Merge "Show bazel help for b called without args." am: bb53fe394b

Original change: https://android-review.googlesource.com/c/platform/build/+/1737501

Change-Id: I973fe2c359649067c115c9af0ed1b1935e1807d0

envsetup.sh

@@ -1696,12 +1696,19 @@ function _trigger_build()
     fi
 )
 
+# Convenience entry point (like m) to use Bazel in AOSP.
 function b()
 (
     # Generate BUILD, bzl files into the synthetic Bazel workspace (out/soong/workspace).
     m nothing GENERATE_BAZEL_FILES=true || return 1
     # Then, run Bazel using the synthetic workspace as the --package_path.
+    if [[ -z "$@" ]]; then
+        # If there are no args, show help.
+        "$(gettop)/tools/bazel" help
+    else
+        # Else, always run with the bp2build configuration, which sets Bazel's package path to the synthetic workspace.
         "$(gettop)/tools/bazel" "$@" --config=bp2build
+    fi
 )
 
 function m()