Add an option to ignore merged commits

When uploading merge-commits, git log will list commits that are not
necessarily uploaded (since they have usually been already committed to
another branch). In order to avoid developers skipping verification on
these cases, this change adds an option to the config file that will add
--first-parent to the git log invocation, so pre-upload checks are only
performed on the commits that the developer intended.

Bug: 31926893
Test: repo upload
Change-Id: I76959906ed05b5cd09c4263fb54997b55dd6cfc3

1 files changed, 22 insertions, 0 deletions

diff --git a/rh/config.py b/rh/config.py
index 05d7cb2..6a149d7 100644
--- a/rh/config.py
+++ b/rh/config.py
@@ -97,6 +97,10 @@ class PreSubmitConfig(object):
     BUILTIN_HOOKS_SECTION = 'Builtin Hooks'
     BUILTIN_HOOKS_OPTIONS_SECTION = 'Builtin Hooks Options'
     TOOL_PATHS_SECTION = 'Tool Paths'
+    OPTIONS_SECTION = 'Options'
+
+    OPTION_IGNORE_MERGED_COMMITS = 'ignore_merged_commits'
+    VALID_OPTIONS = (OPTION_IGNORE_MERGED_COMMITS,)
 
     def __init__(self, paths=('',), global_paths=()):
         """Initialize.
@@ -168,6 +172,14 @@ class PreSubmitConfig(object):
             yield (hook, functools.partial(rh.hooks.BUILTIN_HOOKS[hook],
                                            options=options))
 
+    @property
+    def ignore_merged_commits(self):
+        """Whether to skip hooks for merged commits."""
+        return rh.shell.boolean_shell_value(
+            self.config.get(self.OPTIONS_SECTION,
+                            self.OPTION_IGNORE_MERGED_COMMITS, None),
+            False)
+
     def _validate(self):
         """Run consistency checks on the config settings."""
         config = self.config
@@ -178,6 +190,7 @@ class PreSubmitConfig(object):
             self.BUILTIN_HOOKS_SECTION,
             self.BUILTIN_HOOKS_OPTIONS_SECTION,
             self.TOOL_PATHS_SECTION,
+            self.OPTIONS_SECTION,
         ))
         bad_sections = set(config.sections()) - valid_sections
         if bad_sections:
@@ -233,3 +246,12 @@ class PreSubmitConfig(object):
             if bad_tools:
                 raise ValidationError('%s: unknown tools: %s' %
                                       (self.paths, bad_tools))
+
+        # Reject unknown options.
+        valid_options = set(self.VALID_OPTIONS)
+        if config.has_section(self.OPTIONS_SECTION):
+            options = set(config.options(self.OPTIONS_SECTION))
+            bad_options = options - valid_options
+            if bad_options:
+                raise ValidationError('%s: unknown options: %s' %
+                                      (self.paths, bad_options))