Increase test coverage (#538)

Also fix array in map bug.

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,19 @@
-**Issue:** add link to pelletier/go-toml issue here
+<!--
+
+Thank you for your pull request!
+
+Please read the Code changes section of the CONTRIBUTING.md file,
+and make sure you have followed the instructions.
+
+https://github.com/pelletier/go-toml/blob/v2/CONTRIBUTING.md#code-changes
+
+-->
 
 Explanation of what this pull request does.
 
-More detailed description of the decisions being made and the reasons why (if the patch is non-trivial).
+More detailed description of the decisions being made and the reasons why (if
+the patch is non-trivial).
+
+---
+
+Paste `benchstat` results here

.github/workflows/coverage.yml

@@ -0,0 +1,23 @@
+name: coverage
+on:
+  push:
+    branches:
+      - v2
+  pull_request:
+    branches:
+      - v2
+
+jobs:
+  report:
+    runs-on: 'ubuntu-latest'
+    name: report
+    steps:
+      - uses: actions/checkout@master
+        with:
+          fetch-depth: 0
+      - name: Setup go
+        uses: actions/setup-go@master
+        with:
+          go-version: 1.16
+      - name: Run tests with coverage
+        run: ./ci.sh coverage -d "${GITHUB_BASE_REF-HEAD}"

.golangci.toml

@@ -24,7 +24,7 @@ enable = [
     # "exhaustivestruct",
     "exportloopref",
     "forbidigo",
-    "forcetypeassert",
+    # "forcetypeassert",
     "funlen",
     "gci",
     # "gochecknoglobals",
@@ -35,7 +35,7 @@ enable = [
     "gocyclo",
     "godot",
     "godox",
-    "goerr113",
+    # "goerr113",
     "gofmt",
     "gofumpt",
     "goheader",
@@ -57,7 +57,7 @@ enable = [
     "nakedret",
     "nestif",
     "nilerr",
-    "nlreturn",
+    # "nlreturn",
     "noctx",
     "nolintlint",
     "paralleltest",
@@ -80,5 +80,5 @@ enable = [
     "wastedassign",
     "whitespace",
     # "wrapcheck",
-    "wsl"
+    # "wsl"
 ]

CONTRIBUTING.md

@@ -1,74 +1,74 @@
-## Contributing
+# Contributing
 
 Thank you for your interest in go-toml! We appreciate you considering
 contributing to go-toml!
 
-The main goal is the project is to provide an easy-to-use TOML
-implementation for Go that gets the job done and gets out of your way –
-dealing with TOML is probably not the central piece of your project.
+The main goal is the project is to provide an easy-to-use and efficient TOML
+implementation for Go that gets the job done and gets out of your way – dealing
+with TOML is probably not the central piece of your project.
 
-As the single maintainer of go-toml, time is scarce. All help, big or
-small, is more than welcomed!
+As the single maintainer of go-toml, time is scarce. All help, big or small, is
+more than welcomed!
 
-### Ask questions
+## Ask questions
 
-Any question you may have, somebody else might have it too. Always feel
-free to ask them on the [issues tracker][issues-tracker].  We will try to
-answer them as clearly and quickly as possible, time permitting.
+Any question you may have, somebody else might have it too. Always feel free to
+ask them on the [discussion board][discussions]. We will try to answer them as
+clearly and quickly as possible, time permitting.
 
 Asking questions also helps us identify areas where the documentation needs
 improvement, or new features that weren't envisioned before. Sometimes, a
-seemingly innocent question leads to the fix of a bug. Don't hesitate and
-ask away!
+seemingly innocent question leads to the fix of a bug. Don't hesitate and ask
+away!
 
-### Improve the documentation
+[discussions]: https://github.com/pelletier/go-toml/discussions
 
-The best way to share your knowledge and experience with go-toml is to
-improve the documentation. Fix a typo, clarify an interface, add an
-example, anything goes!
+## Improve the documentation
 
-The documentation is present in the [README][readme] and thorough the
-source code. On release, it gets updated on [pkg.go.dev][pkg.go.dev]. To make a
-change to the documentation, create a pull request with your proposed
-changes. For simple changes like that, the easiest way to go is probably
-the "Fork this project and edit the file" button on Github, displayed at
-the top right of the file. Unless it's a trivial change (for example a
-typo), provide a little bit of context in your pull request description or
-commit message.
+The best way to share your knowledge and experience with go-toml is to improve
+the documentation. Fix a typo, clarify an interface, add an example, anything
+goes!
 
