Remove exit error types (#352)

* remove exit error types * reinstate error wrapping for context errs
hashicorp · Feb 20, 2023 · a7e018d · a7e018d
1 parent 0fb01be
commit a7e018d
Show file tree

Hide file tree

Showing 9 changed files with 79 additions and 451 deletions.
diff --git a/tfexec/cmd_default.go b/tfexec/cmd_default.go
@@ -40,11 +40,14 @@ func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	}
 
 	err = cmd.Start()
-	if err == nil && ctx.Err() != nil {
-		err = ctx.Err()
+	if ctx.Err() != nil {
+		return cmdErr{
+			err:    err,
+			ctxErr: ctx.Err(),
+		}
 	}
 	if err != nil {
-		return tf.wrapExitError(ctx, err, "")
+		return err
 	}
 
 	var errStdout, errStderr error
@@ -66,19 +69,22 @@ func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	wg.Wait()
 
 	err = cmd.Wait()
-	if err == nil && ctx.Err() != nil {
-		err = ctx.Err()
+	if ctx.Err() != nil {
+		return cmdErr{
+			err:    err,
+			ctxErr: ctx.Err(),
+		}
 	}
 	if err != nil {
-		return tf.wrapExitError(ctx, err, errBuf.String())
+		return err
 	}
 
 	// Return error if there was an issue reading the std out/err
 	if errStdout != nil && ctx.Err() != nil {
-		return tf.wrapExitError(ctx, errStdout, errBuf.String())
+		return errStdout
 	}
 	if errStderr != nil && ctx.Err() != nil {
-		return tf.wrapExitError(ctx, errStderr, errBuf.String())
+		return errStderr
 	}
 
 	return nil

diff --git a/tfexec/cmd_linux.go b/tfexec/cmd_linux.go
@@ -45,11 +45,14 @@ func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	}
 
 	err = cmd.Start()
-	if err == nil && ctx.Err() != nil {
-		err = ctx.Err()
+	if ctx.Err() != nil {
+		return cmdErr{
+			err:    err,
+			ctxErr: ctx.Err(),
+		}
 	}
 	if err != nil {
-		return tf.wrapExitError(ctx, err, "")
+		return err
 	}
 
 	var errStdout, errStderr error
@@ -71,19 +74,22 @@ func (tf *Terraform) runTerraformCmd(ctx context.Context, cmd *exec.Cmd) error {
 	wg.Wait()
 
 	err = cmd.Wait()
-	if err == nil && ctx.Err() != nil {
-		err = ctx.Err()
+	if ctx.Err() != nil {
+		return cmdErr{
+			err:    err,
+			ctxErr: ctx.Err(),
+		}
 	}
 	if err != nil {
-		return tf.wrapExitError(ctx, err, errBuf.String())
+		return err
 	}
 
 	// Return error if there was an issue reading the std out/err
 	if errStdout != nil && ctx.Err() != nil {
-		return tf.wrapExitError(ctx, errStdout, errBuf.String())
+		return errStdout
 	}
 	if errStderr != nil && ctx.Err() != nil {
-		return tf.wrapExitError(ctx, errStderr, errBuf.String())
+		return errStderr
 	}
 
 	return nil

diff --git a/tfexec/errors.go b/tfexec/errors.go
@@ -1,6 +1,9 @@
 package tfexec
 
-import "fmt"
+import (
+	"context"
+	"fmt"
+)
 
 // this file contains non-parsed exported errors
 
@@ -37,3 +40,25 @@ type ErrManualEnvVar struct {
 func (err *ErrManualEnvVar) Error() string {
 	return fmt.Sprintf("manual setting of env var %q detected", err.Name)
 }
+
+// cmdErr is a custom error type to be returned when a cmd exits with a context
+// error such as context.Canceled or context.DeadlineExceeded.
+// The type is specifically designed to respond true to errors.Is for these two
+// errors.
+// See https://github.com/golang/go/issues/21880 for why this is necessary.
+type cmdErr struct {
+	err    error
+	ctxErr error
+}
+
+func (e cmdErr) Is(target error) bool {
+	switch target {
+	case context.DeadlineExceeded, context.Canceled:
+		return e.ctxErr == context.DeadlineExceeded || e.ctxErr == context.Canceled
+	}
+	return false
+}
+
+func (e cmdErr) Error() string {
+	return e.err.Error()
+}