monochromatic-git-policy-cli 0.5.2

Repository-owned Git policy wrapper: forwards Git commands and checks commits against configured policies.
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

//! Controls for the new-side span derivation, each one a differential against real Git's `diff -U0` for the same file:
//! the relation under test is that the three-line-context patch yields the spans a zero-context diff's new-side headers
//! name.

use super::*;
use crate::test_support::{fixture, git, git_text, remove, repository};
use std::path::{Path, PathBuf};

/// Lines in the fixture file; large enough that every edit below sits apart from the others.
const FILE_LINES: usize = 120;

/// The numbered lines of the fixture file.
fn numbered(count: usize) -> String {
    return (1..=count).map(|number| return format!("line {number}\n")).collect::<String>();
}

/// The spans a zero-context diff's new-side headers name: `+c,d` is lines `c` to `c + d - 1`, and `+c,0` is the line
/// after `c`, where the removed lines stood.
fn headers_spans(zero_context_diff: &str) -> Vec<NewSpan> {
    let mut spans: Vec<NewSpan> = Vec::new();
    for line in zero_context_diff.split('\n') {
        let Some(rest) = line.strip_prefix("@@ -") else {
            continue;
        };
        let new: &str = rest.split(' ').nth(1).and_then(|side| return side.strip_prefix('+')).expect("new side");
        let (start_text, length_text) = new.split_once(',').unwrap_or((new, "1"));
        let start: u64 = start_text.parse::<u64>().expect("start");
        let length: u64 = length_text.parse::<u64>().expect("length");
        spans.push(if length == 0 { NewSpan { first: start + 1, last: start + 1 } } else { NewSpan { first: start, last: start + length - 1 } });
    }
    return spans;
}

/// A repository whose last commit changed `name` from `before` to `after`.
fn changed_repository(test: &str, name: &str, before: &str, after: &str) -> (PathBuf, PathBuf) {
    let parent: PathBuf = fixture(test);
    let root: PathBuf = repository(parent.as_path(), "repo");
    std::fs::create_dir_all(root.join(name).parent().expect("parent")).expect("directories");
    std::fs::write(root.join(name), before).expect("write before");
    git(root.as_path(), &["add", "--", name]);
    git(root.as_path(), &["commit", "--quiet", "--message=before"]);
    std::fs::write(root.join(name), after).expect("write after");
    git(root.as_path(), &["add", "--", name]);
    git(root.as_path(), &["commit", "--quiet", "--message=after"]);
    return (parent, root);
}

/// Both sides of the differential for one file of the last commit.
fn both_sides(root: &Path, name: &str) -> (Vec<NewSpan>, Vec<NewSpan>) {
    let patch: String = git_text(root, &["show", "--format=", "--patch", "HEAD"]);
    let patch_lines: Vec<&str> = patch.split('\n').collect();
    let zero: String = git_text(root, &["diff", "-U0", "HEAD^", "HEAD", "--", name]);
    return (new_spans(patch_lines.as_slice(), name), headers_spans(zero.as_str()));
}

/// Replacement, insertion, deletion, an edit at the first line and an append all derive the same spans.
#[test]
fn edits_derive_the_zero_context_spans() {
    let before: String = numbered(FILE_LINES);
    let mut lines: Vec<String> = before.lines().map(String::from).collect();
    lines[4] = String::from("replaced");
    lines.insert(20, String::from("inserted"));
    lines.drain(40..43);
    lines[0] = String::from("first replaced");
    lines.push(String::from("appended"));
    let after: String = format!("{}\n", lines.join("\n"));
    let (parent, root) = changed_repository("patch-edits", "src/a.ts", before.as_str(), after.as_str());
    let (derived, expected) = both_sides(root.as_path(), "src/a.ts");
    assert!(expected.len() > 1);
    assert_eq!(derived, expected);
    remove(parent.as_path());
}

/// Two edits close enough for Git to merge into one three-line-context hunk stay two spans.
#[test]
fn near_edits_in_one_hunk_stay_separate() {
    let before: String = numbered(FILE_LINES);
    let mut lines: Vec<String> = before.lines().map(String::from).collect();
    lines[10] = String::from("one");
    lines[13] = String::from("two");
    let after: String = format!("{}\n", lines.join("\n"));
    let (parent, root) = changed_repository("patch-near", "a.rs", before.as_str(), after.as_str());
    let patch: String = git_text(root.as_path(), &["show", "--format=", "--patch", "HEAD"]);
    assert_eq!(patch.matches("\n@@ ").count() + usize::from(patch.starts_with("@@ ")), 1, "one patch hunk");
    let (derived, expected) = both_sides(root.as_path(), "a.rs");
    assert_eq!(derived.len(), 2);
    assert_eq!(derived, expected);
    remove(parent.as_path());
}

