Makefile: fix lint rules

use errors.Join

.build.yml

@@ -1,19 +0,0 @@
-image: alpine/edge
-packages:
-  - go
-  - git
-  - make
-sources:
-  - https://git.sr.ht/~motiejus/undocker
-tasks:
-  - setup: |
-      go install honnef.co/go/tools/cmd/staticcheck@latest
-  - test: |
-      make -C undocker coverage.html
-  - lint: |
-      make -C undocker -O -j$(nproc) lint
-  - binaries: |
-      make -C undocker -O -j$(nproc) sha256sum.txt
-      cat undocker/sha256sum.txt
-artifacts:
-  - undocker/coverage.html

.gitignore

@@ -1,3 +1,4 @@
+/undocker
 /undocker-*
 coverage.html
 sha256sum.txt*

LICENSE

@@ -1,19 +1,202 @@
-Copyright (c) 2021 Motiejus Jakštys
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
+                                 Apache License
-of this software and associated documentation files (the "Software"), to deal
+                           Version 2.0, January 2004
-in the Software without restriction, including without limitation the rights
+                        http://www.apache.org/licenses/
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in all
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-copies or substantial portions of the Software.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   1. Definitions.
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+      "License" shall mean the terms and conditions for use, reproduction,
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+      and distribution as defined by Sections 1 through 9 of this document.
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+      "Licensor" shall mean the copyright owner or entity authorized by
-SOFTWARE.
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 2021 Motiejus Jakštys
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

Makefile

@@ -1,58 +1,29 @@
+SCRIPTS = $(shell awk '/#!\/usr\/bin\/env (ba)?sh/&&FNR==1{print FILENAME}' $(shell git ls-files))
 GODEPS = $(shell git ls-files '*.go' go.mod go.sum)
-GOBIN = $(shell go env GOPATH)/bin/
-
-GOOSARCHS = $(sort \
-			darwin/amd64 \
-			darwin/arm64 \
-			linux/amd64 \
-			linux/arm64 \
-			windows/amd64/.exe \
-			windows/arm64/.exe)
 
 VSN ?= $(shell git describe --dirty)
 VSNHASH = $(shell git rev-parse --verify HEAD)
 LDFLAGS = -ldflags "-X main.Version=$(VSN) -X main.VersionHash=$(VSNHASH)"
 
+undocker: ## builds binary for the current architecture
+	go build $(LDFLAGS) -o $@
+
 .PHONY: test
-test:
+test: coverage.out
-	go test -race -cover ./...
-
-define undockertarget
-UNDOCKERS += undocker-$(1)-$(2)-$(VSN)$(firstword $(3))
-undocker-$(1)-$(2)-$(VSN)$(firstword $(3)): $(GODEPS)
-	CGO_ENABLED=0 GOOS=$(1) GOARCH=$(2) go build $(LDFLAGS) -o $$@
-endef
-
-$(foreach goosarch,$(GOOSARCHS),\
-	$(eval $(call undockertarget,$(word 1,$(subst /, ,$(goosarch))),$(word 2,$(subst /, ,$(goosarch))),$(word 3,$(subst /, ,$(goosarch))))))
-
-.PHONY: all
-all: $(UNDOCKERS)
 
 .PHONY: lint
-lint: vet staticcheck
+lint:
-
-.PHONY: vet
-vet:
 	go vet ./...
-
+	staticcheck -f stylish ./...
-.PHONY: staticcheck
+	shellcheck $(SCRIPTS)
-staticcheck:
-	$(GOBIN)staticcheck -f stylish ./...
 
