 2026 15:59

fix(qsurv): resolve MSVC test compile issue and restore pristine cont…

75a1feb

…ract_def.h formatting

fix(qsurv): fix MSVC C2327 type collision, signed/unsigned mismatch, …

30ce184

…and contract_def.h registration

fix(qsurv): fix MSVC errors - QPI::Array, getBalance, remove contract…

1aadaf5

…_pulse.cpp

fix(qsurv): add missing NO_UEFI define to test file to fix MSVC includes

5f3219e

IanLaFlair requested a review from fnordspace February 25, 2026 09:27

IanLaFlair added 4 commits March 2, 2026 22:51

fix: restore pristine contract_def.h

a25a504

fix(qsurv): perfectly re-inject contract_def.h registrations to maint…

c333e93

…ain pristine CRLF line endings

fix(qsurv): remove leftover Pulse test contract references from vcxpr…

9868efb

…oj files

feat(qsurv): hardcode Genesis Oracle ID in INITIALIZE to prevent snip…

4ff8682

…er hijacking


		#endif

		#define QSURV_CONTRACT_INDEX 25

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Description

Key Features

Updates (Addressing PR Feedback)

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IanLaFlair commented Feb 21, 2026

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IanLaFlair commented Feb 25, 2026

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