diff --git a/src/build/arg/mod.rs b/src/build/arg/mod.rs index 54f6f96bad7..111b6cff846 100644 --- a/src/build/arg/mod.rs +++ b/src/build/arg/mod.rs @@ -3050,25 +3050,37 @@ impl<'help> Arg<'help> { /// assert_eq!(m.value_of("flag"), Some("env")); /// ``` /// - /// In this example, we show the flag being raised but with no value because - /// of not setting [`Arg::takes_value(true)`]: + /// In this example, because [`Arg::takes_value(false)`] (by default), + /// `prog` is a flag that accepts an optional, case-insensitive boolean literal. + /// A `false` literal is `n`, `no`, `f`, `false`, `off` or `0`. + /// An absent environment variable will also be considered as `false`. + /// Anything else will considered as `true`. /// /// ```rust /// # use std::env; /// # use clap::{App, Arg}; /// - /// env::set_var("MY_FLAG", "env"); + /// env::set_var("TRUE_FLAG", "true"); + /// env::set_var("FALSE_FLAG", "0"); /// /// let m = App::new("prog") - /// .arg(Arg::new("flag") - /// .long("flag") - /// .env("MY_FLAG")) + /// .arg(Arg::new("true_flag") + /// .long("true_flag") + /// .env("TRUE_FLAG")) + /// .arg(Arg::new("false_flag") + /// .long("false_flag") + /// .env("FALSE_FLAG")) + /// .arg(Arg::new("absent_flag") + /// .long("absent_flag") + /// .env("ABSENT_FLAG")) /// .get_matches_from(vec![ /// "prog" /// ]); /// - /// assert!(m.is_present("flag")); - /// assert_eq!(m.value_of("flag"), None); + /// assert!(m.is_present("true_flag")); + /// assert_eq!(m.value_of("true_flag"), None); + /// assert!(!m.is_present("false_flag")); + /// assert!(!m.is_present("absent_flag")); /// ``` /// /// In this example, we show the variable coming from an option on the CLI: diff --git a/src/parse/parser.rs b/src/parse/parser.rs index 53b705363a7..d6ef4cb081c 100644 --- a/src/parse/parser.rs +++ b/src/parse/parser.rs @@ -16,7 +16,7 @@ use crate::{ parse::features::suggestions, parse::{ArgMatcher, SubCommand}, parse::{Validator, ValueType}, - util::{termcolor::ColorChoice, ArgStr, ChildGraph, Id}, + util::{str_to_bool, termcolor::ColorChoice, ArgStr, ChildGraph, Id}, INTERNAL_ERROR_MSG, INVALID_UTF8, }; @@ -1773,39 +1773,60 @@ impl<'help, 'app> Parser<'help, 'app> { trailing_values: bool, ) -> ClapResult<()> { if self.app.is_set(AS::DisableEnv) { + debug!("Parser::add_env: Env vars disabled, quitting"); return Ok(()); } - for a in self.app.args.args() { - // Use env only if the arg was not present among command line args - if matcher.get(&a.id).map_or(true, |a| a.occurs == 0) { - if let Some((_, Some(ref val))) = a.env { - let val = ArgStr::new(val); - if a.is_set(ArgSettings::TakesValue) { - self.add_val_to_arg( - a, - val, - matcher, - ValueType::EnvVariable, - false, - trailing_values, - ); - } else { - match self.check_for_help_and_version_str(&val) { - Some(ParseResult::HelpFlag) => { - return Err(self.help_err(true)); - } - Some(ParseResult::VersionFlag) => { - return Err(self.version_err(true)); - } - _ => (), - } - matcher.add_index_to(&a.id, self.cur_idx.get(), ValueType::EnvVariable); + self.app.args.args().try_for_each(|a| { + // Use env only if the arg was absent among command line args, + // early return if this is not the case. + if matcher.get(&a.id).map_or(false, |a| a.occurs != 0) { + debug!("Parser::add_env: Skipping existing arg `{}`", a); + return Ok(()); + } + + debug!