support for --url for arbitrary urls when fetching (#450)

Also known as 'anonymous remotes'.

README.md

@@ -52,6 +52,7 @@ Please see _'Development Status'_ for a listing of all crates and their capabili
     * **remote**    
         * [x] **refs** - list all references available on the remote based on the current remote configuration.
         * [x] **ref-map** - show how remote references relate to their local tracking branches as mapped by refspecs.
+    * **fetch** - fetch the current remote or the given one, optionally just as dry-run.    
     * **credential**
         * [x] **fill/approve/reject** - The same as `git credential`, but implemented in Rust, calling helpers only when from trusted configuration.
     * **free** - no git repository necessary

gitoxide-core/src/repository/fetch.rs

@@ -6,6 +6,7 @@ pub struct Options {
     pub format: OutputFormat,
     pub dry_run: bool,
     pub remote: Option<String>,
+    pub url: Option<git::Url>,
     /// If non-empty, override all ref-specs otherwise configured in the remote
     pub ref_specs: Vec<BString>,
 }
@@ -26,9 +27,11 @@ pub(crate) mod function {
             format,
             dry_run,
             remote,
+            url,
             ref_specs,
         }: Options,
     ) -> anyhow::Result<()> {
+        let _remote = crate::repository::remote::by_name_or_url(&repo, remote.as_deref(), url)?;
         todo!()
     }
 }

gitoxide-core/src/repository/remote.rs

@@ -1,14 +1,14 @@
 #[cfg(any(feature = "blocking-client", feature = "async-client"))]
 mod refs_impl {
+    use super::by_name_or_url;
+    use crate::OutputFormat;
     use anyhow::bail;
     use git_repository as git;
     use git_repository::{
         protocol::fetch,
         refspec::{match_group::validate::Fix, RefSpec},
     };
 
-    use crate::OutputFormat;
-
     pub mod refs {
         use git_repository::bstr::BString;
 
@@ -46,15 +46,7 @@ mod refs_impl {
         }: refs::Context,
     ) -> anyhow::Result<()> {
         use anyhow::Context;
-        let mut remote = match (name, url) {
-            (Some(name), None) => repo.find_remote(&name)?,
-            (None, None) => repo
-                .head()?
-                .into_remote(git::remote::Direction::Fetch)
-                .context("Cannot find a remote for unborn branch")??,
-            (None, Some(url)) => repo.remote_at(url)?,
-            (Some(_), Some(_)) => bail!("Must not set both the remote name and the url - they are mutually exclusive"),
-        };
+        let mut remote = by_name_or_url(&repo, name.as_deref(), url)?;
         if let refs::Kind::Tracking { ref_specs, .. } = &kind {
             if format != OutputFormat::Human {
                 bail!("JSON output isn't yet supported for listing ref-mappings.");
@@ -258,3 +250,22 @@ mod refs_impl {
 }
 #[cfg(any(feature = "blocking-client", feature = "async-client"))]
 pub use refs_impl::{refs, refs_fn as refs, JsonRef};
+
+use git_repository as git;
+
+pub(crate) fn by_name_or_url<'repo>(
+    repo: &'repo git::Repository,
+    name: Option<&str>,
+    url: Option<git::Url>,
+) -> anyhow::Result<git::Remote<'repo>> {
+    use anyhow::{bail, Context};
+    Ok(match (name, url) {
+        (Some(name), None) => repo.find_remote(&name)?,
+        (None, None) => repo
+            .head()?
+            .into_remote(git::remote::Direction::Fetch)
+            .context("Cannot find a remote for unborn branch")??,
+        (None, Some(url)) => repo.remote_at(url)?,
+        (Some(_), Some(_)) => bail!("Must not set both the remote name and the url - they are mutually exclusive"),
+    })
+}

src/plumbing/main.rs

@@ -118,12 +118,14 @@ pub fn main() -> Result<()> {
             dry_run,
             remote,
             ref_spec,
+            url,
         }) => {
             let opts = core::repository::fetch::Options {
                 format,
                 dry_run,
                 remote,
                 ref_specs: ref_spec,
+                url,
             };
             prepare_and_run(
                 "fetch",

src/plumbing/options/mod.rs

@@ -129,6 +129,10 @@ pub mod fetch {
         #[clap(long, short = 'r')]
         pub remote: Option<String>,
 
+        /// Connect directly to the given URL, forgoing any configuration from the repository.
+        #[clap(long, short = 'u', conflicts_with("remote"), parse(try_from_os_str = std::convert::TryFrom::try_from))]
+        pub url: Option<git::Url>,
+
         /// Override the built-in and configured ref-specs with one or more of the given ones.
         #[clap(parse(try_from_os_str = git::env::os_str_to_bstring))]
         pub ref_spec: Vec<git_repository::bstr::BString>,