ICCheck - Inconsistent Change Checker

ICCheck finds inconsistent changes in your copy-pasted codes!

ICCheck takes any 2 revisions in a Git repository, and reports possible inconsistent changes. Compare between HEAD and worktree for pre-commit changes, or between main and your feature branch to run last-second checks on Pull Requests.

Please note that the way of detecting copy-pasted codes (i.e. cloned codes) is heuristic, and therefore is not perfect. While ICCheck detects many cloned codes correctly, it may also detect many false-positives.

Installation

Command Line Interface (statically-linked binary)

• Download from the latest releases page.
• Or, build it from source: go install github.com/salab/iccheck@latest

GitHub Actions

See "GitHub Actions Usage" section below.

Editor Extensions

ICCheck utilizes LSP (Language Server Protocol) to support multiple editors.

Currently, the following extensions are available from the authors:

• VSCode: iccheck - Visual Studio Marketplace
• IntelliJ IDEA Ultimate: ICCheck - Inconsistency Check - IntelliJ IDEs Plugin | Marketplace

If your editor is LSP-compatible, download the binary and run iccheck lsp command to launch the Language Server.

CLI Usage

Quick start: Run ICCheck in a git repository, with some local changes.

$ iccheck
2024/11/26 22:43:13 INFO 22 change chunk(s) within 3 file(s) found. from="HEAD (d46bf7e87fb62877f0052534659589ecc4c8aa41)" to=WORKTREE
2024/11/26 22:43:13 INFO 5 clone(s) are likely missing consistent change.

Clone set #0 - 5 out of 6 clones are likely missing consistent change(s).
  Missing changes (5):
    pkg/lsp/handler.go:74 (L74-L74)
    pkg/lsp/handler.go:93 (L93-L93)
    pkg/lsp/handler.go:112 (L112-L112)
    pkg/lsp/handler.go:147 (L147-L147)
    pkg/lsp/handler.go:52 (L52-L52)
  Changed clones (1):
    pkg/lsp/handler.go:167 (L167-L167)

ICCheck has found changes between HEAD commit and the worktree, and found that you are possibly missing changes to the reported locations.

Running iccheck --help displays help message.

Finds inconsistent changes in your git changes.

Usage:
  iccheck [flags]
  iccheck [command]

Available Commands:
  help        Help about any command
  lsp         Starts ICCheck Language Server
  search      A low-level command to search for code clones

Flags:
      --algorithm string         Clone search algorithm to use (fleccs, ncdsearch) (default "fleccs")
      --disable-default-ignore   Disable default ignore configs
      --fail-code int            Exit code if it detects any inconsistent changes
      --format string            Format type (console, json, github) (default "console")
  -f, --from string              Base git ref to compare against. Usually earlier in time.
  -h, --help                     help for iccheck
      --ignore stringArray       Regexp of file paths (and its contents) to ignore.
                                 If specifying both file paths and contents ignore regexp, split them by ':'.
                                 Example (ignore dist directory): --ignore '^dist/'
                                 Example (ignore import statements in js files): --ignore '\.m?[jt]s$:^import'
      --log-level string         Log level (debug, info, warn, error)
  -r, --repo string              Source git directory (supports bare)
      --timeout-seconds int      Timeout for detecting clones in seconds (default 60)
  -t, --to string                Target git ref to compare from. Usually later in time.
                                 Can accept special value "WORKTREE" to specify the current worktree.
  -v, --version                  version for iccheck

Use "iccheck [command] --help" for more information about a command.

CLI Output Format

ICCheck outputs detected inconsistent changes to stdout, and other logging outputs to stderr.

Output format can be changed via the --format argument. Make sure to check --format json out for ease integration with other systems such as review bots.

For example, one can utilize jq to process the JSON stdout into the GitHub Actions annotation format.

iccheck --format json | jq -r '":::notice file=\(.filename),line=\(.start_l),endLine=\(.end_l),title=Possible missing change::Possible missing a consistent change here (L\(.start_l) - L\(.end_l), distance \(.distance))"'

GitHub Actions Usage

An example workflow file:

name: Change Check

on:
  push:
    branches:
      - 'main'
  pull_request:

jobs:
  iccheck:
    name: Change Check
    runs-on: ubuntu-latest
    steps:
      - uses: actions/setup-go@v5
      - name: Install ICCheck
        run: go install github.com/salab/iccheck@latest

      - uses: actions/checkout@v4
        with:
          fetch-depth: '0'
      - name: Determine refs
        run: |
          ICCHECK_FROM="${{ github.event_name == 'pull_request' && github.event.pull_request.base.ref || 'HEAD^' }}"
          ICCHECK_TO="HEAD"
      - name: Check for inconsistent changes
        run: iccheck --from "$ICCHECK_FROM" --to "$ICCHECK_TO" --format github

Editor Extensions

Install the extension. Then, edit any text files in a git-controlled directory. ICCheck will automatically run when you open or edit files, and display line warnings if you are likely missing changes to other similar lines.

You can set cursor to warnings and run 'Find References' to display all clone locations in the clone set. (For example, Shift+F12 in VSCode, Alt+F7 in IntelliJ)

Ignore Definitions

ICCheck reads from the following files to determine which files and/or lines to ignore, when calculating info / warnings.

1. ~/.config/.iccheckignore.{yaml,yml}
2. ${repoDir}/.iccheckignore.{yaml,yml}

The ignore definitions is a yaml array and syntax is as follows:

# The whole file should be a yaml array, each of which is a single ignore definition rule.

# "files" (if present) specifies which file paths to ignore.
# "patterns" (if present) specifies which file contents to ignore.
# Both keys use the golang regexp syntax: RE2
# For RE2 syntax, see: https://github.com/google/re2/wiki/syntax

# A rule to ignore all files under dist/ path.
- files:
    - '^dist/'

# A rule to ignore lines which match '^import' in any file.
- patterns:
    - '^import'

# A rule to ignore specific lines in .go files.
- files:
    - '\.go$'
  patterns:
    - '^package .+$'
    - '^import (.+ )?".+"$'
    - '^import \(\n(\s+(.+ )?".+"\n)*\)$'

There are some built-in default rules in ICCheck. See pkg/domain/ignore.go for the default rules. These default rules can be disabled by the --disable-default-ignore CLI option.