### Set up Docusaurus documentation server

Source: https://github.com/github/codeql/blob/main/go/ql/test/library-tests/semmle/go/frameworks/Twirp/vendor/github.com/twitchtv/twirp/CONTRIBUTING.md

Install and start the local Docusaurus server to preview documentation changes before publishing. Navigate to http://localhost:3000/twirp after starting.

```bash
cd website
```

```bash
npm install
```

```bash
npm start
```

--------------------------------

### Bash script for CodeQL integration test setup

Source: https://github.com/github/codeql/blob/main/python/extractor/cli-integration-test/README.md

This script provides a robust starting point for `test.sh` files in new integration test cases, ensuring strict error handling and proper directory navigation.

```bash
#!/bin/bash

set -Eeuo pipefail # see https://vaneyckt.io/posts/safer_bash_scripts_with_set_euxo_pipefail/

set -x

CODEQL=${CODEQL:-codeql}

SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
cd "$SCRIPTDIR"
```

--------------------------------

### Run Django Migrations and Development Server

Source: https://github.com/github/codeql/blob/main/python/ql/test/library-tests/frameworks/rest_framework/README.md

These commands prepare the database and start the local development server for a Django project. They should be executed after initial project setup.

```bash
python manage.py makemigrations
python manage.py migrate
python manage.py runserver
```

--------------------------------

### Install CodeQL Pack Dependencies

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-overview/codeql-changelog/codeql-cli-2.6.0.md

Installs all dependencies specified in the `qlpack.yml` file for the current CodeQL pack.

```bash
codeql pack install
```

--------------------------------

### QL Order Comparison Examples

Source: https://github.com/github/codeql/blob/main/docs/codeql/query-help/ql-language-reference/formulas.md

Examples demonstrating the use of order comparison operators in QL, showing formulas that evaluate to true.

```ql
"Ann" < "Anne"
```

```ql
5 + 6 >= 11
```

--------------------------------

### Start MongoDB daemon with configuration

Source: https://github.com/github/codeql/blob/main/python/ql/test/query-tests/Security/CWE-943-NoSqlInjection/PoC/readme.md

Start the MongoDB server using mongod with a configuration file and fork to background process.

```bash
mongod --config /usr/local/etc/mongod.conf --fork
```

--------------------------------

### QL String Literal Examples

Source: https://github.com/github/codeql/blob/main/docs/codeql/ql-training/ql-language-reference/ql-language-specification.md

Provides examples of string literals in QL, including basic strings and those with escaped double quotes.

```none
"hello"
"He said, \"Logic clearly dictates that the needs of the many...\""
```

--------------------------------

### QL Integer Literal Examples

Source: https://github.com/github/codeql/blob/main/docs/codeql/ql-training/ql-language-reference/ql-language-specification.md

Illustrates examples of valid integer literals in QL, including positive, zero, and negative values.

```none
0
42
123
-2147483648
```

--------------------------------

### Query Example - List Methods in a Class

Source: https://github.com/github/codeql/blob/main/docs/codeql/query-help/codeql-language-guides/codeql-library-for-ruby.md

Example CodeQL query demonstrating how to list all methods in the ApiController class using the ClassDeclaration and getAMethod() predicate.

```APIDOC
## Query Example - List Methods in a Class

### Description
Lists all methods in the class ApiController.

### Query
```ql
import codeql.ruby.AST

from ClassDeclaration m
where m.getName() = "ApiController"
select m, m.getAMethod()
```

### Usage
This query imports the CodeQL Ruby AST library and finds all ClassDeclaration nodes where the name equals "ApiController", then returns the class declaration and all methods within it.
```

--------------------------------

### Install retool via go get

Source: https://github.com/github/codeql/blob/main/go/ql/test/library-tests/semmle/go/frameworks/Twirp/vendor/github.com/twitchtv/twirp/CONTRIBUTING.md

Install the retool dependency manager when `make setup` fails. Used for managing linters and other tools in the Twirp project.

```bash
go get github.com/twitchtv/retool
```

