g1t/crates/actions/src/matrix.rs
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| GitHub Actions on g1t, part one: reading workflows | 1 | //! `strategy.matrix`: every combination of its values, less `exclude`, |
| 2 | //! plus `include`, the way GitHub expands it. | |
| 3 | ||
| 4 | use serde_json::{Map, Value}; | |
| 5 | ||
| 6 | /// The most jobs one matrix may make, as on GitHub. | |
| 7 | pub const MAX_JOBS: usize = 256; | |
| 8 | ||
| 9 | /// One combination: the matrix's keys, in the file's order, and values. | |
| 10 | pub type Combination = Map<String, Value>; | |
| 11 | ||
| 12 | /// Expands a matrix. `Ok(vec![])` means it made no jobs, which GitHub | |
| 13 | /// treats as an error the caller reports. | |
| 14 | pub fn expand(matrix: &Value) -> Result<Vec<Combination>, String> { | |
| 15 | let Value::Object(matrix) = matrix else { | |
| 16 | return Err("`strategy.matrix` is a mapping of names to lists of values.".to_owned()); | |
| 17 | }; | |
| 18 | let mut combinations: Vec<Combination> = vec![Map::new()]; | |
| 19 | let mut dimensions = 0; | |
| 20 | for (key, values) in matrix { | |
| 21 | if key == "include" || key == "exclude" { | |
| 22 | continue; | |
| 23 | } | |
| 24 | let Value::Array(values) = values else { | |
| 25 | return Err(format!("`matrix.{key}` is a list of values.")); | |
| 26 | }; | |
| 27 | dimensions += 1; | |
| 28 | let mut next = Vec::with_capacity(combinations.len() * values.len()); | |
| 29 | for combination in &combinations { | |
| 30 | for value in values { | |
| 31 | let mut extended = combination.clone(); | |
| 32 | extended.insert(key.clone(), value.clone()); | |
| 33 | next.push(extended); | |
| 34 | } | |
| 35 | } | |
| 36 | combinations = next; | |
| 37 | if combinations.len() > MAX_JOBS { | |
| 38 | return Err(format!("The matrix makes more than {MAX_JOBS} jobs.")); | |
| 39 | } | |
| 40 | } | |
| 41 | if dimensions == 0 { | |
| 42 | combinations.clear(); | |
| 43 | } | |
| 44 | ||
| 45 | if let Some(exclude) = matrix.get("exclude") { | |
| 46 | let Value::Array(excludes) = exclude else { | |
| 47 | return Err("`matrix.exclude` is a list of combinations.".to_owned()); | |
| 48 | }; | |
| 49 | for exclude in excludes { | |
| 50 | let Value::Object(exclude) = exclude else { | |
| 51 | return Err("Each `matrix.exclude` entry is a mapping.".to_owned()); | |
| 52 | }; | |
| 53 | combinations.retain(|combination| !partial_match(combination, exclude)); | |
| 54 | } | |
| 55 | } | |
| 56 | ||
| 57 | if let Some(include) = matrix.get("include") { | |
| 58 | let Value::Array(includes) = include else { | |
| 59 | return Err("`matrix.include` is a list of combinations.".to_owned()); | |
| 60 | }; | |
| 61 | // The keys of the original matrix, whose values an include may not change. | |
| 62 | let originals: Vec<&String> = matrix.keys().filter(|key| *key != "include" && *key != "exclude").collect(); | |
| 63 | let base_count = combinations.len(); | |
| 64 | for include in includes { | |
| 65 | let Value::Object(include) = include else { | |
| 66 | return Err("Each `matrix.include` entry is a mapping.".to_owned()); | |
| 67 | }; | |
| 68 | let mut added = false; | |
| 69 | for combination in combinations.iter_mut().take(base_count) { | |
| 70 | let overwrites_original = include | |
| 71 | .iter() | |
| 72 | .any(|(key, value)| originals.contains(&key) && combination.get(key).is_some_and(|existing| existing != value)); | |
| 73 | if !overwrites_original { | |
| 74 | for (key, value) in include { | |
| 75 | combination.insert(key.clone(), value.clone()); | |
| 76 | } | |
| 77 | added = true; | |
| 78 | } | |
| 79 | } | |
| 80 | if !added { | |
| 81 | combinations.push(include.clone()); | |
| 82 | } | |
| 83 | } | |
| 84 | } | |
| 85 | if combinations.len() > MAX_JOBS { | |
| 86 | return Err(format!("The matrix makes more than {MAX_JOBS} jobs.")); | |
| 87 | } | |
| 88 | Ok(combinations) | |
| 89 | } | |
| 90 | ||
