Setting up include-what-you-need (IWYU)

Use following instructions to install IWYU (https://include-what-you-use.org/) on Ubuntu 18.04.3 LTS:

sudo apt-get update
sudo apt-get install -y build-essential cmake git zlib1g-dev libncurses5-dev llvm-6.0-dev libclang-6.0-dev libclang-6.0-dev clang-6.0
git clone https://github.com/include-what-you-use/include-what-you-use.git iwyu.git
cd iwyu.git
git checkout clang_6.0
mkdir -p build
cd build
cmake -DIWYU_LLVM_ROOT_PATH=/usr/lib/llvm-6.0 ..
make 
make install

Once installation is complete, you will find `include-what-you-need`

# include-what-you-use --version
include-what-you-use 0.10 (git:a1878c4) based on clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)

To execute include-what-you-need:

Build your cpp project with cmake and pass on an extra parameter `-DCMAKE_EXPORT_COMPILE_COMMANDS=TRUE` to cmake. It will produceĀ  `compile_commands.json` file in your build folder for the project.

  • Execute `iwyu_tool.py -p </path/to/folder/having/compile_command.json>`. It may take time depending upon the code size.
  • `fix_includes` can be used to apply recommended changes.

To use it in VSCode add following to the `tasks.json`

{
    "label": "CXX Analysis -- iwyu",
    "detail": "Run IWYU tool for CPP project",
    "command": "iwyu_tool.py",
    "args": [
        "-p",
        "${workspaceRoot}/build"
    ],
    "presentation": {
        "echo": true,
        "reveal": "always",
        "focus": true,
        "panel": "shared",
        "showReuseMessage": true,
        "clear": false
    },
    "problemMatcher": "$gcc"
}

Ref: https://gist.github.com/aakbar5/268a2072138345893b7f82590dcc3d26

VisualStudio code & compile_commands.json

If you are working with C/C++ in VSCode, you will find that VSCode keeps on showing

"${workspaceFolder}/build/compile_commands.json" could not be found. 'includePath' from c_cpp_properties.json will be used instead.

This message is generated by vscode-cpptools. Although it is an optional file however vscode-cpptools keeps on showing error message that it is missing.

This message can easily be fixed if you are using CMake. To do so simply add following to your CMake configuration file.

# Generate compile_commands.json
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

rename git branches

Let’s rename a git branch locally & remotely.

Let’s assume that you got git repository with multiple branches and you want to mark a branch as a master whereas existing master to something else.

  • Make note of the branch names and their respective remote
git branch -vv
  • Goto server repo and switch default branch
git symbolic-ref HEAD refs/heads/new-master
  • Goto local repo, checkout master
git checkout master
  • Rename it locally
git branch -mv master something
  • Remove remote branch
git push origin --delete master
  • Set new remote
git branch --unset-upstream
git push --set-upstream origin something
  • Goto server repo and switch default branch
git symbolic-ref HEAD refs/heads/something
  • Switch to branch which is going to be new master
git checkout new-master
  • Rename this branch
git branch -mv new-master master
  • Remove remote branch
git push origin --delete new-master
  • Set new remote
git branch --unset-upstream
git push --set-upstream origin master
  • Goto server repo and switch default branch to master
git symbolic-ref HEAD refs/heads/master