mitts 0.3.7

Rust-first build and package tooling with a shared artifact cache
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
/*
 * Mitts Build — Rust-first build and package tooling with shared artifact cache
 * Copyright (c) 2026 Alexander Panasenko
 *
 * Contact: alex@prod.codes
 * Author: https://prod.codes/about/
 * Project: https://github.com/alex09x/mitts
 * SPDX-License-Identifier: MIT OR Apache-2.0
 */

use super::features::{resolve_package_features_with_resolver, PackageFeatureContext};
use super::lockfile::{CargoLock, CargoLockPackage};
use super::manifest::CargoToml;
use super::package_selection::select_transitive_packages;
use super::types::{EffectivePlanExplanation, RustBuildOptions};
use crate::adapter::RustAdapter;
use anyhow::{Context, Result};
use std::collections::HashMap;
use std::path::{Path, PathBuf};

/// Derives the effective build plan and compilation units natively without invoking Cargo.
pub(crate) fn explain_plan(opt: &RustBuildOptions) -> Result<EffectivePlanExplanation> {
    // `mitts explain` reaches the planner without the builder: the toolchain probe cache
    // has to be pointed at the cache root here too.
    super::toolchain_probes::set_cache_root(&crate::core::cache_root::resolve(
        opt.cache_dir.as_deref(),
    ));
    let manifest_scope = super::manifest_snapshot::scope();
    let t0 = std::time::Instant::now();
    let s0 = super::compiler_resolve::rustc_subproc_stats();
    let manifest_path = RustAdapter::resolve_manifest(opt)?;
    let target_dir = RustAdapter::resolve_target_dir(&manifest_path, opt)?;
    let project_dir = manifest_path.parent().unwrap_or(Path::new("."));
    let ws_root = super::compiler_resolve::find_workspace_root(&manifest_path);
    let toolchain = RustAdapter::detect_toolchain()?;
    let t_toolchain = std::time::Instant::now();
    let s_toolchain = super::compiler_resolve::rustc_subproc_stats();

    let root_toml = CargoToml::from_file(&manifest_path)
        .with_context(|| format!("Failed to parse root manifest at {manifest_path:?}"))?;
    let cfg_dir = super::cargo_config::resolve_config_start_dir_with_opt(
        project_dir,
        opt.start_dir.as_deref(),
    );
    let explicit_target =
        super::key_flags::resolve_explicit_target_from_args_and_dir(&opt.extra_args, &cfg_dir);
    let _ = super::cargo_config::load_cargo_config_rustflags(&cfg_dir, explicit_target.as_deref())?;
    let _ = super::profile::resolve_unit_profile(
        &manifest_path,
        "",
        true,
        false,
        opt.release,
        Some(ws_root.as_path()),
    )?;

    let members = root_toml.discover_workspace_members(project_dir)?;
    let mut workspace_manifests: HashMap<String, (PathBuf, CargoToml)> = HashMap::new();
    for (name, member_dir) in &members {
        let m_path = member_dir.join("Cargo.toml");
        let toml = CargoToml::from_file(&m_path).with_context(|| {
            format!("Failed to parse workspace member manifest at {:?}", m_path)
        })?;
        workspace_manifests.insert(name.clone(), (member_dir.clone(), toml));
    }

    let mut path_dependencies: HashMap<String, (PathBuf, CargoToml)> = HashMap::new();
    let mut scan_deps = |base_dir: &Path,
                         deps: &HashMap<String, super::manifest::TomlDependency>|
     -> Result<()> {
        for (dep_name, dep_val) in deps {
            if let super::manifest::TomlDependency::Detailed(ref d) = dep_val {
                if let Some(ref rel_p) = d.path {
                    let dep_dir = base_dir.join(rel_p);
                    let dep_manifest = dep_dir.join("Cargo.toml");
                    let dep_toml = CargoToml::from_file(&dep_manifest)
                        .with_context(|| format!("failed to read `{}`", dep_manifest.display()))?;
                    let name = dep_toml
                        .package
                        .as_ref()
                        .map(|p| p.name.clone())
                        .unwrap_or_else(|| dep_name.clone());
                    path_dependencies.insert(name, (dep_dir, dep_toml));
                }
            }
        }
        Ok(())
    };

