From 754b7ebb65dac406ea894da20674d28d9df00c08 Mon Sep 17 00:00:00 2001
From: Martin Atkins <mart@degeneration.co.uk>
Date: Fri, 13 Mar 2020 11:22:24 -0700
Subject: [PATCH] command: Expose providercache package objects for use
 elsewhere

These new functions allow command implementations to get hold of the
providercache objects and installation source object derived from the
current CLI configuration.
---
 command/meta_providers.go           | 63 +++++++++++++++++++++++++++++
 internal/getproviders/types.go      |  6 +++
 internal/providercache/installer.go |  2 +-
 3 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 command/meta_providers.go

diff --git a/command/meta_providers.go b/command/meta_providers.go
new file mode 100644
index 000000000..8c2a554cf
--- /dev/null
+++ b/command/meta_providers.go
@@ -0,0 +1,63 @@
+package command
+
+import (
+	"path/filepath"
+
+	"github.com/hashicorp/terraform/internal/getproviders"
+	"github.com/hashicorp/terraform/internal/providercache"
+)
+
+// providerLocalCacheDir returns an object representing the
+// configuration-specific local cache directory. This is the
+// only location consulted for provider plugin packages for Terraform
+// operations other than provider installation.
+//
+// Only the provider installer (in "terraform init") is permitted to make
+// modifications to this cache directory. All other commands must treat it
+// as read-only.
+func (m *Meta) providerLocalCacheDir() *providercache.Dir {
+	dir := filepath.Join(m.DataDir(), "plugins")
+	if dir == "" {
+		return nil // cache disabled
+	}
+	return providercache.NewDir(dir)
+}
+
+// providerGlobalCacheDir returns an object representing the shared global
+// provider cache directory, used as a read-through cache when installing
+// new provider plugin packages.
+//
+// This function may return nil, in which case there is no global cache
+// configured and new packages should be downloaded directly into individual
+// configuration-specific cache directories.
+func (m *Meta) providerGlobalCacheDir() *providercache.Dir {
+	dir := m.PluginCacheDir
+	if dir == "" {
+		return nil // cache disabled
+	}
+	return providercache.NewDir(dir)
+}
+
+// providerInstallSource returns an object that knows how to consult one or
+// more external sources to determine the availability of and package
+// locations for versions of Terraform providers that are available for
+// automatic installation.
+//
+// This returns the standard provider install source that consults a number
+// of directories selected either automatically or via the CLI configuration.
+// Users may choose to override this during a "terraform init" command by
+// specifying one or more -plugin-dir options, in which case the installation
+// process will construct its own source consulting only those directories
+// and use that instead.
+func (m *Meta) providerInstallSource() getproviders.Source {
+	// A provider source should always be provided in normal use, but our
+	// unit tests might not always populate Meta fully and so we'll be robust
+	// by returning a non-nil source that just always answers that no plugins
+	// are available.
+	if m.ProviderSource == nil {
+		// A multi-source with no underlying sources is effectively an
+		// always-empty source.
+		return getproviders.MultiSource(nil)
+	}
+	return m.ProviderSource
+}
diff --git a/internal/getproviders/types.go b/internal/getproviders/types.go
index 9d720be66..fce626d1d 100644
--- a/internal/getproviders/types.go
+++ b/internal/getproviders/types.go
@@ -35,6 +35,12 @@ func ParseVersion(str string) (Version, error) {
 	return versions.ParseVersion(str)
 }
 
+// ParseVersionConstraints parses a "Ruby-like" version constraint string
+// into a VersionConstraints value.
+func ParseVersionConstraints(str string) (VersionConstraints, error) {
+	return constraints.ParseRubyStyleMulti(str)
+}
+
 // Platform represents a target platform that a provider is or might be
 // available for.
 type Platform struct {
diff --git a/internal/providercache/installer.go b/internal/providercache/installer.go
index 72ef59106..60ae2bac7 100644
--- a/internal/providercache/installer.go
+++ b/internal/providercache/installer.go
@@ -345,7 +345,7 @@ func (err InstallerError) Error() string {
 	b.WriteString("some providers could not be installed:\n")
 	for _, addr := range addrs {
 		providerErr := err.ProviderErrors[addr]
-		fmt.Fprintf(&b, "- %s: %s\n", addr, providerErr.Error())
+		fmt.Fprintf(&b, "- %s: %s\n", addr, providerErr)
 	}
 	return b.String()
 }