 .INTERMEDIATE: coverage.out
 coverage.out: $(GODEPS)
-	go test -coverprofile $@ ./...
+	go test -race -cover -coverprofile $@ ./...
 
 coverage.html: coverage.out
 	go tool cover -html=$< -o $@
 
-sha256sum.txt: $(UNDOCKERS)
-	sha256sum $(UNDOCKERS) > $@
-
-sha256sum.txt.asc: sha256sum.txt
-	gpg --clearsign $<
-
 .PHONY: clean
 clean:
-	rm -f undocker-*-v* coverage.html sha256sum.txt sha256sum.txt.asc
+	rm -f undocker coverage.html

README.md

@@ -1,11 +1,19 @@
-[![godocs.io](http://godocs.io/git.sr.ht/~motiejus/undocker?status.svg)](http://godocs.io/git.sr.ht/~motiejus/undocker)
+[![godocs.io](http://godocs.io/git.jakstys.lt/motiejus/undocker?status.svg)](http://godocs.io/git.jakstys.lt/motiejus/undocker)
-[![builds.sr.ht status](https://builds.sr.ht/~motiejus/undocker.svg)](https://builds.sr.ht/~motiejus/undocker?)
 
 Undocker
 --------
 
 Converts a Docker image (a bunch of layers) to a flattened "rootfs" tarball.
 
+Project Status
+--------------
+
+The project was announced to be deprecated in the beginning of 2024, but the
+maintainer has an interest in Docker ecosystem again, thus will maintain it
+somewhat starting at mid-2024.
+
+The author has some significant changes in mind, but the timeline is unknown.
+
 Why?
 ----
 
@@ -18,7 +26,19 @@ and application isolation ("container") runtimes: once the docker image is
 extracted, it can be run with old-fashioned tools: lxc, systemd-nspawn,
 systemd, FreeBSD Jails, and many others.
 
-Undocker has no dependencies outside Golang stdlib.
+
+Installation
+------------
+
+Build it like this for the "current" platform:
+
+```
+$ make undocker
+```
+
+`make -B` will print the extra flags (`-X <...>`) for cross-compiling with
+other archs. It's all `go build <...>` in the back, and depends only on Go's
+compiler and stdlib.
 
 Usage: convert docker image to rootfs
 -------------------------------------
@@ -27,69 +47,53 @@ Download `busybox` docker image from docker hub and convert it to a rootfs:
 
 ```
 $ skopeo copy docker://docker.io/busybox:latest docker-archive:busybox.tar
-$ undocker busybox.tar - | tar -tv | head -10
+$ undocker busybox.tar - | tar -xv | sponge | head -10; echo '<...>'
-drwxr-xr-x 0/0               0 2021-05-17 22:07 bin/
+bin/
--rwxr-xr-x 0/0         1149184 2021-05-17 22:07 bin/[
+bin/[
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/[[ link to bin/[
+bin/[[
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/acpid link to bin/[
+bin/acpid
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/add-shell link to bin/[
+bin/add-shell
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/addgroup link to bin/[
+bin/addgroup
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/adduser link to bin/[
+bin/adduser
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/adjtimex link to bin/[
+bin/adjtimex
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/ar link to bin/[
+bin/ar
-hrwxr-xr-x 0/0               0 2021-05-17 22:07 bin/arch link to bin/[
+bin/arch
+<...>
 ```
 
-You can also refer [here][2] for other ways to download Docker images. There
+Refer [here][2] for other ways to download Docker images. There are many.
-are many.
 
-Converting a [1.1GB Docker image with 77
+On author's laptop converting a [1.1GB Docker image with 77
-layers](https://hub.docker.com/r/homeassistant/home-assistant) takes around 4
+layers](https://hub.docker.com/r/homeassistant/home-assistant) takes around 3
-seconds and on a reasonably powerful Intel laptop.
+seconds and uses ~65MB of residential memory.
 
