Merge pull request #495 from dandavison/493-GIT_CONFIG_PARAMETERS

Honor GIT_CONFIG_PARAMETERS env var

4 files changed, 384 insertions, 109 deletions

diff --git a/src/git_config/git_config.rs b/src/git_config/git_config.rs
deleted file mode 100644
index ab831b31..00000000
--- a/src/git_config/git_config.rs
+++ /dev/null
@@ -1,101 +0,0 @@
-#[cfg(test)]
-use std::path::Path;
-use std::process;
-
-pub struct GitConfig {
-    config: git2::Config,
-    pub enabled: bool,
-    pub repo: Option<git2::Repository>,
-}
-
-impl GitConfig {
-    pub fn try_create() -> Option<Self> {
-        let repo = match std::env::current_dir() {
-            Ok(dir) => git2::Repository::discover(dir).ok(),
-            _ => None,
-        };
-        let config = match &repo {
-            Some(repo) => repo.config().ok(),
-            None => git2::Config::open_default().ok(),
-        };
-        match config {
-            Some(mut config) => {
-                let config = config.snapshot().unwrap_or_else(|err| {
-                    eprintln!("Failed to read git config: {}", err);
-                    process::exit(1)
-                });
-                Some(Self {
-                    config,
-                    repo,
-                    enabled: true,
-                })
-            }
-            None => None,
-        }
-    }
-
-    #[cfg(test)]
-    pub fn from_path(path: &Path) -> Self {
-        Self {
-            config: git2::Config::open(path).unwrap(),
-            repo: None,
-            enabled: true,
-        }
-    }
-
-    pub fn get<T>(&self, key: &str) -> Option<T>
-    where
-        T: GitConfigGet,
-    {
-        if self.enabled {
-            T::git_config_get(key, self)
-        } else {
-            None
-        }
-    }
-}
-
-pub trait GitConfigGet {
-    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self>
-    where
-        Self: Sized;
-}
-
-impl GitConfigGet for String {
-    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
-        git_config.config.get_string(key).ok()
-    }
-}
-
-impl GitConfigGet for Option<String> {
-    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
-        match git_config.config.get_string(key) {
-            Ok(value) => Some(Some(value)),
-            _ => None,
-        }
-    }
-}
-
-impl GitConfigGet for bool {
-    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
-        git_config.config.get_bool(key).ok()
-    }
-}
-
-impl GitConfigGet for usize {
-    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
-        match git_config.config.get_i64(key) {
-            Ok(value) => Some(value as usize),
-            _ => None,
-        }
-    }
-}
-
-impl GitConfigGet for f64 {
-    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
-        match git_config.config.get_string(key) {
-            Ok(value) => value.parse::<f64>().ok(),
-            _ => None,
-        }
-    }
-}
diff --git a/src/git_config/mod.rs b/src/git_config/mod.rs
index 9c7b2212..827446e1 100644
--- a/src/git_config/mod.rs
+++ b/src/git_config/mod.rs
@@ -1,6 +1,198 @@
-pub mod git_config;
-pub mod git_config_entry;
+mod git_config_entry;
 
-pub use crate::git_config::git_config::{GitConfig, GitConfigGet};
-pub use crate::git_config::git_config_entry::GitConfigEntry;
-pub use crate::git_config::git_config_entry::GitRemoteRepo;
+pub use git_config_entry::{GitConfigEntry, GitRemoteRepo};
+
+use regex::Regex;
+use std::collections::HashMap;
+use std::env;
+#[cfg(test)]
+use std::path::Path;
+use std::process;
+
+use lazy_static::lazy_static;
+
+pub struct GitConfig {
+    config: git2::Config,
+    config_from_env_var: HashMap<String, String>,
+    pub enabled: bool,
+    pub repo: Option<git2::Repository>,
+}
+
+impl GitConfig {
+    pub fn try_create() -> Option<Self> {
+        let repo = match std::env::current_dir() {
+            Ok(dir) => git2::Repository::discover(dir).ok(),
+            _ => None,
+        };
+        let config = match &repo {
+            Some(repo) => repo.config().ok(),