-### Report a bug
+The documentation is present in the [README][readme] and thorough the source
+code. On release, it gets updated on [pkg.go.dev][pkg.go.dev]. To make a change
+to the documentation, create a pull request with your proposed changes. For
+simple changes like that, the easiest way to go is probably the "Fork this
+project and edit the file" button on Github, displayed at the top right of the
+file. Unless it's a trivial change (for example a typo), provide a little bit of
+context in your pull request description or commit message.
 
-Found a bug! Sorry to hear that :(. Help us and other track them down and
-fix by reporting it. [File a new bug report][bug-report] on the [issues
-tracker][issues-tracker]. The template should provide enough guidance on
-what to include. When in doubt: add more details! By reducing ambiguity and
-providing more information, it decreases back and forth and saves everyone
-time.
+## Report a bug
 
-### Code changes
+Found a bug! Sorry to hear that :(. Help us and other track them down and fix by
+reporting it. [File a new bug report][bug-report] on the [issues
+tracker][issues-tracker]. The template should provide enough guidance on what to
+include. When in doubt: add more details! By reducing ambiguity and providing
+more information, it decreases back and forth and saves everyone time.
+
+## Code changes
 
 Want to contribute a patch? Very happy to hear that!
 
 First, some high-level rules:
 
-* A short proposal with some POC code is better than a lengthy piece of
-  text with no code. Code speaks louder than words.
-* No backward-incompatible patch will be accepted unless discussed.
-  Sometimes it's hard, and Go's lack of versioning by default does not
-  help, but we try not to break people's programs unless we absolutely have
+- A short proposal with some POC code is better than a lengthy piece of text
+  with no code. Code speaks louder than words. That being said, bigger changes
+  should probably start with a [discussion][discussions].
+- No backward-incompatible patch will be accepted unless discussed. Sometimes
+  it's hard, but we try not to break people's programs unless we absolutely have
   to.
-* If you are writing a new feature or extending an existing one, make sure
-  to write some documentation.
-* Bug fixes need to be accompanied with regression tests.
-* New code needs to be tested.
-* Your commit messages need to explain why the change is needed, even if
-  already included in the PR description.
+- If you are writing a new feature or extending an existing one, make sure to
+  write some documentation.
+- Bug fixes need to be accompanied with regression tests.
+- New code needs to be tested.
+- Your commit messages need to explain why the change is needed, even if already
+  included in the PR description.
 
-It does sound like a lot, but those best practices are here to save time
-overall and continuously improve the quality of the project, which is
-something everyone benefits from.
+It does sound like a lot, but those best practices are here to save time overall
+and continuously improve the quality of the project, which is something everyone
+benefits from.
 
-#### Get started
+### Get started
 
 The fairly standard code contribution process looks like that:
 
@@ -76,42 +76,92 @@ The fairly standard code contribution process looks like that:
 2. Make your changes, commit on any branch you like.
 3. [Open up a pull request][pull-request]
 4. Review, potential ask for changes.
-5. Merge. You're in!
+5. Merge.
 
 Feel free to ask for help! You can create draft pull requests to gather
 some early feedback!
 
-#### Run the tests
+### Run the tests
 
-You can run tests for go-toml using Go's test tool: `go test ./...`.
-When creating a pull requests, all tests will be ran on Linux on a few Go
-versions (Travis CI), and on Windows using the latest Go version
-(AppVeyor).
+You can run tests for go-toml using Go's test tool: `go test -race ./...`.
 
-#### Style
+During the pull request process, all tests will be ran on Linux, Windows, and
+MacOS on the last two versions of Go.
 