    if let Some(ref ws) = root_toml.workspace {
        scan_deps(project_dir, &ws.dependencies)?;
    }
    let tomls_to_scan: Vec<(&Path, &CargoToml)> = std::iter::once((project_dir, &root_toml))
        .chain(workspace_manifests.values().map(|(p, t)| (p.as_path(), t)))
        .collect();
    // Dev-dependencies count too: Cargo.lock lists a path dev-dependency like any
    // other path package, so the planner must know where it lives even for a build
    // that never compiles it.
    for (base, toml) in tomls_to_scan {
        scan_deps(base, &toml.dependencies)?;
        scan_deps(base, &toml.build_dependencies)?;
        scan_deps(base, &toml.dev_dependencies)?;
        for t in toml.target.values() {
            scan_deps(base, &t.dependencies)?;
            scan_deps(base, &t.build_dependencies)?;
            scan_deps(base, &t.dev_dependencies)?;
        }
    }

    // `[patch.*] foo = { path = "…" }` packages are path packages too.
    for table in root_toml.patch.values() {
        scan_deps(project_dir, table)?;
    }

    if root_toml.workspace.is_some() {
        let canon_proj = project_dir
            .canonicalize()
            .unwrap_or_else(|_| project_dir.to_path_buf());
        for (name, (path, toml)) in &path_dependencies {
            let canon_path = path.canonicalize().unwrap_or_else(|_| path.to_path_buf());
            if canon_path.starts_with(&canon_proj) {
                workspace_manifests
                    .entry(name.clone())
                    .or_insert_with(|| (path.clone(), toml.clone()));
            }
        }
    }

    let t_workspace = std::time::Instant::now();
    let lock_path = project_dir
        .ancestors()
        .map(|p| p.join("Cargo.lock"))
        .find(|p| p.is_file());
    let mut lockfile = match lock_path {
        Some(ref lp) => CargoLock::from_file(lp)?,
        None => CargoLock::resolve_or_sync(&manifest_path, false, opt.cache_dir.as_deref())?,
    };

    // Ensure all path dependencies and workspace packages exist in the lockfile
    let mut sorted_path_deps: Vec<_> = path_dependencies.iter().collect();
    sorted_path_deps.sort_by_key(|(name, _)| *name);
    for (name, (_path, dep_toml)) in sorted_path_deps {
        let ver = dep_toml
            .package
            .as_ref()
            .and_then(|p| p.version.clone())
            .unwrap_or_else(|| "0.0.0".to_string());
        if lockfile
            .packages
            .iter()
            .any(|p| &p.name == name && p.source.is_none() && p.version == ver)
        {
            continue;
        }
        let local_count = lockfile
            .packages
            .iter()
            .filter(|p| &p.name == name && p.source.is_none())
            .count();
        if local_count == 1 {
            if let Some(existing) = lockfile
                .packages
                .iter_mut()
                .find(|p| &p.name == name && p.source.is_none())
            {
                existing.version = ver;
            }
        } else {
            let mut deps: Vec<String> = dep_toml.dependencies.keys().cloned().collect();
            deps.sort();
            lockfile.packages.push(CargoLockPackage {
                name: name.clone(),
                version: ver,
                source: None,
                checksum: None,
                dependencies: deps,
            });
        }
    }

