Cannot use generated `pgoprofile` with coverdata

[EtiennePerot]

I am trying to specify pgoprofile in a go_binary that (recursively) depends on @io_bazel_rules_go//go/tools/coverdata. The pgoprofile is a label that points to a generated file. This runs into the following error:

ERROR: .../BUILD:8:11: in go_library rule [...]:
Traceback (most recent call last):
        File "[...]/io_bazel_rules_go/go/private/rules/library.bzl", line 40, column 25, in _go_library_impl
                archive = go.archive(go, source)
        File "[...]/io_bazel_rules_go/go/private/actions/archive.bzl", line 77, column 17, in emit_archive
                fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
Error in fail: Archive mode does not match @io_bazel_rules_go//go/tools/coverdata:coverdata is linux_amd64_pure_stripped expected linux_amd64_pure_stripped

I added the following debug messages just above the fail in go/private/actions/archive.bzl's emit_archive to see what was going on:

    files = []
    for a in direct:
        files.append(a.runfiles)
        if a.source.mode != go.mode:
            print("amd64: {} vs {}: eq={}", a.source.mode.amd64, go.mode.amd64, a.source.mode.amd64 == go.mode.amd64)
            print("arm: {} vs {}: eq={}", a.source.mode.arm, go.mode.arm, a.source.mode.arm == go.mode.arm)
            print("cover_format: {} vs {}: eq={}", a.source.mode.cover_format, go.mode.cover_format, a.source.mode.cover_format == go.mode.cover
_format)
            print("debug: {} vs {}: eq={}", a.source.mode.debug, go.mode.debug, a.source.mode.debug == go.mode.debug)
            print("gc_goopts: {} vs {}: eq={}", a.source.mode.gc_goopts, go.mode.gc_goopts, a.source.mode.gc_goopts == go.mode.gc_goopts)
            print("gc_linkopts: {} vs {}: eq={}", a.source.mode.gc_linkopts, go.mode.gc_linkopts, a.source.mode.gc_linkopts == go.mode.gc_linkop
ts)
            print("goarch: {} vs {}: eq={}", a.source.mode.goarch, go.mode.goarch, a.source.mode.goarch == go.mode.goarch)
            print("goos: {} vs {}: eq={}", a.source.mode.goos, go.mode.goos, a.source.mode.goos == go.mode.goos)
            print("link: {} vs {}: eq={}", a.source.mode.link, go.mode.link, a.source.mode.link == go.mode.link)
            print("msan: {} vs {}: eq={}", a.source.mode.msan, go.mode.msan, a.source.mode.msan == go.mode.msan)
            print("pgoprofile: {} vs {}: eq={}", a.source.mode.pgoprofile, go.mode.pgoprofile, a.source.mode.pgoprofile == go.mode.pgoprofile)
            print("pure: {} vs {}: eq={}", a.source.mode.pure, go.mode.pure, a.source.mode.pure == go.mode.pure)
            print("race: {} vs {}: eq={}", a.source.mode.race, go.mode.race, a.source.mode.race == go.mode.race)
            print("stamp: {} vs {}: eq={}", a.source.mode.stamp, go.mode.stamp, a.source.mode.stamp == go.mode.stamp)
            print("static: {} vs {}: eq={}", a.source.mode.static, go.mode.static, a.source.mode.static == go.mode.static)
            print("strip: {} vs {}: eq={}", a.source.mode.strip, go.mode.strip, a.source.mode.strip == go.mode.strip)
            print("tags: {} vs {}: eq={}", a.source.mode.tags, go.mode.tags, a.source.mode.tags == go.mode.tags)
            fail("Archive mode does not match {} is {} expected {}".format(a.data.label, a.source.mode, go.mode))
    runfiles = runfiles.merge_all(files)

Which revealed that the mismatching field of mode was the pgoprofile field:

DEBUG: [...]/go/private/actions/archive.bzl:77:18: amd64: {} vs {}: eq={}   True
DEBUG: [...]/go/private/actions/archive.bzl:78:18: arm: {} vs {}: eq={}   True
DEBUG: [...]/go/private/actions/archive.bzl:79:18: cover_format: {} vs {}: eq={} lcov lcov True
DEBUG: [...]/go/private/actions/archive.bzl:80:18: debug: {} vs {}: eq={} False False True
DEBUG: [...]/go/private/actions/archive.bzl:81:18: gc_goopts: {} vs {}: eq={} [] [] True
DEBUG: [...]/go/private/actions/archive.bzl:82:18: gc_linkopts: {} vs {}: eq={} [] [] True
DEBUG: [...]/go/private/actions/archive.bzl:83:18: goarch: {} vs {}: eq={} amd64 amd64 True
DEBUG: [...]/go/private/actions/archive.bzl:84:18: goos: {} vs {}: eq={} linux linux True
DEBUG: [...]/go/private/actions/archive.bzl:85:18: link: {} vs {}: eq={} normal normal True
DEBUG: [...]/go/private/actions/archive.bzl:86:18: msan: {} vs {}: eq={} False False True
DEBUG: [...]/go/private/actions/archive.bzl:87:18: pgoprofile: {} vs {}: eq={} <generated file profile.pgo.pprof.pb> <generated file profile.pgo.pprof.pb> False
DEBUG: [...]/go/private/actions/archive.bzl:88:18: pure: {} vs {}: eq={} True True True
DEBUG: [...]/go/private/actions/archive.bzl:89:18: race: {} vs {}: eq={} False False True
DEBUG: [...]/go/private/actions/archive.bzl:90:18: stamp: {} vs {}: eq={} True True True
DEBUG: [...]/go/private/actions/archive.bzl:91:18: static: {} vs {}: eq={} False False True
DEBUG: [...]/go/private/actions/archive.bzl:92:18: strip: {} vs {}: eq={} True True True
DEBUG: [...]/go/private/actions/archive.bzl:93:18: tags: {} vs {}: eq={} ["pgo"] ["pgo"] True

... So I believe the check at

rules_go/go/private/actions/archive.bzl

Lines 82 to 83 in 5e3cb43

	if a.source.mode != go.mode:
	fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))

is failing because a.source.mode.pgoprofile and go.mode.pgoprofile are seen as different, even though they are the same auto-generated label.

Workarounds:

• Passing the PGO profile label as --@io_bazel_rules_go//go/config:pgoprofile works.
• Removing the dependency on @io_bazel_rules_go//go/tools/coverdata also works.

[EtiennePerot]

The following patch addresses the issue, but I am not sure if this would be an acceptable workaround. If so, let me know and I can send a PR.

diff --git a/go/private/actions/archive.bzl b/go/private/actions/archive.bzl
index 3bf0bffd..d71d3d34 100644
--- a/go/private/actions/archive.bzl
+++ b/go/private/actions/archive.bzl
@@ -73,7 +73,7 @@ def emit_archive(go, source = None, _recompile_suffix = "", recompile_internal_d
     files = []
     for a in direct:
         files.append(a.runfiles)
-        if a.source.mode != go.mode:
+        if a.source.mode != go.mode and a.source.mode.pgoprofile == None:
             fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
     runfiles = runfiles.merge_all(files)