-Try to look around and follow the same format and structure as the rest of
-the code. We enforce using `go fmt` on the whole code base.
+However, given GitHub's new policy to _not_ run Actions on pull requests until a
+maintainer clicks on button, it is highly recommended that you run them locally
+as you make changes.
+
+### Check coverage
+
+We use `go tool cover` to compute test coverage. Most code editors have a way to
+run and display code coverage, but at the end of the day, we do this:
+
+```
+go test -covermode=atomic -coverprofile=coverage.out
+go tool cover -func=coverage.out
+```
+
+and verify that the overall percentage of tested code does not go down. This is
+a requirement. As a rule of thumb, all lines of code touched by your changes
+should be covered. On Unix you can use `./ci.sh coverage -d v2` to check if your
+code lowers the coverage.
+
+### Verify performance
+
+Go-toml aims to stay efficient. We rely on a set of scenarios executed with Go's
+builtin benchmark systems. Because of their noisy nature, containers provided by
+Github Actions cannot be reliably used for benchmarking. As a result, you are
+responsible for checking that your changes do not incur a performance penalty.
+You can run their following to execute benchmarks:
+
+```
+go test ./... -bench=. -count=10
+```
+
+Benchmark results should be compared against each other with
+[benchstat][benchstat]. Typical flow looks like this:
+
+1. On the `v2` branch, run `go test ./... -bench=. -count 10` and save output to
+   a file (for example `old.txt`).
+2. Make some code changes.
+3. Run `go test ....` again, and save the output to an other file (for example
+   `new.txt`).
+4. Run `benchstat old.txt new.txt` to check that time/op does not go up in any
+   test.
+
+On Unix you can use `./ci.sh benchmark -d v2` to verify how your code impacts
+performance.
+
+It is highly encouraged to add the benchstat results to your pull request
+description. Pull requests that lower performance will receive more scrutiny.
+
+[benchstat]: https://pkg.go.dev/golang.org/x/perf/cmd/benchstat
+
+### Style
+
+Try to look around and follow the same format and structure as the rest of the
+code. We enforce using `go fmt` on the whole code base.
 
 ---
 
-### Maintainers-only
+## Maintainers-only
 
-#### Merge pull request
+### Merge pull request
 
 Checklist:
 
-* Passing CI.
-* Does not introduce backward-incompatible changes (unless discussed).
-* Has relevant doc changes.
-* Has relevant unit tests.
+- Passing CI.
+- Does not introduce backward-incompatible changes (unless discussed).
+- Has relevant doc changes.
+- Benchstat does not show performance regression.
 
 1. Merge using "squash and merge".
 2. Make sure to edit the commit message to keep all the useful information
    nice and clean.
 3. Make sure the commit title is clear and contains the PR number (#123).
 
