--- title: "Checks" description: "Run Strider's unified formatting, maintainability, and correctness checks." image: "https://strider.gempir.com/og.png" --- > Documentation Index > Fetch the complete documentation index at: https://strider.gempir.com/llms.txt > Use this file to discover all available pages before exploring further. # Checks `strider check` is the single diagnostic command. It combines formatting drift, source-level policy, and package-aware correctness findings in one globally sorted report. It is read-only unless `--fix` or `--fix-unsafe` is requested. Files and parsed source are shared across selected checks, while more expensive program information is prepared only when a selected check needs it. Syntax trees, type information, and control-flow representations are internal scheduling capabilities. They do not create separate commands, configuration sections, or rule namespaces, and a check can change implementation without changing its public code. ## Run checks Run every check at or above the configured severity floor. By default this runs warning and error checks: ```sh strider check [PATH]... ``` Run checks whose effective severity is note or higher: ```sh strider check --minimum-severity note [PATH]... ``` Run exactly a subset of codes: ```sh strider check --only format --only no-init --only invalid-regexp [PATH]... ``` Comma-separated codes are equivalent: ```sh strider check --only format,no-init,invalid-regexp [PATH]... ``` Explicit selection is case-insensitive and retains configured severities, the minimum-severity threshold, and path exclusions. It also lets Strider avoid preparing capabilities the selected checks do not need. Run only checks whose effective severity is warning or higher: ```sh strider check --minimum-severity warning ./... ``` Selection happens first, then per-rule severity overrides, then the minimum threshold (`none < note < warning < error`). `--only` does not bypass the threshold. Checks filtered this way are omitted before Strider plans CST, type, or SSA work. Keep an incremental text-mode session open while editing: ```sh strider check --watch ./... ``` Watch mode reports the initial generation, then emits a fresh complete report when the resulting findings change. It reuses unchanged source snapshots and parsed CSTs, but runs every selected check on each generation so dependency changes are always observed. Baseline generation and pruning, JSON, and HTML are one-shot operations and cannot be combined with `--watch`. ## Apply automatic fixes Apply only automatic fixes explicitly classified as safe: ```sh strider check --fix [PATH]... ``` Include safe, potentially unsafe, and unsafe automatic fixes: ```sh strider check --fix-unsafe [PATH]... ``` The short forms are `-x` and `-u`. The two modes are mutually exclusive and cannot be combined with watch mode, baseline generation, or baseline pruning. The initial automatic set is `format`, `double-negation`, `redundant-switch-break`, and `single-argument-append`. Text reports put a `*` directly after checks with an automatic fix. Green marks safe fixes and purple marks fixes that require `--fix-unsafe`; the same markers appear in the per-check list, and the final issue summary counts both kinds. Fix selection happens only after `--only`, effective severity, path exclusions, source suppressions, and the active baseline have removed ineligible findings. Baselined or suppressed findings are therefore not changed. Strider chooses an explicitly automatic fix at the requested safety level, composes edits per file, and skips every nonidentical overlapping fix with a warning. It then formats affected source unless formatter exclusions or the file's format-ignore directive opt it out, and validates that the result parses. A batch containing safe changes also type-checks against an in-memory overlay before anything is written. The analyzed source is retained as a content snapshot. Every analyzed file is compared after staging and before the first replacement, so a change detected then aborts the whole batch as stale. Each write target is checked again immediately before its replacement. After a successful application, Strider runs the selected checks once more and reports what remains. Exit `0` means the rerun is clean, exit `1` means findings remain, and exit `2` means selection, validation, stale-source detection, or writing failed. All outputs are staged before the first replacement, and each file replacement is atomic. The batch is not a filesystem transaction: if a later rename fails or a concurrent edit is detected after commit starts, an earlier replacement can remain committed. Permission bits are preserved; ownership, ACLs, and extended attributes depend on the host filesystem. A directly named source symlink is kept and guarded against retargeting while its captured target is updated. Safe means the transformation is designed to preserve Go program semantics. Parsing and type-checking provide strong guards against invalid output, but they cannot prove identical observable behavior under every toolchain, build tag, platform, or environment. Review unsafe fixes according to the code and deployment contexts that matter to the project. ## Discover checks Inspect the checks admitted by the effective severity floor: ```sh strider check --list-checks strider check --minimum-severity none --list-checks strider check --explain invalid-regexp ``` The generated catalog statistics report the current inventory. Individual check pages are grouped by purpose in the documentation sidebar. ## Configure checks Every check code accepts `severity` and path `excludes` directly under the version-1 `[checks.]` namespace: ```toml version = 1 [check] minimum-severity = "warning" [checks.format] severity = "note" [checks.file-length-limit] severity = "error" max-lines = 800 excludes = ["testdata/golden/**"] [checks.unclosed-http-response-body] severity = "error" [checks.no-init] severity = "none" ``` The tool-wide minimum severity, exclusions, and default baseline live under `[check]`. Formatter layout and formatter-only exclusions remain under `[formatter]`. See [Configuration](/configuration/#checks) for the complete contract. ## Formatting findings Formatting participates as code `format`. An unformatted file produces a normal note at the start of the file, with a green `*` marking its safe automatic fix: ```text format*: file is not formatted ┌─ main.go:1:1 │ 1 │ package main 2 │ ``` Without a fix flag, `check` never writes the formatted candidate. Use `strider fmt`, or `strider fmt --diff` to inspect the change. `check --fix` applies the same validated candidate. Formatting findings are not captured by baselines. ## Reports Text is the default human-readable report format: 
no-init: replace init with explicit initialization
   ┌─ main.go:12:6
   │
11 │
12 │ func init() {
13 │     configure()

no-init  1
1 issue: 1 note
Use JSON for integrations or HTML for a self-contained artifact: ```sh strider check --format json ./... strider check --format html ./... > check-report.html ``` Each JSON diagnostic includes `code`, `message`, `severity`, `file`, `start`, and `end`; diagnostics may also carry notes and suggested remedies. HTML reports include severity totals, search, filters, and source context without external assets or timestamps. Source: https://strider.gempir.com/checks/index.mdx