Add git.ssh-key-file setting. This allows opting into a custom SSH key

file, overriding the hardcoded defaults of ~/.ssh/id_ed25519_sk,
~/.ssh/id_ed25519, and ~/.ssh/id_rsa.

Author: dconeybe

cli/src/config-schema.json

@@ -390,6 +390,11 @@
                     "type": "string",
                     "description": "Path to the git executable",
                     "default": "git"
+                },
+                "ssh-key-file": {
+                    "type": "string",
+                    "description": "Path to SSH key file to use; by default, uses the following files in ~/.ssh: id_ed25519_sk, id_ed25519, id_rsa",
+                    "default": ""
                 }
             }
         },

cli/src/git_util.rs

@@ -311,7 +311,11 @@ pub fn with_remote_git_callbacks<T>(
             .map(|x| x as &mut dyn FnMut(&git::Progress));
         callbacks.sideband_progress =
             sideband_progress_callback.map(|x| x as &mut dyn FnMut(&[u8]));
-        let mut get_ssh_keys = get_ssh_keys; // Coerce to unit fn type
+        let mut get_ssh_keys: &mut dyn FnMut(&str) -> Vec<PathBuf> =
+            match &git_settings.ssh_key_file {
+                None => &mut get_ssh_keys, // Coerce to unit fn type
+                Some(ssh_key_file) => &mut |_: &str| -> Vec<PathBuf> { vec![ssh_key_file.clone()] },
+            };
         callbacks.get_ssh_keys = Some(&mut get_ssh_keys);
         let mut get_pw =
             |url: &str, _username: &str| pinentry_get_pw(url).or_else(|| terminal_get_pw(ui, url));

lib/src/settings.rs

@@ -61,6 +61,7 @@ pub struct GitSettings {
     pub abandon_unreachable_commits: bool,
     pub subprocess: bool,
     pub executable_path: PathBuf,
+    pub ssh_key_file: Option<PathBuf>,
 }
 
 impl GitSettings {
@@ -70,6 +71,17 @@ impl GitSettings {
             abandon_unreachable_commits: settings.get_bool("git.abandon-unreachable-commits")?,
             subprocess: settings.get_bool("git.subprocess")?,
             executable_path: settings.get("git.executable-path")?,
+            ssh_key_file: match settings.get_string("git.ssh-key-file") {
+                Ok(ssh_key_file) => {
+                    let trimmed_ssh_key_file = ssh_key_file.trim();
+                    if trimmed_ssh_key_file.is_empty() {
+                        None
+                    } else {
+                        Some(PathBuf::from(trimmed_ssh_key_file))
+                    }
+                }
+                Err(_) => None,
+            },
         })
     }
 }
@@ -81,6 +93,7 @@ impl Default for GitSettings {
             abandon_unreachable_commits: true,
             subprocess: false,
             executable_path: PathBuf::from("git"),
+            ssh_key_file: None,
         }
     }
 }