zeph_tools/
diagnostics.rs

1// SPDX-FileCopyrightText: 2026 Andrei G <bug-ops>
2// SPDX-License-Identifier: MIT OR Apache-2.0
3
4use std::path::{Path, PathBuf};
5
6use schemars::JsonSchema;
7use serde::Deserialize;
8
9use crate::executor::{ToolCall, ToolError, ToolExecutor, ToolOutput, deserialize_params};
10use crate::registry::{InvocationHint, ToolDef};
11
12/// Cargo diagnostics level.
13#[derive(Debug, Default, Deserialize, JsonSchema, PartialEq, Eq)]
14#[serde(rename_all = "snake_case")]
15pub enum DiagnosticsLevel {
16    /// Run `cargo check`
17    #[default]
18    Check,
19    /// Run `cargo clippy`
20    Clippy,
21}
22
23#[derive(Debug, Deserialize, JsonSchema)]
24struct DiagnosticsParams {
25    /// Workspace path (defaults to current directory)
26    path: Option<String>,
27    /// Diagnostics level: check or clippy
28    #[serde(default)]
29    level: DiagnosticsLevel,
30}
31
32/// Runs `cargo check` or `cargo clippy` and returns structured diagnostics.
33#[derive(Debug)]
34pub struct DiagnosticsExecutor {
35    allowed_paths: Vec<PathBuf>,
36    /// Maximum number of diagnostics to return (default: 50)
37    max_diagnostics: usize,
38}
39
40impl DiagnosticsExecutor {
41    #[must_use]
42    pub fn new(allowed_paths: Vec<PathBuf>) -> Self {
43        let paths = if allowed_paths.is_empty() {
44            vec![std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."))]
45        } else {
46            allowed_paths
47        };
48        Self {
49            allowed_paths: paths
50                .into_iter()
51                .map(|p| p.canonicalize().unwrap_or(p))
52                .collect(),
53            max_diagnostics: 50,
54        }
55    }
56
57    #[must_use]
58    pub fn with_max_diagnostics(mut self, max: usize) -> Self {
59        self.max_diagnostics = max;
60        self
61    }
62
63    fn validate_path(&self, path: &Path) -> Result<PathBuf, ToolError> {
64        let resolved = if path.is_absolute() {
65            path.to_path_buf()
66        } else {
67            std::env::current_dir()
68                .unwrap_or_else(|_| PathBuf::from("."))
69                .join(path)
70        };
71        let canonical = resolved.canonicalize().map_err(|e| {
72            ToolError::Execution(std::io::Error::new(
73                std::io::ErrorKind::NotFound,
74                format!("path not found: {}: {e}", resolved.display()),
75            ))
76        })?;
77        if !self.allowed_paths.iter().any(|a| canonical.starts_with(a)) {
78            return Err(ToolError::SandboxViolation {
79                path: canonical.display().to_string(),
80            });
81        }
82        Ok(canonical)
83    }
84}
85
86impl ToolExecutor for DiagnosticsExecutor {
87    async fn execute(&self, _response: &str) -> Result<Option<ToolOutput>, ToolError> {
88        Ok(None)
89    }
90
91    async fn execute_tool_call(&self, call: &ToolCall) -> Result<Option<ToolOutput>, ToolError> {
92        if call.tool_id != "diagnostics" {
93            return Ok(None);
94        }
95        let p: DiagnosticsParams = deserialize_params(&call.params)?;
96        let work_dir = if let Some(path) = &p.path {
97            self.validate_path(Path::new(path))?
98        } else {
99            let cwd = std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."));
100            self.validate_path(&cwd)?
