lib, lang, docs: Add --only-unify option

This adds a new run flag for the lang frontend to exit immediately following type unification. This makes it easier to use this as a step in CI, and also to type the execution for performance comparison reasons.
RincewindsHat · Jan 2, 2024 · 24054f9 · 24054f9
1 parent 32ca815
commit 24054f9
Show file tree

Hide file tree

Showing 3 changed files with 36 additions and 2 deletions.
diff --git a/docs/faq.md b/docs/faq.md
@@ -216,6 +216,21 @@ requires a number of seconds as an argument.
 ./mgmt run lang examples/lang/hello0.mcl --converged-timeout=5
 ```
 
+### Can I run `mgmt` for type-checking only?
+
+Yes, you can, add the `--only-unify` option to the lang frontend while using the
+`run` command, and it will exit after type unification.
+
+#### Example:
+
+```
+./mgmt run --tmp-prefix lang --only-unify examples/lang/hello0.mcl
+```
+
+It will also print how long it took on either success or failure. Keep in mind
+that even if you pass type unification, an `mgmt` run can still fail later on
+for other reasons, although these are mostly runtime considerations.
+
 ### Why does my file resource error with `no such file or directory`?
 
 If you create a file resource and only specify the content like this:

diff --git a/lang/gapi/gapi.go b/lang/gapi/gapi.go
@@ -24,6 +24,7 @@ import (
  "fmt"
  "strings"
  "sync"
+ "time"
 
  "github.com/purpleidea/mgmt/gapi"
  "github.com/purpleidea/mgmt/lang"
@@ -97,6 +98,10 @@ func (obj *GAPI) CliFlags(command string) []cli.Flag {
  Name: "update",
  Usage: "update all dependencies to the latest versions",
  },
+ &cli.BoolFlag{
+ Name: "only-unify",
+ Usage: "stop after type unification",
+ },
  }
  result = append(result, runFlags...)
  }
@@ -318,14 +323,25 @@ func (obj *GAPI) Cli(cliInfo *gapi.CliInfo) (*gapi.Deploy, error) {
  }
  }
  logf("running type unification...")
+ startTime := time.Now()
  unifier := &unification.Unifier{
  AST: iast,
  Solver: unification.SimpleInvariantSolverLogger(unificationLogf),
  Debug: debug,
  Logf: unificationLogf,
  }
- if err := unifier.Unify(); err != nil {
- return nil, errwrap.Wrapf(err, "could not unify types")
+ unifyErr := unifier.Unify()
+ delta := time.Since(startTime)
+ if unifyErr != nil {
+ if c.Bool("only-unify") {
+ logf("type unification failed after %s", delta)
+ }
+ return nil, errwrap.Wrapf(unifyErr, "could not unify types")
+ }
+
+ if c.Bool("only-unify") {
+ logf("type unification succeeded in %s", delta)
+ return nil, nil // we end early
  }
 
  // get the list of needed files (this is available after SetScope)

diff --git a/lib/run.go b/lib/run.go
@@ -79,6 +79,9 @@ func run(c *cli.Context, name string, gapiObj gapi.GAPI) error {
  if err != nil {
  return errwrap.Wrapf(err, "cli parse error")
  }
+ if c.Bool("only-unify") && deploy == nil {
+ return nil // we end early
+ }
  obj.Deploy = deploy
  if obj.Deploy == nil {
  // nobody activated, but we'll still watch the etcd deploy chan,