cmd/cue: add a forwards compatibility test case for bugfix releases

When loading a CUE module which uses a higher language.version than
the current language version supported by cmd/cue, it does not matter
whether the version is higher due to a higher bugfix number
or a higher minor or even major number.

We treat the language.version version as a hard version minimum,
even though the language spec should not change in bugfix releases,
for the sake of consistent and intuitive behavior.
language.version also affects the module.cue file schema to use,
and that can indeed change in bugfix releases from time to time.

We already had a test case for a CUE module with a higher minor number
in its language.version; add one with a higher bugfix number as well.

While here, move "cd" testscript commands to be next to the top-level
comment which describes each test case set up via txtar.

For #3197.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: Ied3603b95662656fa45063421f730e7788646b8e
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1196300
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Paul Jolly <[email protected]>
Reviewed-by: Roger Peppe <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

Author: mvdan

cmd/cue/cmd/script_test.go

@@ -47,6 +47,7 @@ import (
 	"cuelang.org/go/cue/parser"
 	"cuelang.org/go/internal/cuetest"
 	"cuelang.org/go/internal/cueversion"
+	"cuelang.org/go/internal/mod/semver"
 	"cuelang.org/go/internal/registrytest"
 )
 
@@ -257,7 +258,11 @@ func TestScript(t *testing.T) {
 			e.Vars = append(e.Vars,
 				"GOPROXY="+srv.URL,
 				"GONOSUMDB=*", // GOPROXY is a private proxy
+
+				// The current language version which would be added by `cue mod init`, e.g. v0.10.0.
 				"CUE_LANGUAGE_VERSION="+cueversion.LanguageVersion(),
+				// A later language version which only increases the bugfix release, e.g. v0.10.99.
+				"CUE_LANGUAGE_VERSION_BUGFIX="+semver.MajorMinor(cueversion.LanguageVersion())+".99",
 			)
 			entries, err := os.ReadDir(e.WorkDir)
 			if err != nil {

cmd/cue/cmd/testdata/script/module_compatibility_backwards.txtar

@@ -17,10 +17,10 @@ env CUE_REGISTRY=$MEMREGISTRY+insecure
 
 # A module that was created before the modules experiment,
 # without a major version suffix nor a language version.
+cd ${WORK}/premodules
 
 # Downstream consumption via cue.mod/*/ works.
 # Downstream consumption via a registry is not possible as its module path lacks a major version suffix.
-cd ${WORK}/premodules
 exec cue export
 stdout '"downstream": "hello from premodules.example"'
 
@@ -56,11 +56,11 @@ exec cue mod publish v0.0.2
 
 
 # A module that was created with a language.version of v0.8.0.
+cd ${WORK}/v0.8.0-downstream-deps
 
 # Downstream consumption via a registry works.
 # Note that we need to point CUE_REGISTRY back to the contents inside _registry/ below.
 env CUE_REGISTRY=${ORIG_CUE_REGISTRY}
-cd ${WORK}/v0.8.0-downstream-deps
 exec cue export
 stdout '"downstream": "hello from v0.8.0.example"'
 env CUE_REGISTRY=$MEMREGISTRY+insecure

cmd/cue/cmd/testdata/script/module_compatibility_forwards.txtar

@@ -9,11 +9,43 @@
 # cover scenarios where just one of them is too new,
 # as we should allow downstream consumption when only the module schema version is too new.
 
-# A module that was created with a language.version of v0.99.0 in the far future.
+# A module that was created with a language.version of ${CUE_LANGUAGE_VERSION_BUGFIX},
+# which is like the current ${CUE_LANGUAGE_VERSION} but with a higher bugfix release.
+# For example, if ${CUE_LANGUAGE_VERSION} is v0.10.0 or v0.10.5, ${CUE_LANGUAGE_VERSION_BUGFIX} is v0.10.99.
+# Even though the language spec should not change in bugfix releases,
+# we still treat the language version as a hard minimum following semver.
+cd ${WORK}/bugfix-newer
+env-fill cue.mod/pkg/bugfix-newer.example/cue.mod/module.cue
 
 # TODO(mvdan): downstream consumption via cue.mod/*/ works when it should not,
 # because we do not yet use language.version as a minimum for parsing or evaluating CUE.
+exec cue export
+stdout '"downstream": "hello from bugfix-newer.example"'
+
+# TODO(mvdan): test downstream consumption via a registry; note that _registry/ complains
+# because it is unable to parse the module.cue file with a schema that is too new.
+
+# Continue inside the module's own directory as if we had cloned it directly.
+cd ${WORK}
+mv bugfix-newer/cue.mod/pkg/bugfix-newer.example bugfix-newer-downstream-direct
+cd bugfix-newer-downstream-direct
+
+# Downstream consumption via `cue export` does not work as we don't support the language spec version.
+! exec cue export
+cmp stderr ${WORK}/bugfix-newer-toonew.stderr
+
+# Upstream development and publishing is forbidden as we don't have or understand the schema.
+! exec cue mod tidy --check
+cmp stderr ${WORK}/bugfix-newer-toonew.stderr
+! exec cue mod publish v0.0.2
+cmp stderr ${WORK}/bugfix-newer-toonew.stderr
+
+
+# A module that was created with a language.version of v0.99.0 in the far future.
 cd ${WORK}/v0.99.0
+
+# TODO(mvdan): downstream consumption via cue.mod/*/ works when it should not,
+# because we do not yet use language.version as a minimum for parsing or evaluating CUE.
 exec cue export
 stdout '"downstream": "hello from v0.99.0.example"'
 
@@ -35,6 +67,26 @@ cmp stderr ${WORK}/v0.99.0-toonew.stderr
 ! exec cue mod publish v0.0.2
 cmp stderr ${WORK}/v0.99.0-toonew.stderr
 
+-- bugfix-newer-toonew.stderr --
+language version "v0.10.99" declared in module.cue is too new for current language version "v0.10.0"
+-- bugfix-newer/cue.mod/module.cue --
+module: "downstream.example"
+language: version: "v0.9.0"
+-- bugfix-newer/downstream.cue --
+package downstream
+import "bugfix-newer.example:root"
+downstream: root
+-- bugfix-newer/cue.mod/pkg/bugfix-newer.example/cue.mod/module.cue --
+module: "bugfix-newer.example"
+language: version: "${CUE_LANGUAGE_VERSION_BUGFIX}"
+-- bugfix-newer/cue.mod/pkg/bugfix-newer.example/root.cue --
+package root
+import "bugfix-newer.example/subpkg"
+subpkg
+-- bugfix-newer/cue.mod/pkg/bugfix-newer.example/subpkg/subpkg.cue --
+package subpkg
+"hello from bugfix-newer.example"
+
 -- v0.99.0-toonew.stderr --
 language version "v0.99.0" declared in module.cue is too new for current language version "v0.10.0"
 -- v0.99.0/cue.mod/module.cue --