Grader: file-matches

Taxonomy

Property	Value
Determinism	static
Cost	low
Reference	reference-free
Temporal scope	trajectory-level
Score kind	code

Config

graders:
  - type: file-matches
    config:
      path: "**/Program.cs"
      pattern: "static\\s+\\w+\\s+Add\\("

Field	Type	Required	Description
path	string	Yes	Glob pattern to select files in the workspace
pattern	string	Yes	JavaScript regex pattern to match against file content
negate	boolean	No	When true, passes when the pattern does NOT match any file

Negated variant

Use file-not-matches as a shorthand for negate: true:

graders:
  - type: file-not-matches
    config:
      path: "**/Program.cs"
      pattern: "null!"

This is equivalent to type: file-matches with negate: true.

Behavior

1. Finds files matching path in the workspace using glob
2. Validates the regex pattern (fails immediately if invalid)
3. Reads each matching file as UTF-8
4. Tests file content against the regex

Glob patterns match regular files, including dotfiles and files inside dot-directories. Directories, symlinks, and other special entries are not matched.

Passes when the pattern matches at least one readable file. In negated mode, it passes only when every matching file is readable and none matches the pattern, or when no files match. Fails otherwise. If unreadable matching files prevent a conclusive result, both normal and negated modes fail.

Regex flags

Use the (?flags) prefix syntax for inline regex flags:

• (?i)pattern — case-insensitive
• (?m)pattern — multiline (^/$ match line start/end)
• (?s)pattern — dotAll (. matches newlines)

graders:
  - type: file-matches
    config:
      path: "**/*.cs"
      pattern: "(?i)public static void main"

Unreadable files

If a matching file can’t be read (for example, because access is denied or it was removed after matching), it is skipped and noted in the evidence string. Binary files are NOT skipped — readFile("utf-8") returns mojibake for binary content, which simply won’t match most patterns.

If no readable file matches the pattern but at least one candidate was unreadable, the result is indeterminate. Both normal and negated modes fail because presence or absence cannot be proven from the readable files alone.

Evidence examples

✔ Pattern /static\s+Add/ matched in Program.cs
✘ Pattern /static\s+Add/ not found in any file matching '**/Program.cs'
✘ No files matching '**/Program.cs' found
✘ Invalid regex pattern: [bad. Error: Unterminated character class
✔ Pattern /Add/ matched in b.cs (skipped 1 unreadable file: obj/Debug/app.dll)
✘ Indeterminate: Pattern /Add/ did not match any readable file matching '**/*.cs'; 1 unreadable file: obj/Debug/app.dll. Cannot prove presence.