improve on dao

vm/stdlib/modules/Dao.move

@@ -488,13 +488,13 @@ module Dao {
         let proposal = borrow_global_mut<Proposal<TokenT, ActionT>>(proposer_address);
 
         // get vote
-        let my_vote = borrow_global_mut<Vote<TokenT>>(Signer::address_of(signer));
+        let my_vote = move_from<Vote<TokenT>>(Signer::address_of(signer));
         {
             assert(my_vote.proposer == proposer_address, Errors::invalid_argument(ERR_PROPOSER_MISMATCH));
             assert(my_vote.id == proposal_id, Errors::invalid_argument(ERR_VOTED_OTHERS_ALREADY));
         };
         // revoke vote on proposal
-        let reverted_stake =do_revoke_vote(proposal, my_vote, voting_power);
+        let reverted_stake =do_revoke_vote(proposal, &mut my_vote, voting_power);
         // emit vote changed event
         let gov_info = borrow_global_mut<DaoGlobalInfo<TokenT>>(Token::token_address<TokenT>());
         Event::emit_event(
@@ -507,6 +507,15 @@ module Dao {
                 vote: Token::value(&my_vote.stake),
             },
         );
+
+        // if user has no stake, destroy his vote. resolve https://github.com/starcoinorg/starcoin/issues/2925.
+        if (Token::value(&my_vote.stake) == 0u128) {
+            let Vote {stake, proposer: _, id: _, agree: _} = my_vote;
+            Token::destroy_zero(stake);
+        } else {
+            move_to(signer, my_vote);
+        };
+
         reverted_stake
     }
 
@@ -823,6 +832,20 @@ module Dao {
         include CheckVoteOnProposal<TokenT>{vote, proposer_address, proposal_id};
     }
 
+    /// Check whether voter has voted on proposal with `proposal_id` of `proposer_address`.
+    public fun has_vote<TokenT: copy + drop + store>(
+        voter: address,
+        proposer_address: address,
+        proposal_id: u64,
+    ): bool acquires Vote {
+        if (!exists<Vote<TokenT>>(voter)) {
+            return false
+        };
+
+        let vote = borrow_global<Vote<TokenT>>(voter);
+        vote.proposer == proposer_address && vote.id == proposal_id
+    }
+
     fun generate_next_proposal_id<TokenT: store>(): u64 acquires DaoGlobalInfo {
         let gov_info = borrow_global_mut<DaoGlobalInfo<TokenT>>(Token::token_address<TokenT>());
         let proposal_id = gov_info.next_proposal_id;

vm/stdlib/modules/DaoVoteScripts.move

@@ -17,6 +17,16 @@ module DaoVoteScripts {
         agree: bool,
         votes: u128,
     ) {
+        let sender = Signer::address_of(&signer);
+        if (Dao::has_vote<Token>(sender, proposer_address, proposal_id)) {
+            // if already voted, and vote is not same as the current cast, change the existing vote.
+            // resolve https://github.com/starcoinorg/starcoin/issues/2925.
+            let (agree_voted, _) = Dao::vote_of<Token>(sender, proposer_address, proposal_id);
+            if (agree_voted != agree) {
+                Dao::change_vote<Token, ActionT>(&signer, proposer_address, proposal_id, agree);
+            }
+        };
+
         let votes = Account::withdraw<Token>(&signer, votes);
         Dao::cast_vote<Token, ActionT>(&signer, proposer_address, proposal_id, votes, agree);
     }
@@ -33,6 +43,16 @@ module DaoVoteScripts {
         Account::deposit(sender, my_token);
     }
 
+    /// Let user change their vote during the voting time.
+    public(script) fun flip_vote<TokenT: copy + drop + store, ActionT: copy + drop + store>(
+        signer: signer,
+        proposer_address: address,
+        proposal_id: u64,
+    ) {
+        let (agree, _) = Dao::vote_of<TokenT>(Signer::address_of(&signer), proposer_address, proposal_id);
+        Dao::change_vote<TokenT, ActionT>(&signer, proposer_address, proposal_id, !agree);
+    }
+
     /// revoke some votes on a proposal
     public ( script ) fun revoke_vote_of_power<Token: copy + drop + store, Action: copy + drop + store>(
         signer: signer,

vm/stdlib/modules/doc/Dao.md

@@ -30,6 +30,7 @@
 -  [Function `do_proposal_state`](#0x1_Dao_do_proposal_state)
 -  [Function `proposal_info`](#0x1_Dao_proposal_info)
 -  [Function `vote_of`](#0x1_Dao_vote_of)
+-  [Function `has_vote`](#0x1_Dao_has_vote)
 -  [Function `generate_next_proposal_id`](#0x1_Dao_generate_next_proposal_id)
 -  [Function `voting_delay`](#0x1_Dao_voting_delay)
 -  [Function `voting_period`](#0x1_Dao_voting_period)
@@ -913,13 +914,13 @@ Revoke some voting powers from vote on <code>proposal_id</code> of <code>propose
     <b>let</b> proposal = borrow_global_mut&lt;<a href="Dao.md#0x1_Dao_Proposal">Proposal</a>&lt;TokenT, ActionT&gt;&gt;(proposer_address);
 
