Reduce golden test output. (#506)

Reduce golden test output to only actual changes, ignoring cases we
cannot identify.

We have almost all cases covered that we can. Time to simplify testing.

This speeds up testing on my machine from ~1:50mins to 7secs.

Author: Marcus Boerger

toolchain/internal/BUILD.bazel

@@ -36,17 +36,3 @@ diff_test(
     file1 = "llvm_distributions.golden.sel.txt",
     file2 = "llvm_distributions.sel.txt",
 )
-
-sh_test(
-    name = "llvm_distributions_select_no_error_test",
-    srcs = ["llvm_distributions_select_no_error_test.sh"],
-    data = [
-        "llvm_distributions.golden.sel.txt",
-        "llvm_distributions.sel.txt",
-    ],
-    target_compatible_with = select({
-        "@platforms//os:osx": [],
-        "@platforms//os:linux": [],
-        "//conditions:default": ["@platforms//:incompatible"],
-    }),
-)

toolchain/internal/llvm_distributions.bzl

@@ -786,23 +786,28 @@ def _get_llvm_version(rctx):
         )
     return llvm_version
 
-def _get_all_llvm_distributions(*, extra_llvm_distributions):
-    dists = {
-        basename: struct(
+def _get_all_llvm_distributions(*, llvm_distributions, extra_llvm_distributions, parsed_llvm_version):
+    distributions = {}
+    for basename, sha256 in llvm_distributions.items():
+        version = _distribution_version(basename)
+        if parsed_llvm_version and parsed_llvm_version != version:
+            continue
+        distributions[basename] = struct(
             distribution = basename,
             sha256 = sha256,
+            version = version,
         )
-        for basename, sha256 in _llvm_distributions.items()
-    }
     if extra_llvm_distributions:
-        dists = dists | {
-            _distribution_basename(dist): struct(
+        for dist, sha256 in extra_llvm_distributions.items():
+            version = _distribution_version(dist)
+            if parsed_llvm_version and parsed_llvm_version != version:
+                continue
+            distributions[_distribution_basename(dist)] = struct(
                 distribution = dist,
                 sha256 = sha256,
+                version = version,
             )
-            for dist, sha256 in extra_llvm_distributions.items()
-        }
-    return dists
+    return distributions
 
 _UBUNTU_NAMES = [
     "arch",
@@ -1093,7 +1098,11 @@ def _find_llvm_basename_or_error(llvm_version, all_llvm_distributions, host_info
 def _distribution_urls(rctx):
     """Return LLVM `urls`, `shha256` and `strip_prefix` for the given context."""
     llvm_version = _get_llvm_version(rctx)
-    all_llvm_distributions = _get_all_llvm_distributions(extra_llvm_distributions = rctx.attr.extra_llvm_distributions)
+    all_llvm_distributions = _get_all_llvm_distributions(
+        llvm_distributions = _llvm_distributions,
+        extra_llvm_distributions = rctx.attr.extra_llvm_distributions,
+        parsed_llvm_version = _parse_version(llvm_version),
+    )
     _, sha256, strip_prefix, _ = _key_attrs(rctx)
 
