Fix tests on Go 1.12 (#207)

* Fix format error in tests

When running the tests on Go 1.12, we get the following error:

> ./search_test.go:27:4: Fatalf format %s has arg executedEntry of wrong type *github.com/go-ldap/ldap.Entry

This patch fixes this by using the correct format verb.

* Makefile: Clarify which Go version support the `-race` flag

This patch updates the comment for the `RACE_FLAG` variable, to
indicate which Go version it is supported on.

* Makefile: Test for Go versions using release tags

Go doesn't really provide a stable interface to get its version. `go
version` fails when using `tip`.

This patch adds version detection using the release tags list. This
list is populated with a tag for each release of Go.

See: https://github.com/golang/go/blob/go1.12/src/go/build/build.go#L295-L305

* Makefile: Use Go version to check for `go tool vet`

Instead of checking for `go tool vet` using `go tool -n vet`, use a
version test.

This makes the Makefile more readable, and will also make it easier to
change the behavior for newer versions of Go.

* Makefile: Fix `go vet` on Go version 1.12

Go version 1.12 does not allow `go vet` to be run through `go tool
vet`. Instead we must run `go vet`.

In addition the experimental `-shadow` option has been removed, so
that check is not executed when running `go vet`.

See: https://golang.org/doc/go1.12#vet

* Travis CI: Run tests on Go 1.12

This patch adds Go 1.12 to the test matrix.

Author: olavmrk

.travis.yml

@@ -9,6 +9,7 @@ go:
     - "1.9.x"
     - "1.10.x"
     - "1.11.x"
+    - "1.12.x"
     - tip
 
 git:

Makefile

@@ -1,15 +1,46 @@
 .PHONY: default install build test quicktest fmt vet lint 
 
-GO_VERSION := $(shell go version | cut -d' ' -f3 | cut -d. -f2)
+# List of all release tags "supported" by our current Go version
+# E.g. ":go1.1:go1.2:go1.3:go1.4:go1.5:go1.6:go1.7:go1.8:go1.9:go1.10:go1.11:go1.12:"
+GO_RELEASE_TAGS := $(shell go list -f ':{{join (context.ReleaseTags) ":"}}:' runtime)
 
-# Only use the `-race` flag on newer versions of Go
-IS_OLD_GO := $(shell test $(GO_VERSION) -le 2 && echo true)
-ifeq ($(IS_OLD_GO),true)
+# Only use the `-race` flag on newer versions of Go (version 1.3 and newer)
+ifeq (,$(findstring :go1.3:,$(GO_RELEASE_TAGS)))
 	RACE_FLAG :=
 else
 	RACE_FLAG := -race -cpu 1,2,4
 endif
 
+# Run `go vet` on Go 1.12 and newer. For Go 1.5-1.11, use `go tool vet`
+ifneq (,$(findstring :go1.12:,$(GO_RELEASE_TAGS)))
+	GO_VET := go vet \
+		-atomic \
+		-bool \
+		-copylocks \
+		-nilfunc \
+		-printf \
+		-rangeloops \
+		-unreachable \
+		-unsafeptr \
+		-unusedresult \
+		.
+else ifneq (,$(findstring :go1.5:,$(GO_RELEASE_TAGS)))
+	GO_VET := go tool vet \
+		-atomic \
+		-bool \
+		-copylocks \
+		-nilfunc \
+		-printf \
+		-shadow \
+		-rangeloops \
+		-unreachable \
+		-unsafeptr \
+		-unusedresult \
+		.
+else
+	GO_VET := @echo "go vet skipped -- not supported on this version of Go"
+endif
+
 default: fmt vet lint build quicktest
 
 install:
@@ -34,25 +65,8 @@ fmt:
 		exit 1; \
 	fi
 
-# Only run on go1.5+
 vet:
-	@go tool -n vet >/dev/null 2>&1; \
-		if [ $$? -eq 0 ]; then \
-			echo "go vet" ; \
-			go tool vet \
-				-atomic \
-				-bool \
-				-copylocks \
-				-nilfunc \
-				-printf \
-				-shadow \
-				-rangeloops \
-				-unreachable \
-				-unsafeptr \
-				-unusedresult \
-				. ; \
-		fi ;
-
+	$(GO_VET)
 
 # https://github.com/golang/lint
 # go get github.com/golang/lint/golint

search_test.go

@@ -24,7 +24,7 @@ func TestNewEntry(t *testing.T) {
 		}
 		testEntry := NewEntry(dn, attributes)
 		if !reflect.DeepEqual(executedEntry, testEntry) {
-			t.Fatalf("subsequent calls to NewEntry did not yield the same result:\n\texpected:\n\t%s\n\tgot:\n\t%s\n", executedEntry, testEntry)
+			t.Fatalf("subsequent calls to NewEntry did not yield the same result:\n\texpected:\n\t%v\n\tgot:\n\t%v\n", executedEntry, testEntry)
 		}
 		iteration = iteration + 1
 	}