     // get vote
-    <b>let</b> my_vote = borrow_global_mut&lt;<a href="Dao.md#0x1_Dao_Vote">Vote</a>&lt;TokenT&gt;&gt;(<a href="Signer.md#0x1_Signer_address_of">Signer::address_of</a>(signer));
+    <b>let</b> my_vote = move_from&lt;<a href="Dao.md#0x1_Dao_Vote">Vote</a>&lt;TokenT&gt;&gt;(<a href="Signer.md#0x1_Signer_address_of">Signer::address_of</a>(signer));
     {
         <b>assert</b>(my_vote.proposer == proposer_address, <a href="Errors.md#0x1_Errors_invalid_argument">Errors::invalid_argument</a>(<a href="Dao.md#0x1_Dao_ERR_PROPOSER_MISMATCH">ERR_PROPOSER_MISMATCH</a>));
         <b>assert</b>(my_vote.id == proposal_id, <a href="Errors.md#0x1_Errors_invalid_argument">Errors::invalid_argument</a>(<a href="Dao.md#0x1_Dao_ERR_VOTED_OTHERS_ALREADY">ERR_VOTED_OTHERS_ALREADY</a>));
     };
     // revoke vote on proposal
-    <b>let</b> reverted_stake =<a href="Dao.md#0x1_Dao_do_revoke_vote">do_revoke_vote</a>(proposal, my_vote, voting_power);
+    <b>let</b> reverted_stake =<a href="Dao.md#0x1_Dao_do_revoke_vote">do_revoke_vote</a>(proposal, &<b>mut</b> my_vote, voting_power);
     // emit vote changed event
     <b>let</b> gov_info = borrow_global_mut&lt;<a href="Dao.md#0x1_Dao_DaoGlobalInfo">DaoGlobalInfo</a>&lt;TokenT&gt;&gt;(<a href="Token.md#0x1_Token_token_address">Token::token_address</a>&lt;TokenT&gt;());
     <a href="Event.md#0x1_Event_emit_event">Event::emit_event</a>(
@@ -932,6 +933,15 @@ Revoke some voting powers from vote on <code>proposal_id</code> of <code>propose
             vote: <a href="Token.md#0x1_Token_value">Token::value</a>(&my_vote.stake),
         },
     );
+
+    // <b>if</b> user has no stake, destroy his vote. resolve https://github.com/starcoinorg/starcoin/issues/2925.
+    <b>if</b> (<a href="Token.md#0x1_Token_value">Token::value</a>(&my_vote.stake) == 0u128) {
+        <b>let</b> <a href="Dao.md#0x1_Dao_Vote">Vote</a> {stake, proposer: _, id: _, agree: _} = my_vote;
+        <a href="Token.md#0x1_Token_destroy_zero">Token::destroy_zero</a>(stake);
+    } <b>else</b> {
+        move_to(signer, my_vote);
+    };
+
     reverted_stake
 }
 </code></pre>
@@ -1304,6 +1314,40 @@ Get voter's vote info on proposal with <code>proposal_id</code> of <code>propose
 
 
 
+</details>
+
+<a name="0x1_Dao_has_vote"></a>
+
+## Function `has_vote`
+
+Check whether voter has voted on proposal with <code>proposal_id</code> of <code>proposer_address</code>.
+
+
+<pre><code><b>public</b> <b>fun</b> <a href="Dao.md#0x1_Dao_has_vote">has_vote</a>&lt;TokenT: <b>copy</b>, drop, store&gt;(voter: address, proposer_address: address, proposal_id: u64): bool
+</code></pre>
+
+
+
+<details>
+<summary>Implementation</summary>
+
+
+<pre><code><b>public</b> <b>fun</b> <a href="Dao.md#0x1_Dao_has_vote">has_vote</a>&lt;TokenT: <b>copy</b> + drop + store&gt;(
+    voter: address,
+    proposer_address: address,
+    proposal_id: u64,
+): bool <b>acquires</b> <a href="Dao.md#0x1_Dao_Vote">Vote</a> {
+    <b>if</b> (!<b>exists</b>&lt;<a href="Dao.md#0x1_Dao_Vote">Vote</a>&lt;TokenT&gt;&gt;(voter)) {
+        <b>return</b> <b>false</b>
+    };
+
+    <b>let</b> vote = borrow_global&lt;<a href="Dao.md#0x1_Dao_Vote">Vote</a>&lt;TokenT&gt;&gt;(voter);
+    vote.proposer == proposer_address && vote.id == proposal_id
+}
+</code></pre>
+
+
+
 </details>
 