101        };
102
103        let subcmd = match p.level {
104            DiagnosticsLevel::Check => "check",
105            DiagnosticsLevel::Clippy => "clippy",
106        };
107
108        let cargo = which_cargo()?;
109
110        let output = tokio::process::Command::new(&cargo)
111            .arg(subcmd)
112            .arg("--message-format=json")
113            .current_dir(&work_dir)
114            .output()
115            .await
116            .map_err(|e| {
117                ToolError::Execution(std::io::Error::new(
118                    std::io::ErrorKind::NotFound,
119                    format!("failed to run cargo: {e}"),
120                ))
121            })?;
122
123        let stdout = String::from_utf8_lossy(&output.stdout);
124        let diagnostics = parse_cargo_json(&stdout, self.max_diagnostics);
125
126        let summary = if diagnostics.is_empty() {
127            "No diagnostics".to_owned()
128        } else {
129            diagnostics.join("\n")
130        };
131
132        Ok(Some(ToolOutput {
133            tool_name: "diagnostics".to_owned(),
134            summary,
135            blocks_executed: 1,
136            filter_stats: None,
137            diff: None,
138            streamed: false,
139            terminal_id: None,
140            locations: None,
141            raw_response: None,
142            claim_source: Some(crate::executor::ClaimSource::Diagnostics),
143        }))
144    }
145
146    fn tool_definitions(&self) -> Vec<ToolDef> {
147        vec![ToolDef {
148            id: "diagnostics".into(),
149            description: "Run cargo check or cargo clippy on a Rust workspace and return compiler diagnostics.\n\nParameters: path (string, optional) - workspace directory (default: cwd); level (string, optional) - \"check\" or \"clippy\" (default: \"check\")\nReturns: structured diagnostics with file paths, line numbers, severity, and messages; capped at 50 results\nErrors: SandboxViolation if path outside allowed dirs; Execution if cargo is not found\nExample: {\"path\": \".\", \"level\": \"clippy\"}".into(),
150            schema: schemars::schema_for!(DiagnosticsParams),
151            invocation: InvocationHint::ToolCall,
152        }]
153    }
154}
155
156/// Returns the path to the `cargo` binary, failing gracefully if not found.
157///
158/// Reads the `CARGO` environment variable (set by rustup/cargo during builds) or
159/// falls back to a PATH search. The process environment is assumed trusted — this
160/// function runs in the same process as the agent, not in an untrusted context.
161/// Canonicalization is applied as defence-in-depth to resolve any symlinks in the path.
162fn which_cargo() -> Result<PathBuf, ToolError> {
163    // Check CARGO env var first (set by rustup/cargo itself)
164    if let Ok(cargo) = std::env::var("CARGO") {
165        let p = PathBuf::from(&cargo);
166        if p.is_file() {
167            return Ok(p.canonicalize().unwrap_or(p));
168        }
169    }
170    // Fall back to PATH lookup
171    for dir in std::env::var("PATH").unwrap_or_default().split(':') {
172        let candidate = PathBuf::from(dir).join("cargo");
173        if candidate.is_file() {
174            return Ok(candidate.canonicalize().unwrap_or(candidate));
175        }
176    }
177    Err(ToolError::Execution(std::io::Error::new(
178        std::io::ErrorKind::NotFound,
179        "cargo not found in PATH",
180    )))
181}
182
183/// Parses cargo JSON output lines and extracts human-readable diagnostics.
184///
185/// Each JSON line from `--message-format=json` that represents a `compiler-message`
186/// with a span is formatted as `file:line:col: level: message`.