-#### New release
+### New release
 
 1. Go to [releases][releases]. Click on "X commits to master since this
    release".

ci.sh

@@ -0,0 +1,162 @@
+#!/usr/bin/env bash
+
+
+stderr() {
+    echo "$@" 1>&2
+}
+
+usage() {
+    b=$(basename "$0")
+    echo $b: ERROR: "$@" 1>&2
+
+    cat 1>&2 <<EOF
+
+DESCRIPTION
+
+    $(basename "$0") is the script to run continuous integration commands for
+    go-toml on unix.
+
+    Requires Go and Git to be available in the PATH. Expects to be ran from the
+    root of go-toml's Git repository.
+
+USAGE
+
+    $b COMMAND [OPTIONS...]
+
+COMMANDS
+
+benchmark [OPTIONS...] [BRANCH]
+
+    Run benchmarks.
+
+    ARGUMENTS
+
+        BRANCH Optional. Defines which Git branch to use when running
+               benchmarks.
+
+    OPTIONS
+
+        -d      Compare benchmarks of HEAD with BRANCH using benchstats. In
+                this form the BRANCH argument is required.
+
+coverage [OPTIONS...] [BRANCH]
+
+    Generates code coverage.
+
+    ARGUMENTS
+
+        BRANCH  Optional. Defines which Git branch to use when reporting
+                coverage. Defaults to HEAD.
+
+    OPTIONS
+
+        -d      Compare coverage of HEAD with the one of BRANCH. In this form,
+                the BRANCH argument is required. Exit code is non-zero when
+                coverage percentage decreased.
+EOF
+    exit 1
+}
+
+cover() {
+    branch="${1}"
+    dir="$(mktemp -d)"
+
+    stderr "Executing coverage for ${branch} at ${dir}"
+
+    if [ "${branch}" = "HEAD" ]; then
+	    cp -r . "${dir}/"
+    else
+	    git worktree add "$dir" "$branch"
+    fi
+
+    pushd "$dir"
+    go test -covermode=atomic -coverprofile=coverage.out ./...
+    go tool cover -func=coverage.out
+    popd
+
+    if [ "${branch}" != "HEAD" ]; then
+	    git worktree remove --force "$dir"
+    fi
+}
+
+coverage() {
+    case "$1" in
+	-d)
+	    shift
+	    target="${1?Need to provide a target branch argument}"
+
+	    output_dir="$(mktemp -d)"
+	    target_out="${output_dir}/target.txt"
+	    head_out="${output_dir}/head.txt"
+	    
+	    cover "${target}" > "${target_out}"
+	    cover "HEAD" > "${head_out}"
+
+	    cat "${target_out}"
+	    cat "${head_out}"
+
+	    echo ""
+
+	    target_pct="$(cat ${target_out} |sed -E 's/.*total.*\t([0-9.]+)%/\1/;t;d')"
+	    head_pct="$(cat ${head_out} |sed -E 's/.*total.*\t([0-9.]+)%/\1/;t;d')"
+	    echo "Results: ${target} ${target_pct}% HEAD ${head_pct}%"
+
+	    delta_pct=$(echo "$head_pct - $target_pct" | bc -l)
+	    echo "Delta: ${delta_pct}"
+
+	    if [[ $delta_pct = \-* ]]; then
+		echo "Regression!";
+		return 1
+	    fi
+	    return 0
+	    ;;
+    esac
+
+    cover "${1-HEAD}"
+}
+
+bench() {
+    branch="${1}"
+    out="${2}"
+    dir="$(mktemp -d)"
+
+    stderr "Executing benchmark for ${branch} at ${dir}"
+
+    if [ "${branch}" = "HEAD" ]; then
+    	cp -r . "${dir}/"
+    else
+	    git worktree add "$dir" "$branch"
+    fi
+
+    pushd "$dir"
+    go test -bench=. -count=10 ./... | tee "${out}"
+    popd
+
+    if [ "${branch}" != "HEAD" ]; then
+	    git worktree remove --force "$dir"
+    fi
+}
+
+benchmark() {
+    case "$1" in
+    -d)
+        shift
+     	target="${1?Need to provide a target branch argument}"
+        old=`mktemp`
+        bench "${target}" "${old}"
+
+        new=`mktemp`
+        bench HEAD "${new}"
+        benchstat "${old}" "${new}"
+        return 0
+        ;;
+    esac
+
+    bench "${1-HEAD}" `mktemp`
+}
+
+case "$1" in
+    coverage) shift; coverage $@;;
+    benchmark) shift; benchmark $@;;
+    *) usage "bad argument $1";;
+esac

decode.go

@@ -1,6 +1,7 @@
 package toml
 
 import (
+	"fmt"
 	"math"
 	"strconv"
 	"time"
@@ -16,7 +17,7 @@ func parseInteger(b []byte) (int64, error) {
 		case 'o':
 			return parseIntOct(b)
 		default:
-			return 0, newDecodeError(b[1:2], "invalid base: '%c'", b[1])
+			panic(fmt.Errorf("invalid base '%c', should have been checked by scanIntOrFloat", b[1]))
 		}
 	}
 
@@ -34,41 +35,26 @@ func parseLocalDate(b []byte) (LocalDate, error) {
 		return date, newDecodeError(b, "dates are expected to have the format YYYY-MM-DD")
 	}
 
-	var err error
+	date.Year = parseDecimalDigits(b[0:4])
 
-	date.Year, err = parseDecimalDigits(b[0:4])
-	if err != nil {
-		return date, err
-	}
-
-	v, err := parseDecimalDigits(b[5:7])
-	if err != nil {
-		return date, err
-	}
+	v := parseDecimalDigits(b[5:7])
 
 	date.Month = time.Month(v)
 
-	date.Day, err = parseDecimalDigits(b[8:10])
-	if err != nil {
-		return date, err
-	}
+	date.Day = parseDecimalDigits(b[8:10])
 
 	return date, nil
 }
 
-func parseDecimalDigits(b []byte) (int, error) {
+func parseDecimalDigits(b []byte) int {
 	v := 0
 
-	for i, c := range b {
-		if !isDigit(c) {
-			return 0, newDecodeError(b[i:i+1], "should be a digit (0-9)")
-		}
-
+	for _, c := range b {
 		v *= 10
 		v += int(c - '0')
 	}
 
