use std::convert::TryFrom; use crate::{file, file::init, parse, parse::section, path::interpolate, File}; /// Represents the errors that may occur when calling [`File::from_env()`].#[derive(Debug, thiserror::Error)]#[allow(missing_docs)]pub enum Error {    #[error("GIT_CONFIG_COUNT was not a positive integer: {}", .input)]    InvalidConfigCount { input: String },    #[error("GIT_CONFIG_KEY_{} was not set", .key_id)]    InvalidKeyId { key_id: usize },    #[error("GIT_CONFIG_KEY_{} was set to an invalid value: {}", .key_id, .key_val)]    InvalidKeyValue { key_id: usize, key_val: String },    #[error("GIT_CONFIG_VALUE_{} was not set", .value_id)]    InvalidValueId { value_id: usize },    #[error(transparent)]    PathInterpolationError(#[from] interpolate::Error),    #[error(transparent)]    Includes(#[from] init::includes::Error),    #[error(transparent)]    Section(#[from] section::header::Error),    #[error(transparent)]    Key(#[from] section::key::Error),} /// Instantiation from environment variablesimpl File<'static> {    /// Generates a config from `GIT_CONFIG_*` environment variables or returns `Ok(None)` if no configuration was found.    /// See [`git-config`'s documentation] for more information on the environment variables in question.    ///    /// With `options` configured, it's possible to resolve `include.path` or `includeIf.<condition>.path` directives as well.    ///    /// [`git-config`'s documentation]: https://git-scm.com/docs/git-config#Documentation/git-config.txt-GITCONFIGCOUNT    pub fn from_env(options: init::Options<'_>) -> Result<Option<File<'static>>, Error> {        use std::env;        let count: usize = match env::var("GIT_CONFIG_COUNT") {            Ok(v) => v.parse().map_err(|_| Error::InvalidConfigCount { input: v })?,            Err(_) => return Ok(None),        };         if count == 0 {            return Ok(None);        }         let meta = file::Metadata {            path: None,            source: crate::Source::Env,            level: 0,            trust: git_sec::Trust::Full,        };        let mut config = File::new(meta);        for i in 0..count {            let key = env::var(format!("GIT_CONFIG_KEY_{}", i)).map_err(|_| Error::InvalidKeyId { key_id: i })?;            let value = env::var_os(format!("GIT_CONFIG_VALUE_{}", i)).ok_or(Error::InvalidValueId { value_id: i })?;            let key = parse::key(&key).ok_or_else(|| Error::InvalidKeyValue {                key_id: i,                key_val: key.to_string(),            })?;             config                .section_mut_or_create_new(key.section_name, key.subsection_name)?                .push(                    section::Key::try_from(key.value_name.to_owned())?,                    Some(                        git_path::os_str_into_bstr(&value)                            .expect("no illformed UTF-8")                            .as_ref()                            .into(),                    ),                );        }         let mut buf = Vec::new();        init::includes::resolve(&mut config, &mut buf, options)?;        Ok(Some(config))    }}