 <a name="0x1_Dao_generate_next_proposal_id"></a>

vm/stdlib/modules/doc/DaoVoteScripts.md

@@ -7,6 +7,7 @@
 
 -  [Function `cast_vote`](#0x1_DaoVoteScripts_cast_vote)
 -  [Function `revoke_vote`](#0x1_DaoVoteScripts_revoke_vote)
+-  [Function `flip_vote`](#0x1_DaoVoteScripts_flip_vote)
 -  [Function `revoke_vote_of_power`](#0x1_DaoVoteScripts_revoke_vote_of_power)
 -  [Function `unstake_vote`](#0x1_DaoVoteScripts_unstake_vote)
 -  [Specification](#@Specification_0)
@@ -42,6 +43,16 @@
     agree: bool,
     votes: u128,
 ) {
+    <b>let</b> sender = <a href="Signer.md#0x1_Signer_address_of">Signer::address_of</a>(&signer);
+    <b>if</b> (<a href="Dao.md#0x1_Dao_has_vote">Dao::has_vote</a>&lt;<a href="Token.md#0x1_Token">Token</a>&gt;(sender, proposer_address, proposal_id)) {
+        // <b>if</b> already voted, and vote is not same <b>as</b> the current cast, change the existing vote.
+        // resolve https://github.com/starcoinorg/starcoin/issues/2925.
+        <b>let</b> (agree_voted, _) = <a href="Dao.md#0x1_Dao_vote_of">Dao::vote_of</a>&lt;<a href="Token.md#0x1_Token">Token</a>&gt;(sender, proposer_address, proposal_id);
+        <b>if</b> (agree_voted != agree) {
+            <a href="Dao.md#0x1_Dao_change_vote">Dao::change_vote</a>&lt;<a href="Token.md#0x1_Token">Token</a>, ActionT&gt;(&signer, proposer_address, proposal_id, agree);
+        }
+    };
+
     <b>let</b> votes = <a href="Account.md#0x1_Account_withdraw">Account::withdraw</a>&lt;<a href="Token.md#0x1_Token">Token</a>&gt;(&signer, votes);
     <a href="Dao.md#0x1_Dao_cast_vote">Dao::cast_vote</a>&lt;<a href="Token.md#0x1_Token">Token</a>, ActionT&gt;(&signer, proposer_address, proposal_id, votes, agree);
 }
@@ -81,6 +92,36 @@ revoke all votes on a proposal
 
 
 
+</details>
+
+<a name="0x1_DaoVoteScripts_flip_vote"></a>
+
+## Function `flip_vote`
+
+Let user change their vote during the voting time.
+
+
+<pre><code><b>public</b>(<b>script</b>) <b>fun</b> <a href="DaoVoteScripts.md#0x1_DaoVoteScripts_flip_vote">flip_vote</a>&lt;TokenT: <b>copy</b>, drop, store, ActionT: <b>copy</b>, drop, store&gt;(signer: signer, proposer_address: address, proposal_id: u64)
+</code></pre>
+
+
+
+<details>
+<summary>Implementation</summary>
+
+
+<pre><code><b>public</b>(<b>script</b>) <b>fun</b> <a href="DaoVoteScripts.md#0x1_DaoVoteScripts_flip_vote">flip_vote</a>&lt;TokenT: <b>copy</b> + drop + store, ActionT: <b>copy</b> + drop + store&gt;(
+    signer: signer,
+    proposer_address: address,
+    proposal_id: u64,
+) {
+    <b>let</b> (agree, _) = <a href="Dao.md#0x1_Dao_vote_of">Dao::vote_of</a>&lt;TokenT&gt;(<a href="Signer.md#0x1_Signer_address_of">Signer::address_of</a>(&signer), proposer_address, proposal_id);
+    <a href="Dao.md#0x1_Dao_change_vote">Dao::change_vote</a>&lt;TokenT, ActionT&gt;(&signer, proposer_address, proposal_id, !agree);
+}
+</code></pre>
+
+
+
 </details>
 
 <a name="0x1_DaoVoteScripts_revoke_vote_of_power"></a>