187pub(crate) fn parse_cargo_json(output: &str, max: usize) -> Vec<String> {
188    let mut results = Vec::new();
189    for line in output.lines() {
190        if results.len() >= max {
191            break;
192        }
193        let Ok(val) = serde_json::from_str::<serde_json::Value>(line) else {
194            continue;
195        };
196        if val.get("reason").and_then(|r| r.as_str()) != Some("compiler-message") {
197            continue;
198        }
199        let Some(msg) = val.get("message") else {
200            continue;
201        };
202        let level = msg
203            .get("level")
204            .and_then(|l| l.as_str())
205            .unwrap_or("unknown");
206        let text = msg
207            .get("message")
208            .and_then(|m| m.as_str())
209            .unwrap_or("")
210            .trim();
211        if text.is_empty() {
212            continue;
213        }
214
215        // Use the primary span if available for location info
216        let spans = msg
217            .get("spans")
218            .and_then(serde_json::Value::as_array)
219            .map_or(&[] as &[_], Vec::as_slice);
220
221        let primary = spans.iter().find(|s| {
222            s.get("is_primary")
223                .and_then(serde_json::Value::as_bool)
224                .unwrap_or(false)
225        });
226
227        if let Some(span) = primary {
228            let file = span
229                .get("file_name")
230                .and_then(|f| f.as_str())
231                .unwrap_or("?");
232            let line = span
233                .get("line_start")
234                .and_then(serde_json::Value::as_u64)
235                .unwrap_or(0);
236            let col = span
237                .get("column_start")
238                .and_then(serde_json::Value::as_u64)
239                .unwrap_or(0);
240            results.push(format!("{file}:{line}:{col}: {level}: {text}"));
241        } else {
242            results.push(format!("{level}: {text}"));
243        }
244    }
245    results
246}
247
248#[cfg(test)]
249mod tests {
250    use super::*;
251
252    fn make_params(
253        pairs: &[(&str, serde_json::Value)],
254    ) -> serde_json::Map<String, serde_json::Value> {
255        pairs
256            .iter()
257            .map(|(k, v)| ((*k).to_owned(), v.clone()))
258            .collect()
259    }
260
261    // --- parse_cargo_json unit tests ---
262
263    #[test]
264    fn parse_cargo_json_empty_input() {
265        let result = parse_cargo_json("", 50);
266        assert!(result.is_empty());
267    }
268
269    #[test]
270    fn parse_cargo_json_non_compiler_message_ignored() {
271        let line = r#"{"reason":"build-script-executed","package_id":"foo"}"#;
272        let result = parse_cargo_json(line, 50);
273        assert!(result.is_empty());
274    }
275
276    #[test]
277    fn parse_cargo_json_compiler_message_with_span() {
278        let line = r#"{"reason":"compiler-message","message":{"level":"error","message":"cannot find value `foo` in this scope","spans":[{"file_name":"src/main.rs","line_start":10,"column_start":5,"is_primary":true}]}}"#;
279        let result = parse_cargo_json(line, 50);
280        assert_eq!(result.len(), 1);
281        assert!(result[0].contains("src/main.rs"));
282        assert!(result[0].contains("10"));
283        assert!(result[0].contains("error"));
284        assert!(result[0].contains("cannot find value"));
285    }
286
287    #[test]
288    fn parse_cargo_json_warning_with_span() {
289        let line = r#"{"reason":"compiler-message","message":{"level":"warning","message":"unused variable: `x`","spans":[{"file_name":"src/lib.rs","line_start":3,"column_start":9,"is_primary":true}]}}"#;
290        let result = parse_cargo_json(line, 50);
291        assert_eq!(result.len(), 1);
292        assert!(result[0].starts_with("src/lib.rs:3:9: warning:"));
293    }
294
295    #[test]
296    fn parse_cargo_json_no_primary_span_uses_message_only() {
297        let line = r#"{"reason":"compiler-message","message":{"level":"error","message":"aborting due to previous error","spans":[]}}"#;
298        let result = parse_cargo_json(line, 50);
299        assert_eq!(result.len(), 1);
300        assert_eq!(result[0], "error: aborting due to previous error");
