KogenCredo.Diff.Git (KogenCredo v0.1.0)

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Read-only git access for the diff runner.

Git is always started with System.cmd/3 and an argument list, never through a shell. User input is validated before it reaches git: revision strings may only contain [A-Za-z0-9_./@{}~^+-], must not start with -, and must not contain .. inside a side; paths must be relative, free of control characters, .. segments and leading - or :. Pathspecs are interpreted relative to the --repo directory: when --repo is a subdirectory of the work tree, lib/ means <subdirectory>/lib/ (the prefix comes from git rev-parse --show-prefix) and is then anchored at the repository top (:(top)). Reported file names are always rooted at the repository top (--no-relative is forced, so a repository-local diff.relative setting cannot change them). A path that matches nothing in either the base or the head tree is an error, never an empty success. Inherited git routing and pathspec variables (GIT_DIR, GIT_WORK_TREE, GIT_INDEX_FILE, GIT_CONFIG_PARAMETERS, GIT_LITERAL_PATHSPECS, ...) are removed from git's environment, so --repo is always the repository that is read, also when run from a git hook. Revisions are resolved to full object ids first and only those ids are used afterwards. Only read-only rev-parse, merge-base, diff, hash-object and cat-file commands run; no Git objects, refs or repository files are written. Temporary files are cleaned up. Any git failure is returned as {:error, message}; control characters in git's messages are escaped so repository content cannot forge extra output lines.

Standard output and standard error are captured separately (through sh when it exists), so a git warning can never corrupt a -z listing or a file's contents. A revision name that is both a branch and a tag resolves by git's own precedence; pass a full ref or a SHA to be explicit.

Summary

Types

entry()
range()

Functions

changed_files(repo, base, head, paths)

Changed .ex files between two commits, with renames detected.

check_paths(repo, base, head, paths)

Fails unless every path (relative to repo) matches at least one file in the base or the head tree, so a wrong default (subproject, umbrella root) cannot yield an empty success.

parse_range(range)

Parses and validates A..B or A...B.

resolve(repo, arg)

Resolves a parsed range to {base_sha, head_sha}. Three-dot ranges use the merge base.

show(repo, sha, path)

File contents at a commit.

validate_paths(paths)

Validates repo-relative path filters.

validate_repo(repo)

Checks that the repository path is an existing directory.

Types

entry()

@type entry() :: %{
  status: :added | :modified | :deleted | :renamed,
  base_path: String.t() | nil,
  head_path: String.t() | nil
}

range()

@type range() :: {:two_dot | :three_dot, String.t(), String.t()}

Functions

changed_files(repo, base, head, paths)

@spec changed_files(String.t(), String.t(), String.t(), [String.t()]) ::
  {:ok, [entry()]} | {:error, String.t()}

Changed .ex files between two commits, with renames detected.

check_paths(repo, base, head, paths)

@spec check_paths(String.t(), String.t(), String.t(), [String.t()]) ::
  :ok | {:error, String.t()}

Fails unless every path (relative to repo) matches at least one file in the base or the head tree, so a wrong default (subproject, umbrella root) cannot yield an empty success.

parse_range(range)

@spec parse_range(term()) :: {:ok, range()} | {:error, String.t()}

Parses and validates A..B or A...B.

resolve(repo, arg)

@spec resolve(String.t(), range()) ::
  {:ok, {String.t(), String.t()}} | {:error, String.t()}

Resolves a parsed range to {base_sha, head_sha}. Three-dot ranges use the merge base.

show(repo, sha, path)

@spec show(String.t(), String.t(), String.t()) ::
  {:ok, String.t()} | {:error, String.t()}

File contents at a commit.

validate_paths(paths)

@spec validate_paths([term()]) :: {:ok, [String.t()]} | {:error, String.t()}

Validates repo-relative path filters.

validate_repo(repo)

@spec validate_repo(term()) :: {:ok, String.t()} | {:error, String.t()}

Checks that the repository path is an existing directory.