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
//! What:
//! The proof, from files alone, that no configuration scope Git reads for repository discovery sets `core.bare` or
//! `core.worktree`.
//! Why:
//! `git rev-parse` classifies a repository from the discovered directory plus those two keys of any scope;
//! the in-process location reader may only answer when none of the files it can see mentions either key,
//! so the check follows every `include` and `includeIf` path without evaluating its condition (a
//! conditional include that mentions a key is enough to leave the question to Git).
//!
//! In TS you'd write (pseudocode):
//! ```ts
//! const safe: boolean | undefined = noScopeSetsBareOrWorktree({ home, env }); // undefined: ask Git
//! ```
use super::repo_read_config_text::{CONFIG_TEXT_LIMIT, ConfigEntry, parse_bool, parse_config_text};
use std::ffi::OsString;
use std::path::{Path, PathBuf};
/// How many nested includes are followed before the reader gives up.
const INCLUDE_DEPTH_LIMIT: usize = 10;
/// The keys whose presence in any file makes the location reader decline.
const DISCOVERY_KEYS: [&str; 2] = ["core.bare", "core.worktree"];
/// The keys whose presence in any file makes the content readers decline (listings, cached diffs, `show`).
const CONTENT_KEYS: [&str; 11] = [
"diff.relative",
"core.ignorecase",
"core.precomposeunicode",
"core.sparsecheckout",
"core.splitindex",
"index.sparse",
"diff.orderfile",
"diff.renames",
"diff.ignoresubmodules",
"log.showsignature",
"i18n.logoutputencoding",
];
/// What:
/// The text of a configuration file, following links, or `Some(None)` when the file does not exist.
/// Why:
/// Dotfile managers link `~/.gitconfig`; Git follows the link, so does this read.
///
/// In TS you'd write (pseudocode):
/// ```ts
/// const text = await readFile(path).catch(notFoundIsUndefined); // other failures: ask Git
/// ```
pub fn read_following(path: &Path) -> Option<Option<Vec<u8>>> {
let metadata = match std::fs::metadata(path) {
Ok(found) => found,
Err(error) if error.kind() == std::io::ErrorKind::NotFound => return Some(None),
Err(_) => return None,
};
if !metadata.is_file() || metadata.len() > CONFIG_TEXT_LIMIT as u64 {
return None;
}
return std::fs::read(path).ok().map(Some);
}
/// The path an include value names: `~/x` below `home`, an absolute path as is, a relative path beside the including file.
pub fn include_target(value: &[u8], including: &Path, home: Option<&Path>) -> Option<PathBuf> {
let text: &str = std::str::from_utf8(value).ok()?;
if let Some(rest) = text.strip_prefix("~/") {
return Some(home?.join(rest));
}
if text.starts_with('~') || text.is_empty() {
return None;
}
let path: &Path = Path::new(text);
if path.is_absolute() {
return Some(path.to_path_buf());
}
return Some(including.parent()?.join(path));
}
/// Whether an entry key names an include path (`include.path` or `includeif.<condition>.path`).
pub fn is_include_key(key: &str) -> bool {
return key == "include.path" || (key.starts_with("includeif.") && key.ends_with(".path"));
}
/// Whether a key decides how Git discovers the repository.
pub fn discovery_key(key: &str) -> bool {
return DISCOVERY_KEYS.contains(&key);
}
/// Whether a key can change what the content queries (listings, cached diffs, `show`) print.
pub fn content_key(key: &str) -> bool {
return CONTENT_KEYS.contains(&key) || (key.starts_with("submodule.") && key.ends_with(".ignore"));
}
/// What:
/// Whether the file at `path`, and every file it includes, avoids every key `declines` names;
/// `None` when any file cannot be read or parsed.
/// Why:
/// A missing file is an empty file to Git, so it passes.
///
/// In TS you'd write (pseudocode):
/// ```ts
/// function avoidsKeys(path: string, declines: (key: string) => boolean, depth = 0): boolean | undefined;
/// ```
pub fn file_avoids_keys(path: &Path, home: Option<&Path>, depth: usize, declines: &dyn Fn(&str) -> bool) -> Option<bool> {
if depth > INCLUDE_DEPTH_LIMIT {
return None;
}
let Some(text) = read_following(path)? else {
return Some(true);
};
let entries: Vec<ConfigEntry> = parse_config_text(text.as_slice())?;
return entries_avoid_keys(entries.as_slice(), path, home, depth, declines);
}
/// The same proof for entries already parsed from `path` (so the repository's own file is read once).
pub fn entries_avoid_keys(
entries: &[ConfigEntry],
path: &Path,
home: Option<&Path>,
depth: usize,
declines: &dyn Fn(&str) -> bool,
) -> Option<bool> {
for entry in entries {
if declines(entry.key.as_str()) {
return Some(false);
}
if is_include_key(entry.key.as_str()) {
let target: PathBuf = include_target(entry.value.as_deref()?, path, home)?;
if !file_avoids_keys(target.as_path(), home, depth + 1, declines)? {
return Some(false);
}
}
}
return Some(true);
}
/// The discovery proof for one file.
pub fn file_avoids_discovery_keys(path: &Path, home: Option<&Path>, depth: usize) -> Option<bool> {
return file_avoids_keys(path, home, depth, &discovery_key);
}
/// What:
/// The environment facts that decide which system and global configuration files Git reads.