| 91 | fn partial_match(combination: &Combination, pattern: &Map<String, Value>) -> bool { | |
| 92 | pattern.iter().all(|(key, value)| match (combination.get(key), value) { | |
| 93 | (Some(Value::Object(inner)), Value::Object(pattern)) => partial_match(inner, pattern), | |
| 94 | (Some(actual), expected) => actual == expected, | |
| 95 | (None, _) => false, | |
| 96 | }) | |
| 97 | } | |
| 98 | ||
| 99 | /// A job's name with its combination, as GitHub shows it: | |
| 100 | /// `test (ubuntu-latest, 18)`. Objects in the combination are left out. | |
| 101 | pub fn job_name(name: &str, combination: &Combination) -> String { | |
| 102 | let values: Vec<String> = combination | |
| 103 | .values() | |
| 104 | .filter_map(|value| match value { | |
| 105 | Value::String(text) => Some(text.clone()), | |
| 106 | Value::Number(number) => Some(number.to_string()), | |
| 107 | Value::Bool(flag) => Some(flag.to_string()), | |
| 108 | _ => None, | |
| 109 | }) | |
| 110 | .collect(); | |
| 111 | if values.is_empty() { name.to_owned() } else { format!("{name} ({})", values.join(", ")) } | |
| 112 | } | |
| 113 | ||
| 114 | #[cfg(test)] | |
| 115 | mod tests { | |
| 116 | use super::*; | |
| 117 | use serde_json::json; | |
| 118 | ||
| 119 | fn names(combinations: &[Combination]) -> Vec<String> { | |
| 120 | combinations.iter().map(|c| job_name("test", c)).collect() | |
| 121 | } | |
| 122 | ||
| 123 | #[test] | |
| 124 | fn products_in_file_order() { | |
| 125 | let jobs = expand(&json!({ "os": ["ubuntu-latest", "windows-latest"], "node": [18, 20] })).unwrap(); | |
| 126 | assert_eq!( | |
| 127 | names(&jobs), | |
| 128 | ["test (ubuntu-latest, 18)", "test (ubuntu-latest, 20)", "test (windows-latest, 18)", "test (windows-latest, 20)"] | |
| 129 | ); | |
| 130 | } | |
| 131 | ||
| 132 | #[test] | |
| 133 | fn excludes_partial_matches() { | |
| 134 | let jobs = expand(&json!({ | |
| 135 | "os": ["macos", "windows"], "version": [12, 14, 16], "environment": ["staging", "production"], | |
| 136 | "exclude": [{ "os": "macos", "version": 12, "environment": "production" }, { "os": "windows", "version": 16 }] | |
| 137 | })) | |
| 138 | .unwrap(); | |
| 139 | assert_eq!(jobs.len(), 12 - 1 - 2); | |
| 140 | } | |
| 141 | ||
| 142 | #[test] | |
| 143 | fn includes_extend_or_add_as_github_documents() { | |
| 144 | // GitHub's own example. | |
| 145 | let jobs = expand(&json!({ | |
| 146 | "fruit": ["apple", "pear"], "animal": ["cat", "dog"], | |
| 147 | "include": [ | |
| 148 | { "color": "green" }, | |
| 149 | { "color": "pink", "animal": "cat" }, | |
| 150 | { "fruit": "apple", "shape": "circle" }, | |
| 151 | { "fruit": "banana" }, | |
| 152 | { "fruit": "banana", "animal": "cat" } | |
| 153 | ] | |
| 154 | })) | |
| 155 | .unwrap(); | |
| 156 | let expected = vec![ | |
| 157 | json!({ "fruit": "apple", "animal": "cat", "color": "pink", "shape": "circle" }), | |
| 158 | json!({ "fruit": "apple", "animal": "dog", "color": "green", "shape": "circle" }), | |
| 159 | json!({ "fruit": "pear", "animal": "cat", "color": "pink" }), | |
| 160 | json!({ "fruit": "pear", "animal": "dog", "color": "green" }), | |
| 161 | json!({ "fruit": "banana" }), | |
| 162 | json!({ "fruit": "banana", "animal": "cat" }), | |
| 163 | ]; | |
| 164 | let got: Vec<Value> = jobs.into_iter().map(Value::Object).collect(); | |
| 165 | assert_eq!(got, expected); | |
| 166 | } | |
| 167 | ||
| 168 | #[test] | |
| 169 | fn include_only_and_limits() { | |
| 170 | let jobs = expand(&json!({ "include": [{ "site": "a" }, { "site": "b" }] })).unwrap(); | |
| 171 | assert_eq!(names(&jobs), ["test (a)", "test (b)"]); | |
| 172 | let big: Vec<u32> = (0..20).collect(); | |
| 173 | assert!(expand(&json!({ "a": big, "b": big })).unwrap_err().contains("256")); | |
| 174 | assert!(expand(&json!({ "os": "linux" })).is_err()); | |
| 175 | assert!(expand(&json!({})).unwrap().is_empty()); | |
| 176 | } | |
| 177 | } |