-	return v, nil
+	return v
 }
 
 func parseDateTime(b []byte) (time.Time, error) {
@@ -77,8 +63,6 @@ func parseDateTime(b []byte) (time.Time, error) {
 	// time-offset    = "Z" / time-numoffset
 	// time-numoffset = ( "+" / "-" ) time-hour ":" time-minute
 
-	originalBytes := b
-
 	dt, b, err := parseLocalDateTime(b)
 	if err != nil {
 		return time.Time{}, err
@@ -87,7 +71,8 @@ func parseDateTime(b []byte) (time.Time, error) {
 	var zone *time.Location
 
 	if len(b) == 0 {
-		return time.Time{}, newDecodeError(originalBytes, "date-time is missing timezone")
+		// parser should have checked that when assigning the date time node
+		panic("date time should have a timezone")
 	}
 
 	if b[0] == 'Z' {
@@ -99,18 +84,15 @@ func parseDateTime(b []byte) (time.Time, error) {
 			return time.Time{}, newDecodeError(b, "invalid date-time timezone")
 		}
 		direction := 1
-		switch b[0] {
-		case '+':
-		case '-':
+		if b[0] == '-' {
 			direction = -1
-		default:
-			return time.Time{}, newDecodeError(b[0:1], "invalid timezone offset character")
 		}
 
 		hours := digitsToInt(b[1:3])
 		minutes := digitsToInt(b[4:6])
 		seconds := direction * (hours*3600 + minutes*60)
 		zone = time.FixedZone("", seconds)
+		b = b[dateTimeByteLen:]
 	}
 
 	if len(b) > 0 {
@@ -161,7 +143,6 @@ func parseLocalDateTime(b []byte) (LocalDateTime, []byte, error) {
 // parseLocalTime is a bit different because it also returns the remaining
 // []byte that is didn't need. This is to allow parseDateTime to parse those
 // remaining bytes as a timezone.
-//nolint:cyclop,funlen
 func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 	var (
 		nspow = [10]int{0, 1e8, 1e7, 1e6, 1e5, 1e4, 1e3, 1e2, 1e1, 1e0}
@@ -173,46 +154,26 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 		return t, nil, newDecodeError(b, "times are expected to have the format HH:MM:SS[.NNNNNN]")
 	}
 
-	var err error
-
-	t.Hour, err = parseDecimalDigits(b[0:2])
-	if err != nil {
-		return t, nil, err
-	}
-
+	t.Hour = parseDecimalDigits(b[0:2])
 	if b[2] != ':' {
 		return t, nil, newDecodeError(b[2:3], "expecting colon between hours and minutes")
 	}
 
-	t.Minute, err = parseDecimalDigits(b[3:5])
-	if err != nil {
-		return t, nil, err
-	}
-
+	t.Minute = parseDecimalDigits(b[3:5])
 	if b[5] != ':' {
 		return t, nil, newDecodeError(b[5:6], "expecting colon between minutes and seconds")
 	}
 
-	t.Second, err = parseDecimalDigits(b[6:8])
-	if err != nil {
-		return t, nil, err
-	}
+	t.Second = parseDecimalDigits(b[6:8])
 
-	if len(b) >= 9 && b[8] == '.' {
+	const minLengthWithFrac = 9
+	if len(b) >= minLengthWithFrac && b[minLengthWithFrac-1] == '.' {
 		frac := 0
 		digits := 0
 
-		for i, c := range b[9:] {
-			if !isDigit(c) {
-				if i == 0 {
-					return t, nil, newDecodeError(b[i:i+1], "need at least one digit after fraction point")
-				}
-
-				break
-			}
-
-			//nolint:gomnd
-			if i >= 9 {
+		for i, c := range b[minLengthWithFrac:] {
+			const maxFracPrecision = 9
+			if i >= maxFracPrecision {
 				return t, nil, newDecodeError(b[i:i+1], "maximum precision for date time is nanosecond")
 			}
 
