From e803bed845228c49e5a5b10e1bb8f0af89b79b44 Mon Sep 17 00:00:00 2001
From: Aaron Bull Schaefer <aaron@elasticdog.com>
Date: Mon, 12 Aug 2024 09:39:35 -0700
Subject: [PATCH] config: expand tilde in ssh key filepaths

Add home directory expansion for SSH key filepaths. This allows the
`signing.key` configuration value to work more universally across both
Linux and macOS without requiring an absolute path.

This moved and renamed the previous `expand_git_path` function to a more
generic location, and the prior use was updated accordingly.
---
 CHANGELOG.md           |  3 +++
 cli/src/cli_util.rs    |  4 ++--
 cli/src/git_util.rs    | 10 ----------
 docs/config.md         |  2 +-
 lib/src/file_util.rs   | 10 ++++++++++
 lib/src/ssh_signing.rs |  4 ++--
 6 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0afa80c58b..31fb7f8094 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,9 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 * The following diff formats now include information about copies and moves:
   `--color-words`, `--summary`
 
+* A tilde (`~`) at the start of the path will now be expanded to the user's home
+  directory when configuring a `signing.key` for SSH commit signing.
+
 ### Fixed bugs
 
 ## [0.20.0] - 2024-08-07
diff --git a/cli/src/cli_util.rs b/cli/src/cli_util.rs
index 4771ddc7b8..bf27ff2f2d 100644
--- a/cli/src/cli_util.rs
+++ b/cli/src/cli_util.rs
@@ -73,7 +73,7 @@ use jj_lib::workspace::{
     default_working_copy_factories, LockedWorkspace, WorkingCopyFactories, Workspace,
     WorkspaceLoadError, WorkspaceLoader,
 };
-use jj_lib::{dag_walk, fileset, git, op_heads_store, op_walk, revset};
+use jj_lib::{dag_walk, file_util, fileset, git, op_heads_store, op_walk, revset};
 use once_cell::unsync::OnceCell;
 use tracing::instrument;
 use tracing_chrome::ChromeLayerBuilder;
@@ -806,7 +806,7 @@ impl WorkspaceCommandHelper {
             if let Some(value) = config.string("core.excludesFile") {
                 let path = str::from_utf8(&value)
                     .ok()
-                    .map(crate::git_util::expand_git_path)?;
+                    .map(file_util::expand_home_path)?;
                 // The configured path is usually absolute, but if it's relative,
                 // the "git" command would read the file at the work-tree directory.
                 Some(self.workspace_root().join(path))
diff --git a/cli/src/git_util.rs b/cli/src/git_util.rs
index 6642470cef..00f5383d9a 100644
--- a/cli/src/git_util.rs
+++ b/cli/src/git_util.rs
@@ -419,13 +419,3 @@ export or their "parent" branches."#,
     }
     Ok(())
 }
-
-/// Expands "~/" to "$HOME/" as Git seems to do for e.g. core.excludesFile.
-pub fn expand_git_path(path_str: &str) -> PathBuf {
-    if let Some(remainder) = path_str.strip_prefix("~/") {
-        if let Ok(home_dir_str) = std::env::var("HOME") {
-            return PathBuf::from(home_dir_str).join(remainder);
-        }
-    }
-    PathBuf::from(path_str)
-}
diff --git a/docs/config.md b/docs/config.md
index 5d2552004e..c0906b116b 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -784,7 +784,7 @@ sign-all = true
 backend = "ssh"
 key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGj+J6N6SO+4P8dOZqfR1oiay2yxhhHnagH52avUqw5h"
 ## You can also use a path instead of embedding the key
-# key = "/home/me/.ssh/id_for_signing.pub"
+# key = "~/.ssh/id_for_signing.pub"
 ```
 
 By default the ssh backend will look for a `ssh-keygen` binary on your path. If you want
diff --git a/lib/src/file_util.rs b/lib/src/file_util.rs
index 55b24e9aab..c55b80df8b 100644
--- a/lib/src/file_util.rs
+++ b/lib/src/file_util.rs
@@ -69,6 +69,16 @@ pub fn remove_dir_contents(dirname: &Path) -> Result<(), PathError> {
     Ok(())
 }
 
+/// Expands "~/" to "$HOME/".
+pub fn expand_home_path(path_str: &str) -> PathBuf {
+    if let Some(remainder) = path_str.strip_prefix("~/") {
+        if let Ok(home_dir_str) = std::env::var("HOME") {
+            return PathBuf::from(home_dir_str).join(remainder);
+        }
+    }
+    PathBuf::from(path_str)
+}
+
 /// Turns the given `to` path into relative path starting from the `from` path.
 ///
 /// Both `from` and `to` paths are supposed to be absolute and normalized in the
diff --git a/lib/src/ssh_signing.rs b/lib/src/ssh_signing.rs
index f514b940a6..a80fbaaa0b 100644
--- a/lib/src/ssh_signing.rs
+++ b/lib/src/ssh_signing.rs
@@ -81,8 +81,8 @@ fn run_command(command: &mut Command, stdin: &[u8]) -> SshResult<Vec<u8>> {
 fn ensure_key_as_file(key: &str) -> SshResult<Either<PathBuf, tempfile::TempPath>> {
     let is_inlined_ssh_key = key.starts_with("ssh-");
     if !is_inlined_ssh_key {
-        let key_path = Path::new(key);
-        return Ok(either::Left(key_path.to_path_buf()));
+        let key_path = crate::file_util::expand_home_path(key);
+        return Ok(either::Left(key_path));
     }
 
     let mut pub_key_file = tempfile::Builder::new()