--------------------------------

### Install pre-commit framework and hooks

Source: https://github.com/github/codeql/blob/main/docs/pre-commit-hook-setup.md

Install the pre-commit framework via pip and initialize hooks in the repository. Requires pip and CodeQL CLI in PATH.

```bash
python3 -m pip install pre-commit
pre-commit install
```

--------------------------------

### QL Identifier Examples

Source: https://github.com/github/codeql/blob/main/docs/codeql/ql-training/ql-language-reference/ql-language-specification.md

Provides examples of valid identifiers in QL, including those starting with a letter or an '@' sign.

```none
width
Window_width
window5000_mark_II
@expr
```

--------------------------------

### Examples of QL 'any' expressions

Source: https://github.com/github/codeql/blob/main/docs/codeql/ql-language-reference/expressions.md

These examples demonstrate various forms of the `any` expression in QL, showing how to retrieve files, element names, and sequences of integers or their transformations.

```ql
any(File f)
```

```ql
any(Element e | e.getName())
```

```ql
any(int i | i = [0 .. 3])
```

```ql
any(int i | i = [0 .. 3] | i * i)
```

--------------------------------

### Find all Python functions starting with 'get' using CodeQL

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/functions-in-python.md

This query identifies all functions whose names begin with 'get'. It often returns many results, including functions that are not methods.

```ql
import python

from Function f
where f.getName().matches("get%")
select f, "This is a function called get..."
```

--------------------------------

### Set up and run Twirp tests

Source: https://github.com/github/codeql/blob/main/go/ql/test/library-tests/semmle/go/frameworks/Twirp/vendor/github.com/twitchtv/twirp/CONTRIBUTING.md

Standard workflow for building and testing Twirp. Run `make` to install dependencies, build core, and run tests. Use `make test` for Go unit tests only.

```bash
make
```

```bash
make test
```

--------------------------------

### QLDoc Comment Example

Source: https://github.com/github/codeql/blob/main/docs/codeql/ql-training/ql-language-reference/ql-language-specification.md

Illustrates the structure of a QLDoc comment, starting with '/**' and ending with '*/', with leading asterisks on internal lines.

```none
/**
  It was the best of code.
  It was the worst of code.
  It had a qldoc comment.
*/
```

--------------------------------

### Initialize a CodeQL Pack

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-overview/codeql-changelog/codeql-cli-2.6.0.md

Creates an empty CodeQL pack from a template, setting up the necessary structure for a new pack.

```bash
codeql pack init
```

--------------------------------

### Example Python If/Elif/Else Structure

Source: https://github.com/github/codeql/blob/main/python/extractor/tsg-python/README.md

Sample Python code demonstrating the if/elif/else syntax that gets unrolled by the parser into nested if statements.

```python
if x: do_x
elif y: do_y
elif z: do_z
else: do_else
```

--------------------------------

### Enable Sandwiched Tracing for CodeQL Database Initialization

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-overview/codeql-changelog/codeql-cli-2.6.0.md

Use the `--begin-tracing` argument with `codeql database init` to enable sandwiched tracing, which is useful for CI systems that cannot wrap build actions directly.

```bash
codeql database init --begin-tracing
```

--------------------------------

### Find all Python methods starting with 'get' using CodeQL

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/functions-in-python.md

Refine the search to only include methods by using the `Function.isMethod()` predicate. This helps filter out non-method functions.

```ql
import python

from Function f
where f.getName().matches("get%") and f.isMethod()
select f, "This is a method called get..."
```

--------------------------------

### Manage CodeQL Starter Workspace with Git Submodules

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-for-visual-studio-code/setting-up-codeql-in-visual-studio-code.rst

These commands are used to clone the CodeQL starter repository with its submodules and to keep those submodules updated.

```bash
git clone --recursive
```

```bash
git submodule update --init --remote
```

```bash
git submodule update --remote
```

--------------------------------

### Access path example with nested components

Source: https://github.com/github/codeql/blob/main/ruby/ql/docs/flow_summaries.md