@@ -231,8 +192,6 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 
 //nolint:cyclop
 func parseFloat(b []byte) (float64, error) {
-	//nolint:godox
-	// TODO: inefficient
 	if len(b) == 4 && (b[0] == '+' || b[0] == '-') && b[1] == 'n' && b[2] == 'a' && b[3] == 'n' {
 		return math.NaN(), nil
 	}
@@ -252,7 +211,7 @@ func parseFloat(b []byte) (float64, error) {
 
 	f, err := strconv.ParseFloat(string(cleaned), 64)
 	if err != nil {
-		return 0, newDecodeError(b, "coudn't parse float: %w", err)
+		return 0, newDecodeError(b, "unable to parse float: %w", err)
 	}
 
 	return f, nil
@@ -315,10 +274,6 @@ func parseIntDec(b []byte) (int64, error) {
 }
 
 func checkAndRemoveUnderscores(b []byte) ([]byte, error) {
-	if len(b) == 0 {
-		return b, nil
-	}
-
 	if b[0] == '_' {
 		return nil, newDecodeError(b[0:1], "number cannot start with underscore")
 	}

doc.go

@@ -1,4 +1,2 @@
-/*
-   Package toml is a library to read and write TOML documents.
-*/
+// Package toml is a library to read and write TOML documents.
 package toml

errors.go

@@ -105,13 +105,9 @@ func (e *DecodeError) Key() Key {
 // highlight can be freely deallocated.
 //nolint:funlen
 func wrapDecodeError(document []byte, de *decodeError) *DecodeError {
-	if de == nil {
-		return nil
-	}
-
 	offset := unsafe.SubsliceOffset(document, de.highlight)
 
-	errMessage := de.message
+	errMessage := de.Error()
 	errLine, errColumn := positionAtEnd(document[:offset])
 	before, after := linesOfContext(document, de.highlight, offset, 3)
 

errors_test.go

@@ -181,6 +181,24 @@ line 5`,
 	}
 }
 
+func TestDecodeError_Accessors(t *testing.T) {
+	t.Parallel()
+
+	e := DecodeError{
+		message: "foo",
+		line:    1,
+		column:  2,
+		key:     []string{"one", "two"},
+		human:   "bar",
+	}
+	assert.Equal(t, "toml: foo", e.Error())
+	r, c := e.Position()
+	assert.Equal(t, 1, r)
+	assert.Equal(t, 2, c)
+	assert.Equal(t, Key{"one", "two"}, e.Key())
+	assert.Equal(t, "bar", e.String())
+}
+
 func ExampleDecodeError() {
 	doc := `name = 123__456`
 
@@ -189,14 +207,15 @@ func ExampleDecodeError() {
 
 	fmt.Println(err)
 
+	//nolint:errorlint
 	de := err.(*DecodeError)
 	fmt.Println(de.String())
 
 	row, col := de.Position()
-	fmt.Println("error occured at row", row, "column", col)
+	fmt.Println("error occurred at row", row, "column", col)
 	// Output:
 	// toml: number must have at least one digit between underscores
 	// 1| name = 123__456
 	//  |           ~~ number must have at least one digit between underscores
-	// error occured at row 1 column 11
+	// error occurred at row 1 column 11
 }

marshaler.go

@@ -127,6 +127,10 @@ func (enc *Encoder) Encode(v interface{}) error {
 
 	ctx.inline = enc.tablesInline
 
+	if v == nil {
+		return fmt.Errorf("toml: cannot encode a nil interface")
+	}
+
 	b, err := enc.encode(b, ctx, reflect.ValueOf(v))
 	if err != nil {
 		return err
@@ -193,10 +197,12 @@ func (ctx *encoderCtx) isRoot() bool {
 
 //nolint:cyclop,funlen
 func (enc *Encoder) encode(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, error) {
+	if !v.IsZero() {
 		i, ok := v.Interface().(time.Time)
 		if ok {
 			return i.AppendFormat(b, time.RFC3339), nil
 		}
+	}
 
 	if v.Type().Implements(textMarshalerType) {
 		if ctx.isRoot() {
@@ -273,11 +279,6 @@ func (enc *Encoder) encodeKv(b []byte, ctx encoderCtx, options valueOptions, v r
 	if !ctx.hasKey {
 		panic("caller of encodeKv should have set the key in the context")
 	}
-
-	if isNil(v) {
-		return b, nil
-	}
-
 	b = enc.indent(ctx.indent, b)
 
 	b, err = enc.encodeKey(b, ctx.key)
@@ -470,12 +471,7 @@ func (enc *Encoder) encodeMap(b []byte, ctx encoderCtx, v reflect.Value) ([]byte
 			continue
 		}
 
