cmd/go: invalidate cached test results when the -timeout flag changes

Fixes #36134

Change-Id: Icc5e1269696db778ba5c1e6bebed9969b8841c81
Reviewed-on: https://go-review.googlesource.com/c/go/+/220365
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>

doc/go1.15.html

@@ -47,6 +47,14 @@ TODO
 TODO
 </p>
 
+<h4 id="go-test"><code>go</code> <code>test</code></h4>
+
+<p><!-- https://golang.org/issue/36134 -->
+  Changing the <code>-timeout</code> flag now invalidates cached test results. A
+  cached result for a test run with a long timeout will no longer count as
+  passing when <code>go</code> <code>test</code> is re-invoked with a short one.
+</p>
+
 <h4 id="go-flag-parsing">Flag parsing</h4>
 
 <p><!-- https://golang.org/cl/211358 -->

src/cmd/go/go_test.go

@@ -2431,30 +2431,6 @@ func TestTestCache(t *testing.T) {
 	tg.setenv("GOPATH", tg.tempdir)
 	tg.setenv("GOCACHE", tg.path("cache"))
 
-	if runtime.Compiler != "gccgo" {
-		// timeout here should not affect result being cached
-		// or being retrieved later.
-		tg.run("test", "-x", "-timeout=10s", "errors")
-		tg.grepStderr(`[\\/]compile|gccgo`, "did not run compiler")
-		tg.grepStderr(`[\\/]link|gccgo`, "did not run linker")
-		tg.grepStderr(`errors\.test`, "did not run test")
-
-		tg.run("test", "-x", "errors")
-		tg.grepStdout(`ok  \terrors\t\(cached\)`, "did not report cached result")
-		tg.grepStderrNot(`[\\/]compile|gccgo`, "incorrectly ran compiler")
-		tg.grepStderrNot(`[\\/]link|gccgo`, "incorrectly ran linker")
-		tg.grepStderrNot(`errors\.test`, "incorrectly ran test")
-		tg.grepStderrNot("DO NOT USE", "poisoned action status leaked")
-
-		// Even very low timeouts do not disqualify cached entries.
-		tg.run("test", "-timeout=1ns", "-x", "errors")
-		tg.grepStderrNot(`errors\.test`, "incorrectly ran test")
-
-		tg.run("clean", "-testcache")
-		tg.run("test", "-x", "errors")
-		tg.grepStderr(`errors\.test`, "did not run test")
-	}
-
 	// The -p=1 in the commands below just makes the -x output easier to read.
 
 	t.Log("\n\nINITIAL\n\n")

src/cmd/go/internal/test/test.go

@@ -1291,16 +1291,13 @@ func (c *runCache) tryCacheWithID(b *work.Builder, a *work.Action, id string) bo
 			"-test.parallel",
 			"-test.run",
 			"-test.short",
+			"-test.timeout",
 			"-test.v":
 			// These are cacheable.
 			// Note that this list is documented above,
 			// so if you add to this list, update the docs too.
 			cacheArgs = append(cacheArgs, arg)
 
-		case "-test.timeout":
-			// Special case: this is cacheable but ignored during the hash.
-			// Do not add to cacheArgs.
-
 		default:
 			// nothing else is cacheable
 			if cache.DebugTest {

src/cmd/go/testdata/script/test_cache_inputs.txt

@@ -29,6 +29,23 @@ go test testcache -run=TestLookupEnv
 go test testcache -run=TestLookupEnv
 stdout '\(cached\)'
 
+# Changes in arguments forwarded to the test should invalidate cached test
+# results.
+go test testcache -run=TestOSArgs -v hello
+! stdout '\(cached\)'
+stdout 'hello'
+go test testcache -run=TestOSArgs -v goodbye
+! stdout '\(cached\)'
+stdout 'goodbye'
+
+# golang.org/issue/36134: that includes the `-timeout` argument.
+go test testcache -run=TestOSArgs -timeout=20m -v
+! stdout '\(cached\)'
+stdout '-test\.timeout[= ]20m'
+go test testcache -run=TestOSArgs -timeout=5s -v
+! stdout '\(cached\)'
+stdout '-test\.timeout[= ]5s'
+
 # If the test stats a file, changes to the file should invalidate the cache.
 go test testcache -run=FileSize
 go test testcache -run=FileSize
@@ -207,6 +224,10 @@ func TestExternalFile(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestOSArgs(t *testing.T) {
+	t.Log(os.Args)
+}
 -- mkold.go --
 package main