Example access path demonstrating nested component syntax. Shows how to reference the return value of an element at a specific index within an array argument.

```ql
Argument[0].Element[1].ReturnValue
```

--------------------------------

### Inefficient predicate for comparing elements in QL

Source: https://github.com/github/codeql/blob/main/docs/codeql/ql-training/writing-codeql-queries/troubleshooting-query-performance.md

This predicate compares two elements based on their name, file, and start line. It is presented as an example of a predicate that can be optimized by folding.

```ql
predicate similar(Element e1, Element e2) {
  e1.getName() = e2.getName() and
  e1.getFile() = e2.getFile() and
  e1.getLocation().getStartLine() = e2.getLocation().getStartLine()
}
```

--------------------------------

### CodeQL Query for Basic Python Getter Detection

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/expressions-and-statements-in-python.md

Identifies Python methods that start with 'get', are marked as methods, and contain only a single statement. This serves as a preliminary detection for getter-like functions.

```ql
import python

from Function f
where f.getName().matches("get%") and f.isMethod()
    and count(f.getAStmt()) = 1
select f, "This function is (probably) a getter."
```

--------------------------------

### Basic CodeQL Query Structure for Ruby

Source: https://github.com/github/codeql/blob/main/docs/codeql/query-help/codeql-language-guides/basic-query-for-ruby-code.md

Illustrates the fundamental components of a CodeQL query, including import, variable declaration, conditions, and result selection, using a Ruby AST example.

```ql
import codeql.ruby.AST
```

```ql
from IfExpr ifexpr
```

```ql
where not exists(ifexpr.getThen())
```

```ql
select ifexpr, "This 'if' expression is redundant."
```

--------------------------------

### Find single-statement Python methods starting with 'get' using CodeQL

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/functions-in-python.md

Further refine the query to find methods with a single statement body, often indicative of simple getters. It uses `count(f.getAStmt()) = 1`.

```ql
import python

from Function f
where f.getName().matches("get%") and f.isMethod()
 and count(f.getAStmt()) = 1
select f, "This function is (probably) a getter."
```

--------------------------------

### Install QL Emacs Modes

Source: https://github.com/github/codeql/blob/main/misc/emacs/README.md

Add the QL Emacs directory to the 'load-path' and require the 'ql-mode-base' and 'dbscheme-mode' in your Emacs initialization file.

```elisp
;  ~/.emacs, ~/.emacs.el, or ~/.emacs.d/init.el

; ...

(add-to-list 'load-path "~/ql/misc/emacs")
(require 'ql-mode-base)
(require 'dbscheme-mode)

; ...
```

--------------------------------

### Example Project Configuration for Flask

Source: https://github.com/github/codeql/blob/main/python/tools/recorded-call-graph-metrics/README.md

Illustrates the JSON configuration structure for adding a new project like Flask to the tracing system. It specifies the repository, commit SHA, test command, and setup steps.

```json
    "flask": {
        "repo": "https://github.com/pallets/flask.git",
        "sha": "21c3df31de4bc2f838c945bd37d185210d9bab1a",
        "module_command": "pytest -c /dev/null tests examples",
        "setup": [
            "pip install -r requirements/tests.txt",
            "pip install -q -e examples/tutorial[test]",
            "pip install -q -e examples/javascript[test]"
        ]
    }
```

--------------------------------

### Import CodeQL Go Libraries

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/basic-query-for-go-code.md

Every CodeQL query begins with one or more import statements to include standard libraries, such as the Go libraries in this example.

```ql
import go
```

--------------------------------

### Query Example - List All Jobs in Named Workflow

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/codeql-library-for-actions.md

