monochromatic-git-policy-cli 0.5.31

//! The mechanical ban on the wrapper starting itself or writing shell text.
//! The wrapper never starts its own executable (a child, a hook command, a shim, an `argv[0]` dispatch), never passes
//!  management words to a process it starts, and never writes shell text or scripts. This scan reads the source of the
//!  release code and fails on any line that does, unless an `ALLOWED` entry justifies it. Each entry must still match
//!  something, so a cleaned file also shrinks the list. The scan is textual by design: the clippy ban on
//!  `std::env::current_exe` (`clippy.toml`) covers the typed call, and this covers the spellings clippy cannot see.
//! Explanations come from the parent process that owns a child; see `doc/planning/cli-git-no-self-invocation.md`.

use std::path::Path;

/// The forbidden texts and the justified exceptions.
#[path = "no_self_invocation_rules_tests.rs"]
mod rules;
use rules::{ALLOWED, Allowed, RULES, Rule};

use crate::source_scan_tests::{CrateRoot, classified_sources, real_roots, source_root};

/// Filesystem-backed controls of this scan on nested layouts.
#[path = "no_self_invocation_fixture_tests.rs"]
mod fixtures;

/// One rule match: the source file as a path relative to `src/native`, the rule that matched, and the line number.
type Finding = (String, &'static str, usize);

/// The release source files under `root`, as `/`-separated paths relative to it: every file the module tree reaches
///  from a crate root through declarations that no `cfg(test)` gates. Test sidecars, binary-level controls and support
///  that only tests compile are told apart by the declarations that reach them, never by file name, so a nested file
///  keeps its own classification; a tree that cannot be fully classified is an error.
fn release_sources_in(root: &Path, roots: &[CrateRoot]) -> Result<Vec<String>, String> {
    let mut found: Vec<String> = Vec::new();
    for file in classified_sources(root, roots)? {
        if !file.test_only {
            found.push(file.path);
        }
    }
    return Ok(found);
}

/// The lines of a source file that are code, with the following line joined so a call split over two lines still reads.
fn code_lines(text: &str) -> Vec<(usize, String, String)> {
    let lines: Vec<&str> = text.lines().collect();
    let mut code: Vec<(usize, String, String)> = Vec::new();
    for (index, line) in lines.iter().enumerate() {
        let trimmed: &str = line.trim_start();
        if trimmed.starts_with("//") {
            continue;
        }
        let next: &str = lines.get(index + 1).map_or("", |following| {
            return following.trim_start();
        });
        code.push((index + 1, trimmed.to_owned(), format!("{trimmed} {next}")));
    }
    return code;
}

/// Every `(relative path, rule id, line number)` the rules find in the release sources of `root`.
fn findings_in(root: &Path, roots: &[CrateRoot]) -> Result<Vec<Finding>, String> {
    let mut found: Vec<Finding> = Vec::new();
    for name in release_sources_in(root, roots)? {
        let text: String = std::fs::read_to_string(root.join(name.as_str()))
            .map_err(|error| return format!("cannot read {name}: {error}"))?;
        for (number, line, joined) in code_lines(text.as_str()) {
            for rule in RULES {
                if (rule.matches)(line.as_str(), joined.as_str()) {
                    found.push((name.clone(), rule.id, number));
                }
            }
        }
    }
    return Ok(found);
}

/// The findings in this crate's own release sources.
fn findings() -> Vec<Finding> {
    return findings_in(&source_root(), &real_roots()).expect("the crate's release sources");
}

/// The findings no `allowed` entry excuses, each as a `file:line [rule] reason` text.
fn unexplained(found: &[Finding], allowed: &[Allowed]) -> Vec<String> {
    return found
        .iter()
        .filter(|(file, rule, _)| {
            return !allowed.iter().any(|entry| {
                return entry.file == file && entry.rule == *rule;
            });
        })
        .map(|(file, rule, number)| {
            let reason: &str = RULES
                .iter()
                .find(|candidate| {
                    return candidate.id == *rule;
                })
                .map_or("", |matched| {
                    return matched.reason;
                });
            return format!("{file}:{number} [{rule}] {reason}");
        })
        .collect();
}

/// The `allowed` entries no finding matches, each as a `file [rule]: why` text.
fn stale(found: &[Finding], allowed: &[Allowed]) -> Vec<String> {
    return allowed
        .iter()
        .filter(|entry| {
            return !found.iter().any(|(file, rule, _)| {
                return entry.file == file && entry.rule == *rule;
            });
        })
        .map(|entry| format!("{} [{}]: {}", entry.file, entry.rule, entry.why))
        .collect();
}

/// No release code starts the wrapper, passes it management words, or writes shell text, beyond the justified list.
#[test]
fn the_release_code_never_starts_the_wrapper_or_writes_shell_text() {
    let unexplained: Vec<String> = unexplained(findings().as_slice(), ALLOWED);
    assert!(
        unexplained.is_empty(),
        "the wrapper never starts itself and never writes shell text; explanations come from the parent that owns the \
         child (doc/planning/cli-git-no-self-invocation.md):\n{}",
        unexplained.join("\n")
    );
}

/// Every justified exception still matches code, so the list shrinks as the code is cleaned.
#[test]
fn every_justified_exception_still_matches_code() {
    let stale: Vec<String> = stale(findings().as_slice(), ALLOWED);
    assert!(stale.is_empty(), "remove these entries from ALLOWED, their code is gone:\n{}", stale.join("\n"));
}

/// The scan reads the release files, and no release code defines a hook command at all.
#[test]
fn the_scan_reads_the_release_sources_and_no_hook_command_is_defined() {
    let root = source_root();
    let sources: Vec<String> = release_sources_in(&root, &real_roots()).expect("the crate's release sources");
    assert!(sources.iter().any(|path| {
        return Path::new(path).ends_with("lfs_pre_push.rs");
    }));
    assert!(sources.iter().all(|path| {
        return !path.ends_with("_tests.rs");
    }));
    let mut definitions: Vec<String> = Vec::new();
    for path in sources {
        let text: String = std::fs::read_to_string(root.join(path)).expect("source file");
        for (_, line, _) in code_lines(text.as_str()) {
            if line.contains(".command=") {
                definitions.push(line);
            }
        }
    }
    assert_eq!(definitions, Vec::<String>::new());
}

/// The rules fire on the text they exist for, so a rule that stopped matching would fail here.
#[test]
fn each_rule_fires_on_its_own_forbidden_text() {
    let samples: [(&str, &str); 6] = [
        ("own-executable", "let exe = std::env::current_exe()?;"),
        ("argv0-dispatch", "let name = std::env::args_os().next();"),
        ("shell-text", "let script = \"#!/bin/sh\\nexit 0\\n\";"),
        ("hook-command", "format!(\"hook.x.command={exe} cli-git sub\")"),
        ("management-word", "Command::new(program).arg(\"cli-git\").arg(\"x\")"),
        ("spawn-own-executable", "Command::new(request.own_executable)"),
    ];
    for (id, sample) in samples {
        let rule: &Rule = RULES
            .iter()
            .find(|candidate| {
                return candidate.id == id;
            })
            .expect("rule exists");
        assert!((rule.matches)(sample, sample), "{id} did not match {sample}");
    }
    assert_eq!(RULES.len(), samples.len());
}