Merge branch 'main' into layout-contracts

.github/workflows/pr_approval.yml

@@ -0,0 +1,156 @@
+name: Check PR Approvals
+
+# For now, the workflow gets triggered only when a review is submitted
+# This technically means, a PR with zero approvals can be merged by the rules of this workflow alone
+# To protect against that scenario, we can turn on number of approvals required to 2 in the github settings
+# of the repository
+on:
+  pull_request_review:
+    types: [submitted]
+  workflow_dispatch:
+
+jobs:
+  check-approvals:
+    if: github.event.review.state == 'APPROVED' || github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install TOML parser
+        run: npm install @iarna/toml
+
+      - name: Check PR Relevance and Approvals
+        uses: actions/github-script@v6
+        with:
+          script: |
+            const fs = require('fs');
+            const toml = require('@iarna/toml');
+            const { owner, repo } = context.repo;
+            let pull_number;
+
+            if (github.event_name === 'workflow_dispatch') {
+              const branch = github.ref.replace('refs/heads/', '');
+              const prs = await github.rest.pulls.list({
+                owner,
+                repo,
+                head: `${owner}:${branch}`,
+                state: 'open'
+              });
+              if (prs.data.length === 0) {
+                console.log('No open PR found for this branch.');
+                return;
+              }
+              pull_number = prs.data[0].number;
+            } else {
+              pull_number = context.issue.number;
+            }
+
+            // Get PR files
+            const files = await github.rest.pulls.listFiles({
+              owner,
+              repo,
+              pull_number
+            });
+
+            const relevantPaths = ['library/', 'doc/src/challenges/'];
+            const isRelevantPR = files.data.some(file =>
+              relevantPaths.some(path => file.filename.startsWith(path))
+            );
+
+            if (!isRelevantPR) {
+              console.log('PR does not touch relevant paths. Exiting workflow.');
+              return;
+            }
+
+            // Get parsed data
+            try {
+              const tomlContent = fs.readFileSync('.github/pull_requests.toml', 'utf8');
+              console.log('TOML content:', tomlContent);
+              const tomlData = toml.parse(tomlContent);
+              console.log('Parsed TOML data:', JSON.stringify(tomlData, null, 2));
+
+              if (!tomlData.committee || !Array.isArray(tomlData.committee.members)) {
+                throw new Error('committee.members is not an array in the TOML file');
+              }
+              requiredApprovers = tomlData.committee.members;
+            } catch (error) {
+              console.error('Error reading or parsing TOML file:', error);
+              core.setFailed('Failed to read required approvers list');
+              return;
+            }
+
+            // Get all reviews
+            const reviews = await github.rest.pulls.listReviews({
+              owner,
+              repo,
+              pull_number
+            });
+
+            // Example: approvers = ["celina", "zyad"]
+            const approvers = new Set(
+              reviews.data
+                .filter(review => review.state === 'APPROVED')
+                .map(review => review.user.login)
+            );
+
+            const requiredApprovals = 2;
+            const requiredApproversCount = Array.from(approvers)
+              .filter(approver => requiredApprovers.includes(approver))
+              .length;
+
+            // TODO: Improve logging and messaging to the user
+            console.log('PR Approvers:', Array.from(approvers));
+            console.log('Required Approvers:', requiredApproversCount);
+
+            // Core logic that checks if the approvers are in the committee
+            const checkName = 'PR Approval Status';
+            const conclusion = (approvers.size >= requiredApprovals && requiredApproversCount >= 2) ? 'success' : 'failure';
+            const output = {
+              title: checkName,
+              summary: `PR has ${approvers.size} total approvals and ${requiredApproversCount} required approvals.`,
+              text: `Approvers: ${Array.from(approvers).join(', ')}\nRequired Approvers: ${requiredApprovers.join(', ')}`
+            };
+
+            // Get PR details
+            const pr = await github.rest.pulls.get({
+              owner,
+              repo,
+              pull_number
+            });
+
+            // Create or update check run
+            const checkRuns = await github.rest.checks.listForRef({
+              owner,
+              repo,
+              ref: pr.data.head.sha,
+              check_name: checkName
+            });
+
+            // Reuse the same workflow everytime there's a new review submitted
+            // instead of creating new workflows. Better efficiency and readability
+            // as the number of workflows is kept to a minimal number
+            if (checkRuns.data.total_count > 0) {
+              await github.rest.checks.update({
+                owner,
+                repo,
+                check_run_id: checkRuns.data.check_runs[0].id,
+                status: 'completed',
+                conclusion,
+                output
+              });
+            } else {
+              await github.rest.checks.create({
+                owner,
+                repo,
+                name: checkName,
+                head_sha: pr.data.head.sha,
+                status: 'completed',
+                conclusion,
+                output
+              });
+            }
+
+            if (conclusion === 'failure') {
+              core.setFailed(`PR needs at least ${requiredApprovals} total approvals and 2 required approvals. Current approvals: ${approvers.size}, Required approvals: ${requiredApproversCount}`);
+            }