A practical CodeQL query example that demonstrates how to retrieve all jobs from a workflow with a specific name declaration. This example shows how to combine the getName() and getAJob() predicates.

```APIDOC
## Query: List All Jobs in Workflow Named "test"

### Description
This query retrieves all jobs from workflows with the name declaration `name: test`.

### Query Code
```ql
import actions

from Workflow w
where w.getName() = "test"
select w, w.getAJob()
```

### Query Explanation
- **import actions** - Imports the CodeQL actions library containing the Workflow class
- **from Workflow w** - Iterates over all Workflow objects
- **where w.getName() = "test"** - Filters workflows with the name "test"
- **select w, w.getAJob()** - Returns the workflow and each of its jobs

### Results
The query returns tuples containing:
- The Workflow object matching the name filter
- Each Job object within that workflow
```

--------------------------------

### CodeQL Path Query for Network Input to File System (Python)

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/analyzing-data-flow-in-python.md

This path query version of the network input example identifies the full data flow path from remote input to file system access. It uses `@kind path-problem` to visualize the flow.

```ql
/**
 * @kind path-problem
 * @problem.severity warning
 * @id file-system-access-from-remote-input
 */

import python
import semmle.python.dataflow.new.DataFlow
import semmle.python.dataflow.new.TaintTracking
import semmle.python.dataflow.new.RemoteFlowSources
import semmle.python.Concepts

module RemoteToFileConfiguration implements DataFlow::ConfigSig {
  predicate isSource(DataFlow::Node source) {
    source instanceof RemoteFlowSource
  }

  predicate isSink(DataFlow::Node sink) {
    sink = any(FileSystemAccess fa).getAPathArgument()
  }
}

module RemoteToFileFlow = TaintTracking::Global<RemoteToFileConfiguration>;

import RemoteToFileFlow::PathGraph

from RemoteToFileFlow::PathNode input, RemoteToFileFlow::PathNode fileAccess
where RemoteToFileFlow::flowPath(input, fileAccess)
select fileAccess.getNode(), input, fileAccess, "This file access uses data from $@.",
  input, "user-controllable input."
```

--------------------------------

### Install ripunzip with Bazel to a custom directory

Source: https://github.com/github/codeql/blob/main/misc/ripunzip/README.md

Use this command to specify a custom installation directory for ripunzip.

```bash
bazel run //misc/ripunzip:install -- /path/to/installation/dir
```

--------------------------------

### QL Equality Comparison Examples

Source: https://github.com/github/codeql/blob/main/docs/codeql/query-help/ql-language-reference/formulas.md

Examples illustrating the use of equality and inequality operators in QL, showing formulas that evaluate to true under specific conditions or always.

```ql
x.sqrt() = 2
```

```ql
4 != 5
```

--------------------------------

### Property Pluralization Examples

Source: https://github.com/github/codeql/blob/main/misc/codegen/schema_documentation.md

Examples of property definitions illustrating how pluralization is handled for auto-generated documentation and when `doc()` is used.

```python
generic_type_params: list[GenericTypeParamDecl]
arguments: list[Argument] | doc("arguments passed to the applied function")
```

--------------------------------

### Execute `cg-trace` for a Simple Example

Source: https://github.com/github/codeql/blob/main/python/tools/recorded-call-graph-metrics/README.md

Demonstrates how to run the `cg-trace` tool on a Python script, outputting the call graph to an XML file. This is a basic usage example for local testing.

```bash
cg-trace --xml example/simple.xml example/simple.py
```

--------------------------------

### QL Type Check Example

Source: https://github.com/github/codeql/blob/main/docs/codeql/query-help/ql-language-reference/formulas.md

An example demonstrating how to use the `instanceof` operator to check the type of a variable in QL.

```ql
x instanceof Person
```

--------------------------------

### Install ripunzip with Bazel to default location

Source: https://github.com/github/codeql/blob/main/misc/ripunzip/README.md

Use this command to install ripunzip to the default location, typically ~/.local/bin.

```bash
bazel run //misc/ripunzip:install
```

--------------------------------

### Redundant If Statement Example in C#

Source: https://github.com/github/codeql/blob/main/docs/codeql/codeql-language-guides/basic-query-for-csharp-code.md

Example of C# code with an empty if statement branch that the CodeQL query is designed to detect.

```csharp
if (error) { }
```