/// A file without a trailing newline and a path with a space still match their section.
#[test]
fn unusual_endings_and_spaces_match() {
    let before: String = numbered(FILE_LINES);
    let after: String = format!("{}no newline", before.replace("line 60\n", "sixty\n"));
    let (parent, root) = changed_repository("patch-space", "dir name/b c.mjs", before.as_str(), after.as_str());
    let (derived, expected) = both_sides(root.as_path(), "dir name/b c.mjs");
    assert!(!expected.is_empty());
    assert_eq!(derived, expected);
    remove(parent.as_path());
}

/// A new file is one span over all its lines.
#[test]
fn a_new_file_is_one_span_over_all_lines() {
    let parent: PathBuf = fixture("patch-new");
    let root: PathBuf = repository(parent.as_path(), "repo");
    let count: usize = 5;
    std::fs::write(root.join("new.rs"), numbered(count)).expect("write");
    git(root.as_path(), &["add", "--", "new.rs"]);
    git(root.as_path(), &["commit", "--quiet", "--message=new"]);
    let (derived, expected) = both_sides(root.as_path(), "new.rs");
    assert_eq!(derived, vec![NewSpan { first: 1, last: u64::try_from(count).expect("small") }]);
    assert_eq!(derived, expected);
    remove(parent.as_path());
}

/// A rename with an edit is read under its new name, with the spans a rename-detecting zero-context diff shows.
#[test]
fn a_rename_is_read_under_its_new_name() {
    let before: String = numbered(FILE_LINES);
    let after: String = before.replace("line 60\n", "sixty\n");
    let parent: PathBuf = fixture("patch-rename");
    let root: PathBuf = repository(parent.as_path(), "repo");
    std::fs::write(root.join("old.ts"), before.as_str()).expect("write");
    git(root.as_path(), &["add", "--", "old.ts"]);
    git(root.as_path(), &["commit", "--quiet", "--message=old"]);
    git(root.as_path(), &["mv", "old.ts", "renamed.ts"]);
    std::fs::write(root.join("renamed.ts"), after.as_str()).expect("write");
    git(root.as_path(), &["add", "--", "renamed.ts"]);
    git(root.as_path(), &["commit", "--quiet", "--message=rename"]);
    let patch: String = git_text(root.as_path(), &["show", "--format=", "--patch", "HEAD"]);
    assert!(patch.contains("rename to renamed.ts"), "{patch}");
    let patch_lines: Vec<&str> = patch.split('\n').collect();
    let zero: String = git_text(root.as_path(), &["diff", "-U0", "-M", "HEAD^", "HEAD"]);
    let derived: Vec<NewSpan> = new_spans(patch_lines.as_slice(), "renamed.ts");
    assert!(!derived.is_empty());
    assert_eq!(derived, headers_spans(zero.as_str()));
    remove(parent.as_path());
}

/// An insertion early in a file moves every later span down with it, which the old-side reading missed.
#[test]
fn spans_after_an_insertion_are_in_new_file_lines() {
    let before: String = numbered(FILE_LINES);
    let inserted: usize = 7;
    let mut lines: Vec<String> = before.lines().map(String::from).collect();
    for number in 0..inserted {
        lines.insert(2, format!("inserted {number}"));
    }
    lines[100] = String::from("late edit");
    let after: String = format!("{}\n", lines.join("\n"));
    let (parent, root) = changed_repository("patch-shift", "s.ts", before.as_str(), after.as_str());
    let (derived, expected) = both_sides(root.as_path(), "s.ts");
    assert_eq!(derived, expected);
    let late: NewSpan = *derived.last().expect("a late span");
    assert_eq!(after.lines().nth(usize::try_from(late.first).expect("fits") - 1), Some("late edit"));
    remove(parent.as_path());
}

/// A path the patch does not mention, and a mode-only change, have no spans.
#[test]
fn absent_paths_and_hunkless_sections_have_no_spans() {
    let before: String = numbered(FILE_LINES);
    let (parent, root) = changed_repository("patch-absent", "a.ts", before.as_str(), format!("{before}x\n").as_str());
    let patch: String = git_text(root.as_path(), &["show", "--format=", "--patch", "HEAD"]);
    let patch_lines: Vec<&str> = patch.split('\n').collect();
    assert!(new_spans(patch_lines.as_slice(), "other.ts").is_empty());
    assert!(new_spans(&[], "a.ts").is_empty());
    let hunkless: Vec<&str> = vec!["diff --git a/m.ts b/m.ts", "old mode 100644", "new mode 100755"];
    assert!(new_spans(hunkless.as_slice(), "m.ts").is_empty());
    remove(parent.as_path());
}