cmd/go/testdata/script: consistently set GOCACHE in fuzz tests

The fuzzing cache for interesting inputs is shared across all
invocations of scripts by default. When 'go clean -fuzzcache' is called,
or fuzz targets in different scripts have the same names, we can get
race-y unexpected behavior.

Since there isn't a easy way to set just the fuzz cache directory (test
has the flag -test.fuzzcachedir, but it requires setting it on each call
to 'go test'), instead we just consistently set GOCACHE to point to a
directory in the WORK dir. As a byproduct this also prevents usage of a
shared build cache, so we see an increase in build time for these tests.

Updates #59062

Change-Id: Ie78f2943b94f3302c5bdf1f8a1e93b207853666a
Reviewed-on: https://go-review.googlesource.com/c/go/+/476755
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Roland Shoemaker <roland@golang.org>
Auto-Submit: Roland Shoemaker <roland@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

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

@@ -1,4 +1,6 @@
 [!fuzz] skip
+[short] skip
+env GOCACHE=$WORK/cache
 
 # Test that running a fuzz target that returns without failing or calling
 # f.Fuzz fails and causes a non-zero exit status.

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # Run chatty fuzz targets with an error.
 ! go test -v chatty_error_fuzz_test.go

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # Cleanup should run after F.Skip.
 go test -run=FuzzTargetSkip

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

@@ -4,10 +4,10 @@
 
 [short] skip
 [!fuzz-instrumented] skip
+env GOCACHE=$WORK/cache
 
 # TODO(#51484): enabled debugging info to help diagnose a deadlock in the fuzzer
 env GODEBUG=fuzzdebug=1
-go clean --fuzzcache
 ! go test -fuzz=FuzzCov -v
 ! stderr 'cov instrumentation working'
 

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # The fuzz function should be able to detect whether -timeout
 # was set with T.Deadline. Note there is no F.Deadline, and

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # This test checks that cached corpus loading properly handles duplicate entries (this can
 # happen when a f.Add value has a duplicate entry in the cached corpus.) Duplicate entries

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # There are no seed values, so 'go test' should finish quickly.
 go test
@@ -14,8 +15,6 @@ exec ./fuzz.test$GOEXE -test.timeout=3s -test.fuzz=FuzzFast -test.fuzztime=5s -t
 # Timeout should not cause inputs to be written as crashers.
 ! exists testdata/fuzz
 
-env GOCACHE=$WORK/tmp
-
 # When we use fuzztime with an "x" suffix, it runs a specific number of times.
 # This fuzz function creates a file with a unique name ($pid.$count) on each
 # run. We count the files to find the number of runs.

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

@@ -7,6 +7,7 @@
 # due to ^C and EOF errors which are more common. We don't report those.
 [short] skip
 [!fuzz] skip
+env GOCACHE=$WORK/cache
 
 # If the I/O error occurs before F.Fuzz is called, the coordinator should
 # stop the worker and say that.

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

@@ -1,12 +1,12 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # FuzzA attempts to cause the mutator to create duplicate inputs that generate
 # new coverage. Previously this would trigger a corner case when the fuzzer
 # had a execution limit, causing it to deadlock and sit in the coordinator
 # loop indefinitely, failing to exit once the limit had been exhausted.
 
-go clean --fuzzcache
 go test -fuzz=FuzzA -fuzztime=100x -parallel=1
 
 -- go.mod --

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

@@ -1,4 +1,6 @@
 [!fuzz] skip
+[short] skip
+env GOCACHE=$WORK/cache
 
 # Matches only fuzz targets to test.
 go test standalone_fuzz_test.go

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

@@ -4,6 +4,7 @@
 
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # With fuzzing disabled, multiple targets can be tested.
 go test ./...

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

@@ -6,6 +6,7 @@
 # to the seed corpus in testdata, and failing the next time the test is run.
 
 [short] skip
+env GOCACHE=$WORK/cache
 
 # Running the seed corpus for all of the targets should pass the first
 # time, since nothing in the seed corpus will cause a crash.

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

@@ -4,6 +4,7 @@
 # 'go test' exits non-zero and no crasher is recorded.
 
 [short] skip
+env GOCACHE=$WORK/cache
 
 ! go test -fuzz=FuzzReturn
 ! exists testdata

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

@@ -8,6 +8,7 @@
 # tests seed values and the worker tests mutated values on the fuzz target.
 
 [short] skip
+env GOCACHE=$WORK/cache
 
 go test -fuzz=FuzzA -fuzztime=100x -parallel=1 -log=fuzz
 go run check_logs.go fuzz fuzz.worker

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

@@ -6,6 +6,7 @@
 # to the coordinator.
 
 [short] skip
+env GOCACHE=$WORK/cache
 
 # Start fuzzing. The worker crashes after 100 iterations.
 # The fuzz function writes the crashing input to "want" before exiting.

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

@@ -3,6 +3,7 @@
 [GOOS:windows] skip
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # FuzzNonCrash sends itself a signal that does not appear to be a crash.
 # We should not save a crasher.

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 # When running seed inputs, T.Parallel should let multiple inputs run in
 # parallel.

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

@@ -1,5 +1,6 @@
 [!fuzz] skip
 [short] skip
+env GOCACHE=$WORK/cache
 
 go test -fuzz=FuzzA -fuzztime=100x fuzz_setenv_test.go
 

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

@@ -5,6 +5,7 @@
 [short] skip
 [!fuzz] skip
 [!race] skip
+env GOCACHE=$WORK/cache
 
 # Test with coverage instrumentation enabled (-fuzz) and race instrumentation
 # but without actually fuzzing the target (by using a non-matching pattern)