Add PRESUBMIT_COMMIT_MESSAGE to the env.

This will allow custom hooks to perform checks on the commit message
in addition to the content of changed files.

BUG: None

Change-Id: I70ab8a570e5436bb90f061e1cc3174ebc5654e6b

3 files changed, 5 insertions, 0 deletions

diff --git a/README.md b/README.md
index e6b8d0c..5862930 100644
--- a/README.md
+++ b/README.md
@@ -74,6 +74,7 @@ that is executed.
 my_first_hook = program --gogog ${PREUPLOAD_FILES}
 another_hook = funtimes --i-need "some space" ${PREUPLOAD_FILES}
 some_fish = linter --ate-a-cat ${PREUPLOAD_FILES}
+some_dog = tool --no-cat-in-commit-message ${PREUPLOAD_COMMIT_MESSAGE}
 ```
 
 ### `[Builtin Hooks]`
@@ -118,6 +119,7 @@ such will be expanded correctly via argument positions, so do not try to
 force your own quote handling.
 
 * `${PREUPLOAD_FILES}`: List of files to operate on.
+* `${PREUPLOAD_COMMIT_MESSAGE}`: Commit message.
 
 ```
 [Builtin Hooks Options]
diff --git a/pre-upload.py b/pre-upload.py
index e9bdfa2..6cb19b7 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -165,6 +165,7 @@ def _run_project_hooks(project_name, proj_dir=None,
         os.environ['PREUPLOAD_COMMIT'] = commit
         diff = rh.git.get_affected_files(commit)
         desc = rh.git.get_commit_desc(commit)
+        os.environ['PREUPLOAD_COMMIT_MESSAGE'] = desc
 
         results = []
         for hook in hooks:
diff --git a/rh/hooks.py b/rh/hooks.py
index 8979bf1..2b9960b 100644
--- a/rh/hooks.py
+++ b/rh/hooks.py
@@ -89,6 +89,8 @@ def _update_options(options, diff):
     for option in options:
         if option == '${PREUPLOAD_FILES}':
             ret.extend(x.file for x in diff if x.status != 'D')
+        elif option == '${PREUPLOAD_COMMIT_MESSAGE}':
+            ret.append(os.environ['PREUPLOAD_COMMIT_MESSAGE'])
         else:
             ret.append(option)
     return ret