Add tools/src format check

Adds a presubmit check to //tools/src to enforce that the Go code is
properly formatted.

Bug: chromium:343519239
Change-Id: I84b7c64486971c5194a4fbfc5d889c24d5aef0c0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/190564
Reviewed-by: Austin Eng <[email protected]>
Commit-Queue: Brian Sheedy <[email protected]>
Auto-Submit: Brian Sheedy <[email protected]>
Commit-Queue: Austin Eng <[email protected]>

go_presubmit_support.py

@@ -26,23 +26,56 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
+def go_bin_path(input_api):
+    return input_api.os_path.join(input_api.change.RepositoryRoot(), 'tools',
+                                  'golang', 'bin')
+
+
 def go_path(input_api):
-    go = input_api.os_path.join(input_api.change.RepositoryRoot(), "tools",
-                                "golang", "bin", "go")
+    go = input_api.os_path.join(go_bin_path(input_api), 'go')
     if input_api.is_windows:
         go += '.exe'
 
     return go
 
 
+def gofmt_path(input_api):
+    gofmt = input_api.os_path.join(go_bin_path(input_api), 'gofmt')
+    if input_api.is_windows:
+        go += '.exe'
+    return gofmt
+
+
 def RunGoTests(input_api, output_api):
     results = []
     try:
         input_api.subprocess.check_call_out(
-            [go_path(input_api), "test", "./..."],
+            [go_path(input_api), 'test', './...'],
             stdout=input_api.subprocess.PIPE,
             stderr=input_api.subprocess.PIPE,
             cwd=input_api.PresubmitLocalPath())
     except input_api.subprocess.CalledProcessError as e:
         results.append(output_api.PresubmitError('%s' % (e, )))
     return results
+
+
+def EnforceGoFormatting(path, input_api, output_api):
+    errors = []
+    try:
+        stdout, _ = input_api.subprocess.check_call_out(
+            [gofmt_path(input_api), '-l', path],
+            stdout=input_api.subprocess.PIPE,
+            stderr=input_api.subprocess.STDOUT,
+            cwd=input_api.PresubmitLocalPath(),
+            text=True)
+        stdout = stdout.strip()
+        if stdout:
+            full_path = input_api.os_path.join(input_api.PresubmitLocalPath(),
+                                               path)
+            errors.append(
+                output_api.PresubmitError(
+                    'Go code in %s is not formatted, please run "gofmt -w %s"'
+                    % (path, full_path)))
+    except input_api.subprocess.CalledProcessError as e:
+        errors.append(output_api.PresubmitError('EnforceGoFormatting: %s' % e))
+    return errors

tools/PRESUBMIT.py

@@ -31,9 +31,13 @@
 def _DoCommonChecks(input_api, output_api):
     sys.path += [input_api.change.RepositoryRoot()]
 
-    from go_presubmit_support import RunGoTests
+    import go_presubmit_support
 
-    return RunGoTests(input_api, output_api)
+    results = go_presubmit_support.RunGoTests(input_api, output_api)
+    results.extend(
+        go_presubmit_support.EnforceGoFormatting('src', input_api, output_api))
+
+    return results
 
 
 CheckChangeOnUpload = _DoCommonChecks