rhg: read [paths] for `--repository` value

hg parses `-R` and `--repository` CLI arguments "early" in order to know which
local repository to load config from. (Config can then affect whether or how to
fall back.)

The value of of those arguments can be not only a filesystem path, but also an
alias configured in the `[paths]` section. This part was missing in rhg and
this patch implements that.

The current patch still lacks functionality to read config of current repository
if we are not at root of repo. That will be fixed in upcoming patches.

A new crate `home` is added to get path of home directory.

Differential Revision: https://phab.mercurial-scm.org/D10296

rust/Cargo.lock

@@ -831,6 +831,7 b' dependencies = ['
  "env_logger",
  "format-bytes",
  "hg-core",
+ "home",
  "lazy_static",
  "log",
  "micro-timer",

rust/hg-core/src/config.rs

@@ -12,5 +12,5 b''
 mod config;
 mod layer;
 mod values;
-pub use config::{Config, ConfigValueParseError};
+pub use config::{Config, ConfigSource, ConfigValueParseError};
 pub use layer::{ConfigError, ConfigParseError};

rust/hg-core/src/repo.rs

@@ -53,7 +53,7 b' impl Repo {'
     /// Having two methods would just move that `if` to almost all callers.
     pub fn find(
         config: &Config,
-        explicit_path: Option<&Path>,
+        explicit_path: Option<PathBuf>,
     ) -> Result<Self, RepoError> {
         if let Some(root) = explicit_path {
             if root.join(".hg").is_dir() {

rust/rhg/Cargo.toml

@@ -12,6 +12,7 b' hg-core = { path = "../hg-core"}'
 chrono = "0.4.19"
 clap = "2.33.1"
 derive_more = "0.99"
+home = "0.5.3"
 lazy_static = "1.4.0"
 log = "0.4.11"
 micro-timer = "0.3.1"

rust/rhg/src/main.rs

@@ -5,7 +5,7 b' use clap::AppSettings;'
 use clap::Arg;
 use clap::ArgMatches;
 use format_bytes::{format_bytes, join};
-use hg::config::Config;
+use hg::config::{Config, ConfigSource};
 use hg::repo::{Repo, RepoError};
 use hg::utils::files::{get_bytes_from_os_str, get_path_from_bytes};
 use hg::utils::SliceExt;
@@ -167,8 +167,74 b' fn main() {'
             )
         }
     }
-    let repo_path = early_args.repo.as_deref().map(get_path_from_bytes);
-    let repo_result = match Repo::find(&non_repo_config, repo_path) {
+    let repo_arg = early_args.repo.unwrap_or(Vec::new());
+    let repo_path: Option<PathBuf> = {
+        if repo_arg.is_empty() {
+            None
+        } else {
+            let local_config = {
+                if std::env::var_os("HGRCSKIPREPO").is_none() {
+                    let current_dir = hg::utils::current_dir();
+                    // TODO: handle errors from current_dir
+                    if let Ok(current_dir_path) = current_dir {
+                        let config_files = vec![
+                            ConfigSource::AbsPath(
+                                current_dir_path.join(".hg/hgrc"),
+                            ),
+                            ConfigSource::AbsPath(
+                                current_dir_path.join(".hg/hgrc-not-shared"),
+                            ),
+                        ];
+                        // TODO: handle errors from
+                        // `load_from_explicit_sources`
+                        Config::load_from_explicit_sources(config_files).ok()
+                    } else {
+                        None
+                    }
+                } else {
+                    None
+                }
+            };
+
+            let non_repo_config_val = {
+                let non_repo_val = non_repo_config.get(b"paths", &repo_arg);
+                match &non_repo_val {
+                    Some(val) if val.len() > 0 => home::home_dir()
+                        .unwrap_or_else(|| PathBuf::from("~"))
+                        .join(get_path_from_bytes(val))
+                        .canonicalize()
+                        // TODO: handle error and make it similar to python
+                        // implementation maybe?
+                        .ok(),
+                    _ => None,
+                }
+            };
+
+            let config_val = match &local_config {
+                None => non_repo_config_val,
+                Some(val) => {
+                    let local_config_val = val.get(b"paths", &repo_arg);
+                    match &local_config_val {
+                        Some(val) if val.len() > 0 => {
+                            // presence of a local_config assures that
+                            // current_dir
+                            // wont result in an Error
+                            let canpath = hg::utils::current_dir()
+                                .unwrap()
+                                .join(get_path_from_bytes(val))
+                                .canonicalize();
+                            canpath.ok().or(non_repo_config_val)
+                        }
+                        _ => non_repo_config_val,
+                    }
+                }
+            };
+            config_val.or(Some(get_path_from_bytes(&repo_arg).to_path_buf()))
+        }
+    };
+
+    let repo_result = match Repo::find(&non_repo_config, repo_path.to_owned())
+    {
         Ok(repo) => Ok(repo),
         Err(RepoError::NotFound { at }) if repo_path.is_none() => {
             // Not finding a repo is not fatal yet, if `-R` was not given

tests/test-globalopts.t

@@ -65,8 +65,6 b' Testing -R/--repository:'
 
 -R with path aliases:
 
-TODO: add rhg support for path aliases
-#if no-rhg
   $ cd c
   $ hg -R default identify
   8580ff50825a tip
@@ -81,7 +79,6 b' TODO: add rhg support for path aliases'
   $ HOME=`pwd`/../ hg -R relativetohome identify
   8580ff50825a tip
   $ cd ..
-#endif
 
 #if no-outer-repo