/// Why:
/// `GIT_CONFIG_NOSYSTEM`, `GIT_CONFIG_SYSTEM` and `GIT_CONFIG_GLOBAL` move or remove the files, and the XDG file is
/// read next to `~/.gitconfig` unless `GIT_CONFIG_GLOBAL` replaces both; a value type lets a control inject them.
///
/// In TS you'd write (pseudocode):
/// ```ts
/// type ScopeEnvironment = { home?: string; xdg?: string; noSystem: boolean; system?: string; global?: string };
/// ```
#[derive(Clone, Debug, Default)]
pub struct ScopeEnvironment {
/// `HOME`, when set and not empty.
pub home: Option<PathBuf>,
/// `XDG_CONFIG_HOME`, when set and not empty.
pub xdg: Option<PathBuf>,
/// Whether `GIT_CONFIG_NOSYSTEM` is set.
pub no_system: bool,
/// `GIT_CONFIG_SYSTEM`.
pub system: Option<PathBuf>,
/// The path the real Git compiles in, read when `GIT_CONFIG_SYSTEM` is not set; learned from that Git
/// (`git_system_config`), and `None` when it is not known, which makes the scope unresolvable.
pub system_default: Option<PathBuf>,
/// `GIT_CONFIG_GLOBAL`.
pub global: Option<PathBuf>,
/// Whether some fact cannot be settled from the variables alone: a relative path (Git resolves it against the
/// directory it runs in) or a `GIT_CONFIG_NOSYSTEM` that is not a boolean. Readers that need the files decline.
pub unresolvable: bool,
}
impl ScopeEnvironment {
/// The facts of an environment as a child would see it: the process variables with a run's additions over them, which
/// include the forward-target variable naming the real Git; the wrapper's own environment does not carry it, so there is
/// deliberately no constructor that reads the process environment alone.
pub fn from_variables(variables: &[(OsString, OsString)]) -> ScopeEnvironment {
let find = |name: &str| -> Option<OsString> {
return variables.iter().rev().find(|(candidate, _)| { return candidate == name; }).map(|(_, value)| { return value.clone(); });
};
let nonempty = |name: &str| -> Option<PathBuf> {
return find(name).filter(|value| { return !value.is_empty(); }).map(PathBuf::from);
};
// `GIT_CONFIG_NOSYSTEM` is a boolean: absent or false reads the system file, an empty value is false.
let (no_system, boolean_ok): (bool, bool) = match find("GIT_CONFIG_NOSYSTEM") {
None => (false, true),
Some(value) if value.is_empty() => (false, true),
Some(value) => match parse_bool(Some(value.as_encoded_bytes())) {
Some(truth) => (truth, true),
None => (true, false),
},
};
let mut scope: ScopeEnvironment = ScopeEnvironment {
home: nonempty("HOME"),
xdg: nonempty("XDG_CONFIG_HOME"),
no_system,
system: find("GIT_CONFIG_SYSTEM").map(PathBuf::from),
system_default: None,
global: find("GIT_CONFIG_GLOBAL").map(PathBuf::from),
unresolvable: !boolean_ok,
};
// Git reads its compiled-in system file unless the environment removes or replaces it.
if boolean_ok && !scope.no_system && scope.system.is_none() {
scope.system_default = super::git_system_config::system_config_for(variables);
scope.unresolvable = scope.system_default.is_none();
}
let relative: bool = [&scope.home, &scope.xdg, &scope.system, &scope.global].iter().any(|path| { return path.as_ref().is_some_and(|found| { return !found.is_absolute(); }); });
scope.unresolvable = scope.unresolvable || relative;
return scope;
}
/// The files with the scope name `config --show-scope` gives each, in Git's order.
pub fn labelled_files(&self) -> Vec<(&'static str, PathBuf)> {
let mut labelled: Vec<(&'static str, PathBuf)> = Vec::new();
let mut files: Vec<PathBuf> = self.files();
if !self.no_system && (self.system.is_some() || self.system_default.is_some()) {
labelled.push(("system", files.remove(0)));
}
labelled.extend(files.into_iter().map(|file| { return ("global", file); }));
return labelled;
}
/// The system and global files Git reads in this environment, in its order.
pub fn files(&self) -> Vec<PathBuf> {
let mut files: Vec<PathBuf> = Vec::new();
if !self.no_system {
files.extend(self.system.clone().or_else(|| { return self.system_default.clone(); }));
}
if let Some(global) = &self.global {
files.push(global.clone());
return files;
}
match (&self.xdg, &self.home) {
(Some(directory), _) => files.push(directory.join("git/config")),
(None, Some(base)) => files.push(base.join(".config/git/config")),
(None, None) => {}
}
if let Some(base) = &self.home {
files.push(base.join(".gitconfig"));
}
return files;
}
}
/// What:
/// Whether the system and global configuration files, with everything they include, avoid the discovery keys.
/// Why:
/// The repository-level files are checked by the layout reader; these are the scopes beyond the repository.
///
/// In TS you'd write (pseudocode):
/// ```ts
/// scopeFiles(env).every((file) => avoidsDiscoveryKeys(file)); // undefined when unreadable
/// ```
pub fn outer_scopes_avoid_keys(scope: &ScopeEnvironment, declines: &dyn Fn(&str) -> bool) -> Option<bool> {
if scope.unresolvable {
return None;
}
for file in scope.files() {
if !file_avoids_keys(file.as_path(), scope.home.as_deref(), 0, declines)? {
return Some(false);
}
}
return Some(true);
}
#[cfg(test)]
#[path = "repo_read_config_scan_tests.rs"]
mod tests;