+            None => git2::Config::open_default().ok(),
+        };
+        match config {
+            Some(mut config) => {
+                let config = config.snapshot().unwrap_or_else(|err| {
+                    eprintln!("Failed to read git config: {}", err);
+                    process::exit(1)
+                });
+                Some(Self {
+                    config,
+                    config_from_env_var: parse_config_from_env_var(),
+                    repo,
+                    enabled: true,
+                })
+            }
+            None => None,
+        }
+    }
+
+    #[cfg(test)]
+    pub fn from_path(path: &Path, honor_env_var: bool) -> Self {
+        Self {
+            config: git2::Config::open(path).unwrap(),
+            config_from_env_var: if honor_env_var {
+                parse_config_from_env_var()
+            } else {
+                HashMap::new()
+            },
+            repo: None,
+            enabled: true,
+        }
+    }
+
+    pub fn get<T>(&self, key: &str) -> Option<T>
+    where
+        T: GitConfigGet,
+    {
+        if self.enabled {
+            T::git_config_get(key, self)
+        } else {
+            None
+        }
+    }
+}
+
+fn parse_config_from_env_var() -> HashMap<String, String> {
+    if let Ok(s) = env::var("GIT_CONFIG_PARAMETERS") {
+        parse_config_from_env_var_value(&s)
+    } else {
+        HashMap::new()
+    }
+}
+
+lazy_static! {
+    static ref GIT_CONFIG_PARAMETERS_REGEX: Regex =
+        Regex::new(r"'(delta\.[a-z-]+)=([^']+)'").unwrap();
+}
+
+fn parse_config_from_env_var_value(s: &str) -> HashMap<String, String> {
+    GIT_CONFIG_PARAMETERS_REGEX
+        .captures_iter(s)
+        .map(|captures| (captures[1].to_string(), captures[2].to_string()))
+        .collect()
+}
+
+pub trait GitConfigGet {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self>
+    where
+        Self: Sized;
+}
+
+impl GitConfigGet for String {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        match git_config.config_from_env_var.get(key) {
+            Some(val) => Some(val.to_string()),
+            None => git_config.config.get_string(key).ok(),
+        }
+    }
+}
+
+impl GitConfigGet for Option<String> {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        match git_config.config_from_env_var.get(key) {
+            Some(val) => Some(Some(val.to_string())),
+            None => match git_config.config.get_string(key) {
+                Ok(val) => Some(Some(val)),
+                _ => None,
+            },
+        }
+    }
+}
+
+impl GitConfigGet for bool {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        match git_config.config_from_env_var.get(key).map(|s| s.as_str()) {
+            Some("true") => Some(true),
+            Some("false") => Some(false),
+            _ => git_config.config.get_bool(key).ok(),
+        }
+    }
+}
+
+impl GitConfigGet for usize {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        if let Some(s) = git_config.config_from_env_var.get(key) {
+            if let Ok(n) = s.parse::<usize>() {
+                return Some(n);
+            }
+        }
+        match git_config.config.get_i64(key) {
+            Ok(value) => Some(value as usize),
+            _ => None,
+        }
+    }
+}
+
+impl GitConfigGet for f64 {
+    fn git_config_get(key: &str, git_config: &GitConfig) -> Option<Self> {
+        if let Some(s) = git_config.config_from_env_var.get(key) {
+            if let Ok(n) = s.parse::<f64>() {
+                return Some(n);
+            }
+        }
+        match git_config.config.get_string(key) {
+            Ok(value) => value.parse::<f64>().ok(),
+            _ => None,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::parse_config_from_env_var_value;
+
+    #[test]
+    fn test_parse_config_from_env_var_value() {
+        // To generate test cases, use git -c ... with
+        // [core]
+        //     pager = env | grep GIT_CONFIG_PARAMETERS
+