     if rctx.attr.distribution == "auto":
@@ -1145,17 +1154,18 @@ def _write_distributions_impl(ctx):
     verify that predicted distributions have been configured. Otherwise the
     algorithm could not know the hash value.
     """
-    all_llvm_distributions = _get_all_llvm_distributions(
-        # Inject version '0.0.0' that verifies additional behavior using `extra_llvm_distributions`.
-        extra_llvm_distributions = {
-            "LLVM-0.0.0-Linux-ARM64.tar.xz": "a6b8679be46bdaa383e0c7f13a473ca8f7a4f87233f2cc0e0a7ab19e1b6265e7",
-            "/foo/bar/LLVM-0.0.0-Linux-X64.tar.xz?xyz": "0a764a8ca521606532ca9ec4e5745c933b16b7d30f4701a47ee851d448fcdb74",
-            "http://server/foo/bar/LLVM-0.0.0-macOS-ARM64.tar.xz#xyz": "9da86f64a99f5ce9b679caf54e938736ca269c5e069d0c94ad08b995c5f25c16",
-            "http://server/foo/bar/LLVM-0.0.0-macOS-X64.tar.xz": "264f2f1e8b67f066749349ae8b4943d346cd44e099464164ef21b42a57663540",
-            "http://server/clang%2Bllvm-0.0.0-aarch64-pc-windows-msvc.tar.xz": "5916d93bf80e3ae504022cdd8cb8887be001f9b68a7a08bd268727e8d858afa4",
-            "http://server/path-to-file/clang%2Bllvm-0.0.0-x86_64-pc-windows-msvc.tar.xz#bla": "5916d93bf80e3ae504022cdd8cb8887be001f9b68a7a08bd268727e8d858afa4",
-        },
-    )
+    use_llvm_distributions = _llvm_distributions
+
+    # Inject version '0.0.0' that verifies additional behavior using `extra_llvm_distributions`.
+    extra_llvm_distributions = {
+        "LLVM-0.0.0-Linux-ARM64.tar.xz": "a6b8679be46bdaa383e0c7f13a473ca8f7a4f87233f2cc0e0a7ab19e1b6265e7",
+        "/foo/bar/LLVM-0.0.0-Linux-X64.tar.xz?xyz": "0a764a8ca521606532ca9ec4e5745c933b16b7d30f4701a47ee851d448fcdb74",
+        "http://server/foo/bar/LLVM-0.0.0-macOS-ARM64.tar.xz#xyz": "9da86f64a99f5ce9b679caf54e938736ca269c5e069d0c94ad08b995c5f25c16",
+        "http://server/foo/bar/LLVM-0.0.0-macOS-X64.tar.xz": "264f2f1e8b67f066749349ae8b4943d346cd44e099464164ef21b42a57663540",
+        "http://server/clang%2Bllvm-0.0.0-aarch64-pc-windows-msvc.tar.xz": "5916d93bf80e3ae504022cdd8cb8887be001f9b68a7a08bd268727e8d858afa4",
+        "http://server/path-to-file/clang%2Bllvm-0.0.0-x86_64-pc-windows-msvc.tar.xz#bla": "5916d93bf80e3ae504022cdd8cb8887be001f9b68a7a08bd268727e8d858afa4",
+    }
+
     arch_list = [
         "aarch64",
         "armv7a",
@@ -1181,7 +1191,6 @@ def _write_distributions_impl(ctx):
     dist_dict_list = {
         "linux": [
             # keep sorted
-            struct(name = "ibm-aix", version = "7.2"),
             struct(name = "amzn", version = ANY_VERSION),
             struct(name = "arch", version = ANY_VERSION),
             struct(name = "centos", version = "6"),
@@ -1196,6 +1205,7 @@ def _write_distributions_impl(ctx):
             struct(name = "freebsd", version = "11"),
             struct(name = "freebsd", version = "12"),
             struct(name = "freebsd", version = "13"),
+            struct(name = "ibm-aix", version = "7.2"),
             struct(name = "linuxmint", version = "18"),
             struct(name = "linuxmint", version = "19"),
             struct(name = "pc-solaris", version = "2.11"),
@@ -1228,7 +1238,7 @@ def _write_distributions_impl(ctx):
     MAX_VERSION = _parse_version("20.1.3")
     version_dict = {
         _distribution_version(basename): None
-        for basename in all_llvm_distributions.keys()
+        for basename in use_llvm_distributions.keys() + extra_llvm_distributions.keys()
     } | {
         _parse_version(v): None
         for v in _llvm_distributions_base_url.keys()
@@ -1244,8 +1254,8 @@ def _write_distributions_impl(ctx):
     # We keep track of versions in `not_found` and remove the ones we found.
     # So at the end all version that were not found remain, hence the name.
     not_found = {
-        basename: None
-        for basename in all_llvm_distributions.keys()
+        _distribution_basename(distribution): None
+        for distribution in use_llvm_distributions.keys() + extra_llvm_distributions.keys()
     }
 
     # While computing we add predicted versions that are not configured as True.
@@ -1257,6 +1267,11 @@ def _write_distributions_impl(ctx):
 
     # For all versions X arch X os check if we can compute the distribution.
     for version in versions:
+        all_llvm_distributions = _get_all_llvm_distributions(
+            llvm_distributions = use_llvm_distributions,
+            extra_llvm_distributions = extra_llvm_distributions,
+            parsed_llvm_version = version,
+        )
         for arch in arch_list:
             for os in os_list:
                 if version < MIN_VERSION:
@@ -1283,17 +1298,17 @@ def _write_distributions_impl(ctx):
                             all_llvm_distributions,
                             host_info,
                         )
+                        skip_output = False
                         if error:
                             if error.startswith("ERROR: No matching config could be found for version"):
-                                # Simplify test output:
-                                error = "ERROR: No version selected"
+                                skip_output = True
                         else:
                             if predicted.endswith(".exe"):
                                 error = "ERROR: Windows .exe is not supported: " + predicted
                             elif predicted not in all_llvm_distributions:
                                 error = "ERROR: Unavailable prediction: " + predicted
                             elif len(basenames) == 0:
-                                error = "ERROR: No version selected"
+                                skip_output = True
                             elif len(basenames) == 1:
                                 predicted = basenames[0]
                             else:
@@ -1302,14 +1317,15 @@ def _write_distributions_impl(ctx):
                                 arch_found = [arch for arch in arch_list if arch in predicted]
                                 if len(arch_found) == 1 and arch_found[0] not in arch_alias_dict.get(arch, [arch]):
                                     error = "ERROR: Bad arch selection: " + predicted
-                        select.append("{version}-{arch}-{os}/{dist_name}/{dist_version} -> {basename}".format(
-                            version = _version_string(version),
-                            arch = arch,
-                            os = os,
-                            dist_name = dist.name,
-                            dist_version = dist.version,
-                            basename = error or predicted,
-                        ))
+                        if not skip_output:
+                            select.append("{version}-{arch}-{os}/{dist_name}/{dist_version} -> {basename}".format(
+                                version = _version_string(version),
+                                arch = arch,
+                                os = os,
+                                dist_name = dist.name,
+                                dist_version = dist.version,
+                                basename = error or predicted,
+                            ))
                     if len(basenames) != 1:
                         if basenames:
                             dupes.append("dup: {version}-{arch}-{os}-{dist_name}-{dist_version} -> {count}".format(