From 75f33bd4230eb563241adba1e44952d632022cd9 Mon Sep 17 00:00:00 2001
From: Miles Johnson <milesj@users.noreply.github.com>
Date: Mon, 4 Jul 2022 23:52:16 -0700
Subject: [PATCH] ci: Use base/head from GH environment. (#180)

* Use env vars.

* Fix git.

* Try again.

* Try github context.

* Prepend head with prefix.

* Fix unexpected rev.
---
 .github/workflows/moon.yml                    |  2 +-
 .../src/actions/target/hasher.rs              |  5 ++--
 crates/vcs/src/git.rs                         | 29 ++++++++++++++-----
 packages/cli/CHANGELOG.md                     |  2 ++
 4 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/moon.yml b/.github/workflows/moon.yml
index 1a9d4c37a8c..af312ee7366 100644
--- a/.github/workflows/moon.yml
+++ b/.github/workflows/moon.yml
@@ -60,4 +60,4 @@ jobs:
       - uses: actions-rs/cargo@v1
         with:
           command: run
-          args: -- --color --log trace ci
+          args: -- --color --log trace ci --base ${{ github.base_ref || 'master' }}
diff --git a/crates/action-runner/src/actions/target/hasher.rs b/crates/action-runner/src/actions/target/hasher.rs
index d6734574c3e..1a7a3a5ad4f 100644
--- a/crates/action-runner/src/actions/target/hasher.rs
+++ b/crates/action-runner/src/actions/target/hasher.rs
@@ -67,9 +67,10 @@ pub async fn create_target_hasher(
     // For input files, hash them with the vcs layer first
     if !task.input_paths.is_empty() {
         let files = convert_paths_to_strings(&task.input_paths, &workspace.root)?;
-        let hashed_files = vcs.get_file_hashes(&files).await?;
 
-        hasher.hash_inputs(hashed_files);
+        if !files.is_empty() {
+            hasher.hash_inputs(vcs.get_file_hashes(&files).await?);
+        }
     }
 
     // For input globs, it's much more performant to:
diff --git a/crates/vcs/src/git.rs b/crates/vcs/src/git.rs
index 64124b11c85..77569e6d466 100644
--- a/crates/vcs/src/git.rs
+++ b/crates/vcs/src/git.rs
@@ -2,8 +2,8 @@ use crate::errors::VcsError;
 use crate::vcs::{TouchedFiles, Vcs, VcsResult};
 use async_trait::async_trait;
 use ignore::gitignore::{Gitignore, GitignoreBuilder};
-use moon_utils::fs;
 use moon_utils::process::{output_to_string, output_to_trimmed_string, Command};
+use moon_utils::{fs, string_vec};
 use regex::Regex;
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::path::{Path, PathBuf};
@@ -41,24 +41,38 @@ impl Git {
     }
 
     async fn get_merge_base(&self, base: &str, head: &str) -> VcsResult<String> {
-        let candidates = [
+        let mut args = string_vec!["merge-base", head];
+
+        // To start, we need to find a working base origin
+        for candidate in [
             base.to_owned(),
             format!("origin/{}", base),
             format!("upstream/{}", base),
-        ];
-
-        for candidate in candidates {
-            if let Ok(hash) = self
+        ] {
+            if self
                 .run_command(
                     &mut self.create_command(vec!["merge-base", &candidate, head]),
                     true,
                 )
                 .await
+                .is_ok()
             {
-                return Ok(hash);
+                args.push(candidate.clone());
             }
         }
 
+        // Then we need to run it again and extract the base hash using the found origins
+        // This is necessary to support comparisons between forks!
+        if let Ok(hash) = self
+            .run_command(
+                &mut self.create_command(args.iter().map(|a| a.as_str()).collect()),
+                true,
+            )
+            .await
+        {
+            return Ok(hash);
+        }
+
         Ok(base.to_owned())
     }
 
@@ -322,7 +336,6 @@ impl Vcs for Git {
                     // are displayed as-is and are not quoted/escaped
                     "-z",
                     &base,
-                    revision,
                 ]),
                 false,
             )
diff --git a/packages/cli/CHANGELOG.md b/packages/cli/CHANGELOG.md
index c6ee6520f03..59b677acb68 100644
--- a/packages/cli/CHANGELOG.md
+++ b/packages/cli/CHANGELOG.md
@@ -14,6 +14,8 @@
 #### 🐞 Fixes
 
 - Fixed an issue with a globally installed moon not being executable in PowerShell.
+- Fixed an issue with empty files being passed to `git hash-object`.
+- Fixed an issue where a `git merge-base` could not be resolved when base and head are provided.
 
 #### ⚙️ Internal