+        let config = parse_config_from_env_var_value("'user.name=xxx'");
+        assert!(config.is_empty());
+
+        let config = parse_config_from_env_var_value("'delta.plus-style=green'");
+        assert_eq!(config["delta.plus-style"], "green");
+
+        let config = parse_config_from_env_var_value(
+            r##"'user.name=xxx' 'delta.hunk-header-line-number-style=red "#067a00"'"##,
+        );
+        assert_eq!(
+            config["delta.hunk-header-line-number-style"],
+            r##"red "#067a00""##
+        );
+
+        let config =
+            parse_config_from_env_var_value(r##"'user.name=xxx' 'delta.side-by-side=false'"##);
+        assert_eq!(config["delta.side-by-side"], "false");
+
+        let config = parse_config_from_env_var_value(
+            r##"'delta.plus-style=green' 'delta.side-by-side=false' 'delta.hunk-header-line-number-style=red "#067a00"'"##,
+        );
+        assert_eq!(config["delta.plus-style"], "green");
+        assert_eq!(config["delta.side-by-side"], "false");
+        assert_eq!(
+            config["delta.hunk-header-line-number-style"],
+            r##"red "#067a00""##
+        );
+    }
+}
diff --git a/src/options/get.rs b/src/options/get.rs
index e29b8cdf..a36987ca 100644
--- a/src/options/get.rs
+++ b/src/options/get.rs
@@ -109,3 +109,170 @@ impl GetOptionValue for String {}
 impl GetOptionValue for bool {}
 impl GetOptionValue for f64 {}
 impl GetOptionValue for usize {}
+
+#[cfg(test)]
+pub mod tests {
+    use std::env;
+    use std::fs::remove_file;
+
+    use crate::tests::integration_test_utils::integration_test_utils;
+
+    // TODO: the followig tests are collapsed into one since they all set the same env var and thus
+    // could affect each other if allowed to run concurrently.
+
+    #[test]
+    fn test_env_var_overrides_git_config() {
+        // ----------------------------------------------------------------------------------------
+        // simple string
+        let git_config_contents = b"
+[delta]
+    plus-style = blue
+";
+        let git_config_path = "delta__test_simple_string_env_var_overrides_git_config.gitconfig";
+
+        let opt = integration_test_utils::make_options_from_args_and_git_config(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.plus_style, "blue");
+
+        env::set_var("GIT_CONFIG_PARAMETERS", "'delta.plus-style=green'");
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.plus_style, "green");
+
+        remove_file(git_config_path).unwrap();
+
+        // ----------------------------------------------------------------------------------------
+        // complex string
+        let git_config_contents = br##"
+[delta]
+    minus-style = red bold ul "#ffeeee"
+"##;
+        let git_config_path = "delta__test_complex_string_env_var_overrides_git_config.gitconfig";
+
+        let opt = integration_test_utils::make_options_from_args_and_git_config(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.minus_style, r##"red bold ul #ffeeee"##);
+
+        env::set_var(
+            "GIT_CONFIG_PARAMETERS",
+            r##"'delta.minus-style=magenta italic ol "#aabbcc"'"##,
+        );
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.minus_style, r##"magenta italic ol "#aabbcc""##,);
+
+        remove_file(git_config_path).unwrap();
+
+        // ----------------------------------------------------------------------------------------
+        // option string
+        let git_config_contents = b"
+[delta]
+    plus-style = blue
+";
+        let git_config_path = "delta__test_option_string_env_var_overrides_git_config.gitconfig";
+
+        let opt = integration_test_utils::make_options_from_args_and_git_config(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.plus_style, "blue");
+
+        env::set_var("GIT_CONFIG_PARAMETERS", "'delta.plus-style=green'");
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.plus_style, "green");
+
+        remove_file(git_config_path).unwrap();
+
+        // ----------------------------------------------------------------------------------------
