Add auto-PR creation for remote repos in contracts

1 files changed, 94 insertions, 85 deletions

diff --git a/makima/src/daemon/storage/patch.rs b/makima/src/daemon/storage/patch.rs
index b374d15..05c45a3 100644
--- a/makima/src/daemon/storage/patch.rs
+++ b/makima/src/daemon/storage/patch.rs
@@ -161,6 +161,99 @@ pub async fn get_head_sha(worktree_path: &Path) -> Result<String, PatchError> {
     Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
 }
 
+/// Resolve the merge-base SHA for diffing against the main/master branch.
+///
+/// Tries in order:
+/// 1. Upstream tracking branch merge-base
+/// 2. Common branches: origin/main, origin/master, main, master
+/// 3. Fallback: HEAD~1
+///
+/// Returns `Err(PatchError::EmptyPatch)` if the merge-base equals HEAD (no diff).
+pub async fn get_merge_base_sha(worktree_path: &Path) -> Result<String, PatchError> {
+    // Try to get the upstream tracking branch
+    let upstream_result = Command::new("git")
+        .current_dir(worktree_path)
+        .args(["rev-parse", "--abbrev-ref", "--symbolic-full-name", "@{u}"])
+        .output()
+        .await;
+
+    let base = if let Ok(output) = upstream_result {
+        if output.status.success() {
+            let upstream = String::from_utf8_lossy(&output.stdout).trim().to_string();
+            // Get merge-base with upstream
+            let merge_base = Command::new("git")
+                .current_dir(worktree_path)
+                .args(["merge-base", "HEAD", &upstream])
+                .output()
+                .await;
+
+            if let Ok(mb_output) = merge_base {
+                if mb_output.status.success() {
+                    Some(
+                        String::from_utf8_lossy(&mb_output.stdout)
+                            .trim()
+                            .to_string(),
+                    )
+                } else {
+                    None
+                }
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    } else {
+        None
+    };
+
+    // Get current HEAD SHA for comparison
+    let head_sha = Command::new("git")
+        .current_dir(worktree_path)
+        .args(["rev-parse", "HEAD"])
+        .output()
+        .await
+        .ok()
+        .filter(|o| o.status.success())
+        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string());
+
+    // If we couldn't find upstream, try common default branches
+    let base = if base.is_none() {
+        let default_branches = ["origin/main", "origin/master", "main", "master"];
+        let mut found_base = None;
+
+        for branch in default_branches {
+            let merge_base = Command::new("git")
+                .current_dir(worktree_path)
+                .args(["merge-base", "HEAD", branch])
+                .output()
+                .await;
+
+            if let Ok(output) = merge_base {
+                if output.status.success() {
+                    let mb_sha = String::from_utf8_lossy(&output.stdout).trim().to_string();
+                    // Skip if merge-base equals HEAD (would result in empty diff)
+                    if head_sha.as_ref() != Some(&mb_sha) {
+                        found_base = Some(mb_sha);
+                        break;
+                    }
+                }
+            }
+        }
+        found_base
+    } else {
+        // Also check upstream base
+        if base.as_ref() == head_sha.as_ref() {
+            None
+        } else {
+            base
+        }
+    };
+
+    // If still nothing, fall back to HEAD~1
+    Ok(base.unwrap_or_else(|| "HEAD~1".to_string()))
+}
+
 /// Result of creating an export patch.
 #[derive(Debug, Clone)]
 pub struct ExportPatchResult {
@@ -192,91 +285,7 @@ pub async fn create_export_patch(
     // Determine the base SHA to diff against
     let resolved_base_sha = match base_sha {
         Some(sha) => sha.to_string(),
-        None => {
-            // Try to find the merge-base with the default branch
-            // First, try to get the upstream tracking branch
-            let upstream_result = Command::new("git")
-                .current_dir(worktree_path)
-                .args(["rev-parse", "--abbrev-ref", "--symbolic-full-name", "@{u}"])
-                .output()
-                .await;
-
-            let base = if let Ok(output) = upstream_result {
-                if output.status.success() {
-                    let upstream = String::from_utf8_lossy(&output.stdout).trim().to_string();
-                    // Get merge-base with upstream
-                    let merge_base = Command::new("git")
-                        .current_dir(worktree_path)
-                        .args(["merge-base", "HEAD", &upstream])
-                        .output()
-                        .await;
-
-                    if let Ok(mb_output) = merge_base {
-                        if mb_output.status.success() {
-                            Some(String::from_utf8_lossy(&mb_output.stdout).trim().to_string())
-                        } else {
-                            None
-                        }
-                    } else {
-                        None
-                    }
-                } else {
-                    None
-                }
-            } else {
-                None
-            };
-
-            // Get current HEAD SHA for comparison
-            let head_sha = Command::new("git")
-                .current_dir(worktree_path)
-                .args(["rev-parse", "HEAD"])
-                .output()
-                .await
-                .ok()
-                .filter(|o| o.status.success())
-                .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string());
-
-            // If we couldn't find upstream, try common default branches
-            let base = if base.is_none() {
-                let default_branches = ["origin/main", "origin/master", "main", "master"];
-                let mut found_base = None;
-
-                for branch in default_branches {
-                    let merge_base = Command::new("git")
-                        .current_dir(worktree_path)
-                        .args(["merge-base", "HEAD", branch])
-                        .output()
-                        .await;
-
-                    if let Ok(output) = merge_base {
-                        if output.status.success() {
-                            let mb_sha = String::from_utf8_lossy(&output.stdout).trim().to_string();
-                            // Skip if merge-base equals HEAD (would result in empty diff)
-                            if head_sha.as_ref() != Some(&mb_sha) {
-                                found_base = Some(mb_sha);
-                                break;
-                            }
-                        }
-                    }
-                }
-                found_base
-            } else {
-                // Also check upstream base
-                if base.as_ref() == head_sha.as_ref() {
-                    None
-                } else {
-                    base
-                }
-            };
-
-            // If still nothing, get the first commit or use HEAD~1
-            base.unwrap_or_else(|| {
-                // This will be used, but if HEAD~1 doesn't exist (only one commit),
-                // git diff will handle it gracefully
-                "HEAD~1".to_string()
-            })
-        }
+        None => get_merge_base_sha(worktree_path).await?,
     };
 
     // Get diff stats using --stat