-Usage example: systemd-nspawn
+Usage example: systemd
------------------------------
+----------------------
-
-Start with systemd-nspawn:
-
-```
-systemd-nspawn -D $PWD busybox httpd -vfp 8080
-```
-
-Usage example: plain old systemd
---------------------------------
 
 ```
 systemd-run \
   --wait --pty --collect --service-type=exec \
+  -p RootDirectory=$PWD \
+  -p ProtectProc=invisible \
   -p PrivateUsers=true \
   -p DynamicUser=yes \
-  -p ProtectProc=invisible \
-  -p RootDirectory=$PWD \
   -- busybox httpd -vfp 8080
 ```
 
-Good things like `PrivateUsers`, `DynamicUser`, `ProtectProc` and other
+[Systemd protections][1] like `PrivateUsers`, `DynamicUser`, `ProtectProc` and
-[systemd protections][1] are available, just like to any systemd unit.
+others are available, just like to any systemd unit.
 
 Similar Projects
 ----------------
 
 * [rootfs_builder](https://github.com/ForAllSecure/rootfs_builder)
 
-Changelog
----------
-
-**v1.0**
-
-* initial release: `rootfs.Flatten` and a simple command-line application.
-
 Contributions
 -------------
 
 The following contributions may be accepted:
 
-- Pull requests (patchsets) with accompanying tests.
+- Patchsets, with accompanying tests.
 - Regression reports.
 
 If you found a container that undocker cannot extract, or extracts incorrectly
@@ -100,6 +104,11 @@ Reports of regression reports must provide examples of "works before" and "does
 not work after". Issues without an accompanying patch will most likely be
 rejected.
 
+Communication
+-------------
+
+Feel free to ping me [directly][motiejus-comms].
+
 LICENSE
 -------
 
@@ -107,3 +116,5 @@ MIT
 
 [1]: https://www.freedesktop.org/software/systemd/man/systemd.exec.html
 [2]: https://fly.io/blog/docker-without-docker/
+
+[motiejus-comms]: https://jakstys.lt/contact/

go.mod

@@ -1,3 +1,3 @@
-module git.sr.ht/~motiejus/undocker
+module git.jakstys.lt/motiejus/undocker
 
-go 1.16
+go 1.20

main.go

@@ -2,13 +2,14 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"runtime"
 
-	"git.sr.ht/~motiejus/undocker/rootfs"
+	"git.jakstys.lt/motiejus/undocker/rootfs"
 )
 
 var Version = "unknown"
@@ -42,7 +43,7 @@ func main() {
 
 	c := &command{flattener: rootfs.Flatten, Stdout: os.Stdout}
 	if err := c.execute(os.Args[1], os.Args[2]); err != nil {
-		fmt.Printf("Error: %v\n", err)
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
 		os.Exit(1)
 	}
 	os.Exit(0)
@@ -53,16 +54,13 @@ type command struct {
 	Stdout    io.Writer
 }
 
-func (c *command) execute(infile string, outfile string) (err error) {
+func (c *command) execute(infile string, outfile string) (_err error) {
 	rd, err := os.Open(infile)
 	if err != nil {
 		return err
 	}
 	defer func() {
-		err1 := rd.Close()
+		_err = errors.Join(_err, rd.Close())
-		if err == nil {
-			err = err1
-		}
 	}()
 
 	var out io.Writer
@@ -74,9 +72,10 @@ func (c *command) execute(infile string, outfile string) (err error) {
 			return fmt.Errorf("create: %w", err)
 		}
 		defer func() {
-			err1 := outf.Close()
+			if _err != nil {
-			if err == nil {
+				_err = errors.Join(_err, os.Remove(outfile))
-				err = err1
+			} else {
+				_err = errors.Join(_err, outf.Close())
 			}
 		}()
 		out = outf

main_test.go

@@ -2,8 +2,9 @@ package main
 
 import (
 	"bytes"
+	"errors"
 	"io"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"regexp"
 	"testing"
@@ -13,18 +14,20 @@ func TestExecute(t *testing.T) {
 	var _foo = []byte("foo foo")
 