+        // bool
+        let git_config_contents = b"
+[delta]
+    side-by-side = true
+";
+        let git_config_path = "delta__test_bool_env_var_overrides_git_config.gitconfig";
+
+        let opt = integration_test_utils::make_options_from_args_and_git_config(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.side_by_side, true);
+
+        env::set_var("GIT_CONFIG_PARAMETERS", "'delta.side-by-side=false'");
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.side_by_side, false);
+
+        remove_file(git_config_path).unwrap();
+
+        // ----------------------------------------------------------------------------------------
+        // int
+        let git_config_contents = b"
+[delta]
+    max-line-length = 1
+";
+        let git_config_path = "delta__test_int_env_var_overrides_git_config.gitconfig";
+
+        let opt = integration_test_utils::make_options_from_args_and_git_config(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.max_line_length, 1);
+
+        env::set_var("GIT_CONFIG_PARAMETERS", "'delta.max-line-length=2'");
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.max_line_length, 2);
+
+        remove_file(git_config_path).unwrap();
+
+        // ----------------------------------------------------------------------------------------
+        // float
+        let git_config_contents = b"
+[delta]
+    max-line-distance = 0.6
+";
+        let git_config_path = "delta__test_float_env_var_overrides_git_config.gitconfig";
+
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.max_line_distance, 0.6);
+
+        env::set_var("GIT_CONFIG_PARAMETERS", "'delta.max-line-distance=0.7'");
+        let opt = integration_test_utils::make_options_from_args_and_git_config_honoring_env_var(
+            &[],
+            Some(git_config_contents),
+            Some(git_config_path),
+        );
+        assert_eq!(opt.max_line_distance, 0.7);
+
+        remove_file(git_config_path).unwrap();
+    }
+}
diff --git a/src/tests/integration_test_utils.rs b/src/tests/integration_test_utils.rs
index 37ae0575..8eb36748 100644
--- a/src/tests/integration_test_utils.rs
+++ b/src/tests/integration_test_utils.rs
@@ -18,11 +18,28 @@ pub mod integration_test_utils {
         git_config_contents: Option<&[u8]>,
         git_config_path: Option<&str>,
     ) -> cli::Opt {
+        _make_options_from_args_and_git_config(args, git_config_contents, git_config_path, false)
+    }
+
+    pub fn make_options_from_args_and_git_config_honoring_env_var(
+        args: &[&str],
+        git_config_contents: Option<&[u8]>,
+        git_config_path: Option<&str>,
+    ) -> cli::Opt {
+        _make_options_from_args_and_git_config(args, git_config_contents, git_config_path, true)
+    }
+
+    fn _make_options_from_args_and_git_config(
+        args: &[&str],
+        git_config_contents: Option<&[u8]>,
+        git_config_path: Option<&str>,
+        honor_env_var: bool,
+    ) -> cli::Opt {
         let mut args: Vec<&str> = itertools::chain(&["/dev/null", "/dev/null"], args)
             .map(|s| *s)
             .collect();
         let mut git_config = match (git_config_contents, git_config_path) {
-            (Some(contents), Some(path)) => Some(make_git_config(contents, path)),
+            (Some(contents), Some(path)) => Some(make_git_config(contents, path, honor_env_var)),
             _ => {
                 args.push("--no-gitconfig");
                 None
@@ -52,11 +69,11 @@ pub mod integration_test_utils {
         config::Config::from(make_options_from_args(args))
     }
 
-    fn make_git_config(contents: &[u8], path: &str) -> GitConfig {
+    fn make_git_config(contents: &[u8], path: &str, honor_env_var: bool) -> GitConfig {
         let path = Path::new(path);
         let mut file = File::create(path).unwrap();
         file.write_all(contents).unwrap();
-        GitConfig::from_path(&path)
+        GitConfig::from_path(&path, honor_env_var)
     }
 
     pub fn get_line_of_code_from_delta(