    let mut sorted_ws_manifests: Vec<_> = workspace_manifests.iter().collect();
    sorted_ws_manifests.sort_by_key(|(name, _)| *name);
    for (name, (_dir, manifest)) in sorted_ws_manifests {
        let ver = manifest
            .package
            .as_ref()
            .and_then(|p| p.version.clone())
            .unwrap_or_else(|| "0.0.0".to_string());
        if lockfile
            .packages
            .iter()
            .any(|p| &p.name == name && p.source.is_none() && p.version == ver)
        {
            continue;
        }
        let local_count = lockfile
            .packages
            .iter()
            .filter(|p| &p.name == name && p.source.is_none())
            .count();
        if local_count == 1 {
            if let Some(existing) = lockfile
                .packages
                .iter_mut()
                .find(|p| &p.name == name && p.source.is_none())
            {
                existing.version = ver;
            }
        } else {
            let mut deps = Vec::new();
            let mut all_deps: Vec<(&String, &super::manifest::TomlDependency)> =
                manifest.dependencies.iter().collect();
            for t in manifest.target.values() {
                all_deps.extend(&t.dependencies);
            }
            for (dep_name, dep_val) in all_deps {
                let real_name = match dep_val {
                    super::manifest::TomlDependency::Detailed(d) => {
                        d.package_name.as_deref().unwrap_or(dep_name.as_str())
                    }
                    _ => dep_name.as_str(),
                };
                if let Some(target) = lockfile.packages.iter().find(|p| p.name == real_name) {
                    deps.push(target.name.clone());
                } else if path_dependencies.contains_key(real_name) {
                    deps.push(real_name.to_string());
                }
            }
            deps.sort();
            deps.dedup();
            lockfile.packages.push(CargoLockPackage {
                name: name.clone(),
                version: ver,
                source: None,
                checksum: None,
                dependencies: deps,
            });
        }
    }
    let t_lockfile = std::time::Instant::now();
    let s_lockfile = super::compiler_resolve::rustc_subproc_stats();

    // Select root packages and collect all reachable transitive dependencies
    let selected_packages = select_transitive_packages(
        &lockfile,
        &workspace_manifests,
        &root_toml,
        project_dir,
        opt,
    )?;
    let t_select = std::time::Instant::now();
    let s_select = super::compiler_resolve::rustc_subproc_stats();

    let resolved_packages = super::source_lookup::resolve_selected_package_manifests(
        &selected_packages,
        &workspace_manifests,
        &path_dependencies,
        project_dir,
        opt.cache_dir.as_deref(),
        lockfile.version,
    )?;
    let t_resolve = std::time::Instant::now();
    let s_resolve = super::compiler_resolve::rustc_subproc_stats();

    // Determine root packages being targeted by the build
    let target_pkg = opt.package.as_deref();
    let has_all_ws = opt
        .extra_args
        .iter()
        .any(|a| a == "--workspace" || a == "--all");
    let is_virtual_workspace = root_toml.workspace.is_some() && root_toml.package.is_none();
    let default_members = root_toml
        .workspace
        .as_ref()
        .map(|w| &w.default_members)
        .filter(|dm| !dm.is_empty());

    let is_selected_ws_member = |pkg_name: &str| -> bool {
        if let Some(dm) = default_members {
            dm.iter().any(|member_pat| {
                let clean_pat = member_pat.trim_start_matches("./").trim_end_matches('/');
                let member_dir = if clean_pat == "." || clean_pat.is_empty() {
                    project_dir.to_path_buf()
                } else {
                    project_dir.join(clean_pat)
                };
                workspace_manifests.get(pkg_name).is_some_and(|(dir, _)| {
                    dir == &member_dir || (clean_pat == "." && dir == project_dir)
                })
            })
        } else {
            workspace_manifests.contains_key(pkg_name)
        }
    };

    if let Some(dm) = default_members {
        if !workspace_manifests.keys().any(|k| is_selected_ws_member(k)) {
            anyhow::bail!("No workspace members matched default-members: {:?}", dm);
        }
    }

    let is_primary_pkg = |name: &str| -> bool {
        if opt.exclude.iter().any(|ex| ex == name) {
            return false;
        }
        target_pkg.map_or_else(
            || {
                (has_all_ws && workspace_manifests.contains_key(name))
                    || ((is_virtual_workspace || default_members.is_some())
                        && is_selected_ws_member(name))
                    || root_toml.package.as_ref().is_some_and(|p| p.name == name)
            },
            |target| name == target,
        )
    };