 	tests := []struct {
-		name    string
+		name      string
-		fixture func(*testing.T, string)
+		fixture   func(*testing.T, string)
-		infile  string
+		flattener func(io.ReadSeeker, io.Writer) error
-		outfile string
+		infile    string
-		wantErr string
+		outfile   string
+		wantErr   string
+		assertion func(*testing.T, string)
 	}{
 		{
 			name:   "ok passthrough via stdout",
 			infile: "t10-in.txt",
 			fixture: func(t *testing.T, dir string) {
 				fname := filepath.Join(dir, "t10-in.txt")
-				if err := ioutil.WriteFile(fname, _foo, 0644); err != nil {
+				if err := os.WriteFile(fname, _foo, 0644); err != nil {
 					t.Fatalf("unexpected error: %v", err)
 				}
 			},
@@ -35,12 +38,37 @@ func TestExecute(t *testing.T) {
 			infile: "t20-in.txt",
 			fixture: func(t *testing.T, dir string) {
 				fname := filepath.Join(dir, "t20-in.txt")
-				if err := ioutil.WriteFile(fname, _foo, 0644); err != nil {
+				if err := os.WriteFile(fname, _foo, 0644); err != nil {
 					t.Fatalf("unexpected error: %v", err)
 				}
 			},
 			outfile: "t20-out.txt",
 		},
+		{
+			name:   "bad flattener should remove the file",
+			infile: "t30-in.txt",
+			fixture: func(t *testing.T, dir string) {
+				fname := filepath.Join(dir, "t30-in.txt")
+				if err := os.WriteFile(fname, _foo, 0644); err != nil {
+					t.Fatalf("unexpected error: %v", err)
+				}
+			},
+			flattener: flattenBad,
+			outfile:   "t30-out.txt",
+			wantErr:   "some error",
+			assertion: func(t *testing.T, dir string) {
+				d, err := os.ReadDir(dir)
+				if err != nil {
+					t.Fatalf("unexpected error: %v", err)
+				}
+				if len(d) != 1 {
+					t.Fatalf("expected 1 entry, got %d", len(d))
+				}
+				if d[0].Name() != "t30-in.txt" {
+					t.Fatalf("expected to find only t30-in.txt, got %s", d[0].Name())
+				}
+			},
+		},
 		{
 			name:    "infile does not exist",
 			infile:  "t3-does-not-exist.txt",
@@ -57,7 +85,10 @@ func TestExecute(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			dir := t.TempDir()
 			var stdout bytes.Buffer
-			c := &command{Stdout: &stdout}
+			if tt.flattener == nil {
+				tt.flattener = flattenPassthrough
+			}
+
 			if tt.fixture != nil {
 				tt.fixture(t, dir)
 			}
@@ -65,9 +96,14 @@ func TestExecute(t *testing.T) {
 				tt.outfile = filepath.Join(dir, tt.outfile)
 			}
 			inf := filepath.Join(dir, tt.infile)
-			c.flattener = flattenPassthrough
 
+			c := &command{Stdout: &stdout, flattener: tt.flattener}
 			err := c.execute(inf, tt.outfile)
+
+			if tt.assertion != nil {
+				tt.assertion(t, dir)
+			}
+
 			if tt.wantErr != "" {
 				if err == nil {
 					t.Fatal("expected error, got nil")
@@ -78,21 +114,22 @@ func TestExecute(t *testing.T) {
 				}
 				return
 			}
-			var out []byte
 			if err != nil {
 				t.Fatalf("unexpected error: %v", err)
 			}
+			var out []byte
 			if tt.outfile == "-" {
 				out = stdout.Bytes()
 			} else {
-				out, err = ioutil.ReadFile(tt.outfile)
+				out, err = os.ReadFile(tt.outfile)
 				if err != nil {
 					t.Fatalf("unexpected error: %v", err)
 				}
 			}
 			if !bytes.Equal([]byte("foo foo"), out) {
-				t.Errorf("out != foo foo: %s", string(out))
+				t.Errorf("out != foo foo: %q", string(out))
 			}
+
 		})
 	}
 }
@@ -101,3 +138,7 @@ func flattenPassthrough(r io.ReadSeeker, w io.Writer) error {
 	_, err := io.Copy(w, r)
 	return err
 }
+
+func flattenBad(_ io.ReadSeeker, _ io.Writer) error {
+	return errors.New("some error")
+}