301    }
302
303    #[test]
304    fn parse_cargo_json_max_cap_respected() {
305        let single = r#"{"reason":"compiler-message","message":{"level":"warning","message":"unused","spans":[]}}"#;
306        let input: String = (0..20).map(|_| single).collect::<Vec<_>>().join("\n");
307        let result = parse_cargo_json(&input, 5);
308        assert_eq!(result.len(), 5);
309    }
310
311    #[test]
312    fn parse_cargo_json_empty_message_skipped() {
313        let line = r#"{"reason":"compiler-message","message":{"level":"note","message":"   ","spans":[]}}"#;
314        let result = parse_cargo_json(line, 50);
315        assert!(result.is_empty());
316    }
317
318    #[test]
319    fn parse_cargo_json_non_primary_span_skipped_for_location() {
320        let line = r#"{"reason":"compiler-message","message":{"level":"warning","message":"some warning","spans":[{"file_name":"src/foo.rs","line_start":1,"column_start":1,"is_primary":false}]}}"#;
321        // No primary span → fall back to message-only format
322        let result = parse_cargo_json(line, 50);
323        assert_eq!(result.len(), 1);
324        assert_eq!(result[0], "warning: some warning");
325    }
326
327    #[test]
328    fn parse_cargo_json_invalid_json_line_skipped() {
329        let input = "not json\n{\"reason\":\"build-script-executed\"}";
330        let result = parse_cargo_json(input, 50);
331        assert!(result.is_empty());
332    }
333
334    // --- sandbox tests ---
335
336    #[tokio::test]
337    async fn diagnostics_sandbox_violation() {
338        let dir = tempfile::tempdir().unwrap();
339        let exec = DiagnosticsExecutor::new(vec![dir.path().to_path_buf()]);
340
341        let call = ToolCall {
342            tool_id: "diagnostics".to_owned(),
343            params: make_params(&[("path", serde_json::json!("/etc"))]),
344        };
345        let result = exec.execute_tool_call(&call).await;
346        assert!(result.is_err());
347    }
348
349    #[tokio::test]
350    async fn diagnostics_unknown_tool_returns_none() {
351        let exec = DiagnosticsExecutor::new(vec![]);
352        let call = ToolCall {
353            tool_id: "other".to_owned(),
354            params: serde_json::Map::new(),
355        };
356        let result = exec.execute_tool_call(&call).await.unwrap();
357        assert!(result.is_none());
358    }
359
360    #[test]
361    fn diagnostics_tool_definition() {
362        let exec = DiagnosticsExecutor::new(vec![]);
363        let defs = exec.tool_definitions();
364        assert_eq!(defs.len(), 1);
365        assert_eq!(defs[0].id, "diagnostics");
366        assert_eq!(defs[0].invocation, InvocationHint::ToolCall);
367    }
368
369    #[test]
370    fn diagnostics_level_default_is_check() {
371        assert_eq!(DiagnosticsLevel::default(), DiagnosticsLevel::Check);
372    }
373
374    #[test]
375    fn diagnostics_level_deserialize_check() {
376        let p: DiagnosticsParams = serde_json::from_str(r#"{"level":"check"}"#).unwrap();
377        assert_eq!(p.level, DiagnosticsLevel::Check);
378    }
379
380    #[test]
381    fn diagnostics_level_deserialize_clippy() {
382        let p: DiagnosticsParams = serde_json::from_str(r#"{"level":"clippy"}"#).unwrap();
383        assert_eq!(p.level, DiagnosticsLevel::Clippy);
384    }
385
386    #[test]
387    fn diagnostics_params_path_optional() {
388        let p: DiagnosticsParams = serde_json::from_str(r"{}").unwrap();
389        assert!(p.path.is_none());
390        assert_eq!(p.level, DiagnosticsLevel::Check);
391    }
392
393    // CR-14: verify that level=clippy maps to "clippy" subcommand string
394    #[test]
395    fn diagnostics_clippy_subcmd_string() {
396        let subcmd = match DiagnosticsLevel::Clippy {
397            DiagnosticsLevel::Check => "check",
398            DiagnosticsLevel::Clippy => "clippy",
399        };
400        assert_eq!(subcmd, "clippy");
401    }
402
403    #[test]
404    fn diagnostics_check_subcmd_string() {
405        let subcmd = match DiagnosticsLevel::Check {
406            DiagnosticsLevel::Check => "check",
407            DiagnosticsLevel::Clippy => "clippy",
408        };
409        assert_eq!(subcmd, "check");
410    }
411}
zeph_tools/diagnostics.rs

zeph_tools/
diagnostics.rs