("Parser::add_env: Checking arg `{}`", a); + if let Some((_, Some(ref val))) = a.env { + let val = ArgStr::new(val); + + if a.is_set(ArgSettings::TakesValue) { + debug!( + "Parser::add_env: Found an opt with value={:?}, trailing={:?}", + val, trailing_values + ); + self.add_val_to_arg( + a, + val, + matcher, + ValueType::EnvVariable, + false, + trailing_values, + ); + return Ok(()); + } + + debug!("Parser::add_env: Checking for help and version"); + // Early return on `HelpFlag` or `VersionFlag`. + match self.check_for_help_and_version_str(&val) { + Some(ParseResult::HelpFlag) => { + return Err(self.help_err(true)); + } + Some(ParseResult::VersionFlag) => { + return Err(self.version_err(true)); } + _ => (), + } + + debug!("Parser::add_env: Found a flag with value `{:?}`", val); + let predicate = str_to_bool(val.to_string_lossy()); + debug!("Parser::add_env: Found boolean literal `{}`", predicate); + if predicate { + matcher.add_index_to(&a.id, self.cur_idx.get(), ValueType::EnvVariable); } } - } - Ok(()) + + Ok(()) + }) } /// Increase occurrence of specific argument and the grouped arg it's in. diff --git a/src/util/mod.rs b/src/util/mod.rs index 1049f7e2ddb..eb7b8331e58 100644 --- a/src/util/mod.rs +++ b/src/util/mod.rs @@ -4,10 +4,11 @@ mod argstr; mod fnv; mod graph; mod id; +mod str_to_bool; pub use self::fnv::Key; -pub(crate) use self::{argstr::ArgStr, graph::ChildGraph, id::Id}; +pub(crate) use self::{argstr::ArgStr, graph::ChildGraph, id::Id, str_to_bool::str_to_bool}; pub(crate) use vec_map::VecMap; #[cfg(feature = "color")] diff --git a/src/util/str_to_bool.rs b/src/util/str_to_bool.rs new file mode 100644 index 00000000000..58e2efa63d2 --- /dev/null +++ b/src/util/str_to_bool.rs @@ -0,0 +1,15 @@ +/// True values are `y`, `yes`, `t`, `true`, `on`, and `1`. +// pub(crate) const TRUE_LITERALS: [&str; 6] = ["y", "yes", "t", "true", "on", "1"]; + +/// False values are `n`, `no`, `f`, `false`, `off`, and `0`. +const FALSE_LITERALS: [&str; 6] = ["n", "no", "f", "false", "off", "0"]; + +/// Converts a string literal representation of truth to true or false. +/// +/// `false` values are `n`, `no`, `f`, `false`, `off`, and `0` (case insensitive). +/// +/// Any other value will be considered as `true`. +pub(crate) fn str_to_bool(val: impl AsRef) -> bool { + let pat: &str = &val.as_ref().to_lowercase(); + !FALSE_LITERALS.contains(&pat) +} diff --git a/tests/env.rs b/tests/env.rs index 636c453319f..2d4dc912301 100644 --- a/tests/env.rs +++ b/tests/env.rs @@ -23,18 +23,23 @@ fn env() { } #[test] -fn env_no_takes_value() { - env::set_var("CLP_TEST_ENV", "env"); +fn env_bool_literal() { + env::set_var("CLP_TEST_FLAG_TRUE", "On"); + env::set_var("CLP_TEST_FLAG_FALSE", "nO"); let r = App::new("df") - .arg(Arg::from("[arg] 'some opt'").env("CLP_TEST_ENV")) + .arg(Arg::from("[present] 'some opt'").env("CLP_TEST_FLAG_TRUE")) + .arg(Arg::from("[negated] 'some another opt'").env("CLP_TEST_FLAG_FALSE")) + .arg(Arg::from("[absent] 'some third opt'").env("CLP_TEST_FLAG_ABSENT")) .try_get_matches_from(vec![""]); assert!(r.is_ok()); let m = r.unwrap(); - assert!(m.is_present("arg")); - assert_eq!(m.occurrences_of("arg"), 0); - assert_eq!(m.value_of("arg"), None); + assert!(m.is_present("present")); + assert_eq!(m.occurrences_of("present"), 0); + assert_eq!(m.value_of("present"), None); + assert!(!m.is_present("negated")); + assert!(!m.is_present("absent")); } #[test]