doc/src/SUMMARY.md

@@ -16,3 +16,4 @@
   - [Core Transmutation](./challenges/0001-core-transmutation.md)
   - [Memory safety of core intrinsics](./challenges/0002-intrinsics-memory.md)
   - [Pointer Arithmetic](./challenges/0003-pointer-arithmentic.md)
+  - [Inductive data type](./challenges/0005-linked-list.md)

doc/src/challenges/0005-linked-list.md

@@ -0,0 +1,50 @@
+# Challenge 5: Verify functions iterating over inductive data type: `linked_list`
+
+- **Status:** Open
+- **Tracking Issue:** [Link to issue](https://github.com/model-checking/verify-rust-std/issues/29)
+- **Start date:** *24/07/01*
+- **End date:** *24/12/10*
+
+-------------------
+
+
+## Goal
+
+Verify the memory safety of [`alloc::collections::linked_list` functions](https://github.com/rust-lang/rust/blob/c290e9de32e8ba6a673ef125fde40eadd395d170/library/alloc/src/collections/linked_list.rs) that iterate the its internal inductive-defined data type.
+
+### Details
+
+The internal representations of `linked_list` are bi-direction linked list nodes. To unboundedly prove the memory safety of functions that iterating over such inductive-defined data type, we need to illustrate the memory safety for linked lists of arbitrary shape. On the other hand, if we can only prove the memory safety for certain shapes of linked lists, how should we specify the precondition---the assumptions on the shape of the inductive-defined data type---of such functions.  
+
+
+### Success Criteria
+
+The memory safety of the following public functions that iterating over the internal inductive data type must be verified:
+
+| Function | Location |
+|---------|---------|
+|clearn | alloc::collections::linked_list |
+|contains| alloc::collections::linked_list |
+|split_off| alloc::collections::linked_list |
+|remove| alloc::collections::linked_list |
+|retain| alloc::collections::linked_list |
+|retain_mut| alloc::collections::linked_list |
+|extract_if| alloc::collections::linked_list |
+
+
+The verification must be unbounded---it must hold for linked lists of arbitrary shape.
+
+It is OK to assume that the generic type `T` of the proofs is primitive types, e.g., `i32`, `u32`, `bool`, etc.
+
+### List of UBs
+
+All proofs must automatically ensure the absence of the following undefined behaviors [ref](https://github.com/rust-lang/reference/blob/142b2ed77d33f37a9973772bd95e6144ed9dce43/src/behavior-considered-undefined.md):
+
+* Accessing (loading from or storing to) a place that is dangling or based on a misaligned pointer.
+* Reading from uninitialized memory except for padding or unions.
+* Mutating immutable bytes.
+* Producing an invalid value
+
+
+Note: All solutions to verification challenges need to satisfy the criteria established in the [challenge book](../general-rules.md)
+in addition to the ones listed above.