Warn user about provider version 0.0.0 (#2281)

Signed-off-by: Ilia Gogotchuri <ilia.gogotchuri0@gmail.com>

CHANGELOG.md

@@ -46,6 +46,7 @@ ENHANCEMENTS:
 * Changes to encryption configuration now auto-apply the migration ([#2232](https://github.com/opentofu/opentofu/pull/2232))
 * References to vars, data, etc. are now usable in variable validation ([#2216](https://github.com/opentofu/opentofu/pull/2216))
 * `AzureRM` backend now support `timeout_seconds` with default timeout of 300 seconds ([#2263](https://github.com/opentofu/opentofu/pull/2263))
+* Adds warning about provider version `0.0.0` ([#2281](https://github.com/opentofu/opentofu/pull/2281))
 
 BUG FIXES:
 * `templatefile` no longer crashes if the given filename is derived from a sensitive value. ([#1801](https://github.com/opentofu/opentofu/issues/1801))

internal/getproviders/filesystem_mirror_source.go

@@ -7,7 +7,9 @@ package getproviders
 
 import (
 	"context"
+	"fmt"
 
+	"github.com/apparentlymart/go-versions/versions"
 	"github.com/opentofu/opentofu/internal/addrs"
 )
 
@@ -54,7 +56,16 @@ func (s *FilesystemMirrorSource) AvailableVersions(ctx context.Context, provider
 		ret = append(ret, v)
 	}
 	ret.Sort()
-	return ret, nil, nil
+	// Check the existence of provider version 0.0.0 in the filesystem and warn the user about it
+	// If it exists, it will be the first element in the sorted list
+	var warnings Warnings
+	if len(ret) > 0 && ret[0] == versions.Unspecified {
+		warning := fmt.Sprintf("Provider %s has an unspecified (0.0.0) version available in the filesystem mirror, source at %s. It will not be used. \n"+
+			"If the version 0.0.0 is intended to represent a non-published provider, consider using dev_overrides - https://opentofu.org/docs/cli/config/config-file/#development-overrides-for-provider-developers",
+			provider, s.baseDir)
+		warnings = append(warnings, warning)
+	}
+	return ret, warnings, nil
 }
 
 // PackageMeta checks to see if the source's base directory contains a

internal/getproviders/filesystem_mirror_source_test.go

@@ -7,6 +7,7 @@ package getproviders
 
 import (
 	"context"
+	"strings"
 	"testing"
 
 	"github.com/apparentlymart/go-versions/versions"
@@ -125,6 +126,30 @@ func TestFilesystemMirrorSourceAvailableVersions(t *testing.T) {
 	}
 }
 
+func TestFilesystemMirrorSourceAvailableVersions_Unspecified(t *testing.T) {
+	unspecifiedProvider := addrs.Provider{
+		Hostname:  svchost.Hostname("registry.opentofu.org"),
+		Namespace: "testnamespace",
+		Type:      "unspecified",
+	}
+	source := NewFilesystemMirrorSource("testdata/filesystem-mirror-unspecified")
+	got, warn, err := source.AvailableVersions(context.Background(), unspecifiedProvider)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Check that we got the unspecified version
+	if len(got) != 1 || got[0] != versions.Unspecified {
+		t.Fatalf("expected unspecified version, got %v", got)
+	}
+	// We should have unspecified (0.0.0) version warning
+	if len(warn) != 1 {
+		t.Fatalf("expected 1 warning, got %v", warn)
+	}
+	warningBit := "unspecified (0.0.0) version available in the filesystem mirror"
+	if !strings.Contains(warn[0], warningBit) {
+		t.Fatalf("expected warning to contain %q, got %q", warningBit, warn[0])
+	}
+}
 func TestFilesystemMirrorSourcePackageMeta(t *testing.T) {
 	t.Run("available platform", func(t *testing.T) {
 		source := NewFilesystemMirrorSource("testdata/filesystem-mirror")

internal/getproviders/testdata/filesystem-mirror-unspecified/registry.opentofu.org/testnamespace/unspecified/0.0.0/linux_amd64/unspecified-provider

@@ -0,0 +1 @@
+# This is just a placeholder file for discovery testing, not a real provider plugin.

internal/providercache/installer.go

@@ -291,10 +291,18 @@ NeedProvider:
 			// that context will fail immediately anyway.
 			return nil, err
 		}
-
 		if cb := evts.QueryPackagesBegin; cb != nil {
 			cb(provider, reqs[provider], locked[provider])
 		}
+		// Version 0.0.0 not supported
+		if err := checkUnspecifiedVersion(acceptableVersions); err != nil {
+			errs[provider] = err
+			if cb := evts.QueryPackagesFailure; cb != nil {
+				cb(provider, err)
+			}
+			continue
+		}
+
 		available, warnings, err := i.source.AvailableVersions(ctx, provider)
 		if err != nil {
 			errs[provider] = err
@@ -736,6 +744,15 @@ NeedProvider:
 	return locks, nil
 }
 
+// checkUnspecifiedVersion Check the presence of version 0.0.0 and return an error with a tip
+func checkUnspecifiedVersion(acceptableVersions versions.Set) error {
+	if !acceptableVersions.Exactly(versions.Unspecified) {
+		return nil
+	}
+	tip := "If the version 0.0.0 is intended to represent a non-published provider, consider using dev_overrides - https://opentofu.org/docs/cli/config/config-file/#development-overrides-for-provider-developers"
+	return fmt.Errorf("0.0.0 is not a valid provider version. \n%s", tip)
+}
+
 // InstallMode customizes the details of how an install operation treats
 // providers that have versions already cached in the target directory.
 type InstallMode rune

internal/providercache/installer_test.go

@@ -2315,6 +2315,12 @@ func TestEnsureProviderVersions_local_source(t *testing.T) {
 			wantHash: getproviders.NilHash, // installation fails for a provider with no executable
 			err:      "provider binary not found: could not find executable file starting with terraform-provider-executable",
 		},
+		"unspecified-version": {
+			provider: "null",
+			version:  "0.0.0",
+			wantHash: getproviders.NilHash,
+			err:      "0.0.0 is not a valid provider version. \nIf the version 0.0.0 is intended to represent a non-published provider, consider using dev_overrides - https://opentofu.org/docs/cli/config/config-file/#development-overrides-for-provider-developers",
+		},
 	}
 
 	for name, test := range tests {