release

@@ -1,32 +1,25 @@
-#!/bin/bash
+#!/usr/bin/env bash
 set -euo pipefail
 
-err() {
+_err(){ >&2 echo "ERROR: $*"; exit 1; }
-    >&2 echo "ERROR: $*"
-    exit 1
-}
 
-[[ -n "$(git status --porcelain)" ]] && \
+git status --porcelain | grep -q "" &&
-    err "working tree is dirty, commit your changes first."
+    _err "working tree is dirty, commit your changes first."
 
-[[ ! "$1" =~ ^v([0-9]+)\.([0-9]+)(\.([0-9]+))?$ ]] && \
+[[ "$1" =~ ^v([0-9]+)\.([0-9]+)(\.([0-9]+))?(-rc([0-9]+))?$ ]] || \
-    err "arg1 accepts the following formats: v1.0 v1.0.0"
+    _err "arg1 accepts the following formats: v1.0 v1.0.0 v1.0-rc1 v1.0.1-rc1"
 
-[[ -n "$(git tag | grep "^$1$")" ]] && \
+git tag | grep -q "^$1$" &&
-    err "tag $1 already exists"
+    _err "tag $1 already exists"
+
+# sanity test: do the tests pass?
+make -B -j"$(nproc)" test lint
 
 last_tag=$(git tag | tail -1)
 
-make -B -j$(nproc) VSN=$1 sha256sum.txt.asc
-
 {
-    echo undocker $1
+    echo undocker "$1"
     echo
-    echo Changelog since $last_tag:
+    echo Changelog since "$last_tag":
-    git log --pretty=format:"- [%cn] %s" $last_tag..HEAD
+    git log --pretty=format:"- [%an] %s" "$last_tag"..HEAD
-    echo
+} | git tag -F - "$1"
-    echo
-    echo sha256sums of released binaries:
-    cat sha256sum.txt
-    echo
-} | git tag -u motiejus@jakstys.lt -F - "$1"

rootfs/rootfs.go

@@ -69,7 +69,7 @@ func Flatten(rd io.ReadSeeker, w io.Writer) (_err error) {
 			if err != nil {
 				return err
 			}
-			layerOffsets[hdr.Name] = here
+			layerOffsets[strings.TrimPrefix(hdr.Name, "./")] = here
 		}
 	}
 
@@ -82,7 +82,7 @@ func Flatten(rd io.ReadSeeker, w io.Writer) (_err error) {
 	for i, name := range manifest[0].Layers {
 		layers[i] = nameOffset{
 			name:   name,
-			offset: layerOffsets[name],
+			offset: layerOffsets[strings.TrimPrefix(name, "./")],
 		}
 	}
 
@@ -144,12 +144,7 @@ func Flatten(rd io.ReadSeeker, w io.Writer) (_err error) {
 
 	tw := tar.NewWriter(w)
 	defer func() {
-		// Avoiding use of multierr: if error is present, return
+		_err = errors.Join(_err, tw.Close())
-		// that. Otherwise return whatever `Close` returns.
-		err1 := tw.Close()
-		if _err == nil {
-			_err = err1
-		}
 	}()
 	// iterate through all layers, all files, and write files.
 	for i, no := range layers {

rootfs/rootfs_test.go

@@ -7,7 +7,7 @@ import (
 	"reflect"
 	"testing"
 
-	"git.sr.ht/~motiejus/undocker/rootfs/internal/tartest"
+	"git.jakstys.lt/motiejus/undocker/rootfs/internal/tartest"
 )
 
 type (