fallow_api/runtime/
feature_flags.rs

1use std::path::Path;
2use std::time::Instant;
3
4use fallow_engine::{AnalysisSession, ProjectConfig};
5use fallow_output::{
6    CHECK_SCHEMA_VERSION, FeatureFlagsOutputInput, build_feature_flags_output, feature_flags_meta,
7    relative_to_diff_path,
8};
9use fallow_types::output_format::OutputFormat;
10use fallow_types::results::FeatureFlag;
11
12use crate::{
13    FeatureFlagsOptions, FeatureFlagsProgrammaticOutput, ProgrammaticError,
14    analysis_context::{
15        ProgrammaticAnalysisContext, changed_files_for_run, resolve_programmatic_analysis_context,
16    },
17};
18
19use super::{ProgrammaticResult, root_envelope_mode};
20
21/// Run feature-flag analysis and return typed API output before JSON.
22///
23/// # Errors
24///
25/// Returns a structured programmatic error for invalid options, config load
26/// failures, git changed-file failures, or analysis failures.
27pub fn run_feature_flags(
28    options: &FeatureFlagsOptions,
29) -> ProgrammaticResult<FeatureFlagsProgrammaticOutput> {
30    let resolved = resolve_programmatic_analysis_context(&options.analysis)?;
31    resolved.install(|| run_feature_flags_inner(options, &resolved))
32}
33
34fn run_feature_flags_inner(
35    options: &FeatureFlagsOptions,
36    resolved: &ProgrammaticAnalysisContext,
37) -> ProgrammaticResult<FeatureFlagsProgrammaticOutput> {
38    let start = Instant::now();
39    let session = load_feature_flags_session(resolved)?;
40    let analysis = fallow_engine::analyze_feature_flags(session.config());
41    if analysis.files_scanned == 0 {
42        return Err(ProgrammaticError::new("no files discovered", 2)
43            .with_code("FALLOW_NO_FILES_DISCOVERED")
44            .with_context("feature-flags"));
45    }
46
47    let mut flags = analysis.flags;
48    apply_feature_flags_scope(&mut flags, resolved, session.root())?;
49    sort_and_limit_feature_flags(&mut flags, options.top);
50
51    let output = build_feature_flags_output(FeatureFlagsOutputInput {
52        schema_version: CHECK_SCHEMA_VERSION,
53        version: env!("CARGO_PKG_VERSION").to_string(),
54        elapsed: start.elapsed(),
55        flags: &flags,
56        root: session.root(),
57        meta: resolved.explain_enabled().then(feature_flags_meta),
58    });
59
60    Ok(FeatureFlagsProgrammaticOutput {
61        output,
62        envelope_mode: root_envelope_mode(),
63        telemetry_analysis_run_id: None,
64    })
65}
66
67fn load_feature_flags_session(
68    resolved: &ProgrammaticAnalysisContext,
69) -> ProgrammaticResult<AnalysisSession> {
70    let project_config =
71        fallow_engine::config_for_project(&resolved.root, resolved.config_path.as_deref())
72            .map_err(|err| {
73                ProgrammaticError::new(format!("failed to load config: {err}"), 2)
74                    .with_code("FALLOW_CONFIG_LOAD_FAILED")
75                    .with_context("analysis.configPath")
76            })?;
77    Ok(AnalysisSession::from_config(
78        configure_project_for_feature_flags(project_config, resolved),
79    ))
80}
81
82fn configure_project_for_feature_flags(
83    mut project_config: ProjectConfig,
84    resolved: &ProgrammaticAnalysisContext,
85) -> ProjectConfig {
86    project_config.config.output = OutputFormat::Json;
87    project_config.config.no_cache = resolved.no_cache;
88    project_config.config.threads = resolved.threads;
89    project_config.config.production = resolved
90        .production_override
91        .unwrap_or(project_config.config.production);
92    project_config
93}
94
95fn apply_feature_flags_scope(
96    flags: &mut Vec<FeatureFlag>,
97    resolved: &ProgrammaticAnalysisContext,
98    root: &Path,
99) -> ProgrammaticResult<()> {
100    if let Some(workspace_roots) = resolved.workspace_roots.as_ref() {
101        flags.retain(|flag| {
102            workspace_roots
103                .iter()
104                .any(|root| flag.path.starts_with(root))
105        });
106    }
107    if let Some(changed_files) = changed_files_for_run(resolved)? {
108        flags.retain(|flag| changed_files.contains(&flag.path));
109    }
110    if let Some(diff) = resolved.diff.as_ref() {
111        flags.retain(|flag| {
112            relative_to_diff_path(&flag.path, root).is_none_or(|rel| diff.touches_file(&rel))
113        });
114    }
115    Ok(())
116}
117
118fn sort_and_limit_feature_flags(flags: &mut Vec<FeatureFlag>, top: Option<usize>) {
119    flags.sort_by(|a, b| {
120        a.path
121            .cmp(&b.path)
122            .then(a.line.cmp(&b.line))
123            .then(a.flag_name.cmp(&b.flag_name))
124    });
125
126    if let Some(top) = top {
127        flags.truncate(top);
128    }
129}
fallow_api/runtime/feature_flags.rs

fallow_api/runtime/
feature_flags.rs