    // Resolve unified compile-time features across all packages
    let feature_inputs: Vec<PackageFeatureContext> = resolved_packages
        .iter()
        .map(|(pkg, is_ws, _, toml)| PackageFeatureContext {
            name: pkg.name.as_str(),
            version: pkg.version.as_str(),
            source: pkg.source.as_deref(),
            is_workspace: *is_ws,
            is_root: is_primary_pkg(&pkg.name),
            toml,
            dependencies: &pkg.dependencies,
        })
        .collect();
    let ws_resolver = CargoToml::effective_resolver_for_manifest(&manifest_path, &root_toml)?;
    let package_features =
        resolve_package_features_with_resolver(&feature_inputs, opt, Some(&ws_resolver))?;
    let t_features = std::time::Instant::now();
    let s_features = super::compiler_resolve::rustc_subproc_stats();

    // Pass 1: Build compilation units with assigned features (Resolver 2 decoupled host/target)
    let mut units = super::planner_units::build_planned_units(
        &resolved_packages,
        &path_dependencies,
        &package_features,
        opt,
        is_primary_pkg,
        Some(ws_root.as_path()),
    );
    let t_units = std::time::Instant::now();
    let s_units = super::compiler_resolve::rustc_subproc_stats();

    // Pass 2: Resolve exact unit dependencies matching library or proc-macro targets
    let explicit_target = crate::adapter::rust::key_flags::resolve_explicit_target(opt);
    let start_dir = opt.start_dir.as_deref().unwrap_or(project_dir);
    super::planner_deps::resolve_unit_dependencies_with_manifests(
        &mut units,
        &selected_packages,
        &resolved_packages,
        explicit_target.as_deref(),
        start_dir,
    )?;

    // Prune compilation units not reachable from active root targets
    for u in &mut units {
        u.is_primary = is_primary_pkg(&u.package_name);
    }

    super::planner_units::prune_plan_root_units(&mut units, opt, has_all_ws);
    let t_deps = std::time::Instant::now();
    let s_deps = super::compiler_resolve::rustc_subproc_stats();

    if std::env::var_os("MITTS_TIMINGS").is_some() {
        eprintln!(
            "[mitts::timings] explain_plan: toolchain={:.2}ms(rustc={}/{:.2}ms) workspace={:.2}ms lockfile={:.2}ms select={:.2}ms(rustc={}/{:.2}ms) resolve_manifests={:.2}ms features={:.2}ms(rustc={}/{:.2}ms) units={:.2}ms deps={:.2}ms(rustc={}/{:.2}ms) total={:.2}ms(rustc_total={}/{:.2}ms) (pkgs={}, units={})",
            t_toolchain.duration_since(t0).as_secs_f64() * 1000.0,
            s_toolchain.0 - s0.0,
            s_toolchain.1 - s0.1,
            t_workspace.duration_since(t_toolchain).as_secs_f64() * 1000.0,
            t_lockfile.duration_since(t_workspace).as_secs_f64() * 1000.0,
            t_select.duration_since(t_lockfile).as_secs_f64() * 1000.0,
            s_select.0 - s_lockfile.0,
            s_select.1 - s_lockfile.1,
            t_resolve.duration_since(t_select).as_secs_f64() * 1000.0,
            t_features.duration_since(t_resolve).as_secs_f64() * 1000.0,
            s_features.0 - s_resolve.0,
            s_features.1 - s_resolve.1,
            t_units.duration_since(t_features).as_secs_f64() * 1000.0,
            t_deps.duration_since(t_units).as_secs_f64() * 1000.0,
            s_deps.0 - s_units.0,
            s_deps.1 - s_units.1,
            t_deps.duration_since(t0).as_secs_f64() * 1000.0,
            s_deps.0 - s0.0,
            s_deps.1 - s0.1,
            resolved_packages.len(),
            units.len(),
        );
    }

    let profile = if opt.release { "release" } else { "debug" }.to_string();
    manifest_scope.snapshot().verify_fresh()?;

    Ok(EffectivePlanExplanation {
        manifest_path,
        target_directory: target_dir,
        profile,
        toolchain,
        units,
        manifest_snapshot: manifest_scope.snapshot(),
    })
}