-		table, err := willConvertToTableOrArrayTable(ctx, v)
-		if err != nil {
-			return nil, err
-		}
-
-		if table {
+		if willConvertToTableOrArrayTable(ctx, v) {
 			t.pushTable(k, v, emptyValueOptions)
 		} else {
 			t.pushKV(k, v, emptyValueOptions)
@@ -543,18 +539,13 @@ func (enc *Encoder) encodeStruct(b []byte, ctx encoderCtx, v reflect.Value) ([]b
 			continue
 		}
 
-		willConvert, err := willConvertToTableOrArrayTable(ctx, f)
-		if err != nil {
-			return nil, err
-		}
-
 		options := valueOptions{
 			multiline: fieldBoolTag(fieldType, "multiline"),
 		}
 
 		inline := fieldBoolTag(fieldType, "inline")
 
-		if inline || !willConvert {
+		if inline || !willConvertToTableOrArrayTable(ctx, f) {
 			t.pushKV(k, f, options)
 		} else {
 			t.pushTable(k, f, options)
@@ -640,21 +631,8 @@ func (enc *Encoder) encodeTableInline(b []byte, ctx encoderCtx, t table) ([]byte
 		}
 	}
 
-	for _, table := range t.tables {
-		if first {
-			first = false
-		} else {
-			b = append(b, `, `...)
-		}
-
-		ctx.setKey(table.Key)
-
-		b, err = enc.encode(b, ctx, table.Value)
-		if err != nil {
-			return nil, err
-		}
-
-		b = append(b, '\n')
+	if len(t.tables) > 0 {
+		panic("inline table cannot contain nested tables, online key-values")
 	}
 
 	b = append(b, "}"...)
@@ -664,61 +642,50 @@ func (enc *Encoder) encodeTableInline(b []byte, ctx encoderCtx, t table) ([]byte
 
 var textMarshalerType = reflect.TypeOf(new(encoding.TextMarshaler)).Elem()
 
-func willConvertToTable(ctx encoderCtx, v reflect.Value) (bool, error) {
+func willConvertToTable(ctx encoderCtx, v reflect.Value) bool {
 	if v.Type() == timeType || v.Type().Implements(textMarshalerType) {
-		return false, nil
+		return false
 	}
 
 	t := v.Type()
 	switch t.Kind() {
 	case reflect.Map, reflect.Struct:
-		return !ctx.inline, nil
+		return !ctx.inline
 	case reflect.Interface:
-		if v.IsNil() {
-			return false, fmt.Errorf("toml: encoding a nil interface is not supported")
-		}
-
 		return willConvertToTable(ctx, v.Elem())
 	case reflect.Ptr:
 		if v.IsNil() {
-			return false, nil
+			return false
 		}
 
 		return willConvertToTable(ctx, v.Elem())
 	default:
-		return false, nil
+		return false
 	}
 }
 
-func willConvertToTableOrArrayTable(ctx encoderCtx, v reflect.Value) (bool, error) {
+func willConvertToTableOrArrayTable(ctx encoderCtx, v reflect.Value) bool {
 	t := v.Type()
 
 	if t.Kind() == reflect.Interface {
-		if v.IsNil() {
-			return false, fmt.Errorf("toml: encoding a nil interface is not supported")
-		}
-
 		return willConvertToTableOrArrayTable(ctx, v.Elem())
 	}
 
 	if t.Kind() == reflect.Slice {
 		if v.Len() == 0 {
 			// An empty slice should be a kv = [].
-			return false, nil
+			return false
 		}
 
 		for i := 0; i < v.Len(); i++ {
-			t, err := willConvertToTable(ctx, v.Index(i))
-			if err != nil {
-				return false, err
-			}
+			t := willConvertToTable(ctx, v.Index(i))
 
 			if !t {
-				return false, nil
+				return false
 			}
 		}
 
-		return true, nil
+		return true
 	}
 
 	return willConvertToTable(ctx, v)
@@ -731,12 +698,7 @@ func (enc *Encoder) encodeSlice(b []byte, ctx encoderCtx, v reflect.Value) ([]by
 		return b, nil
 	}
 
-	allTables, err := willConvertToTableOrArrayTable(ctx, v)
-	if err != nil {
-		return nil, err
-	}
-
-	if allTables {
+	if willConvertToTableOrArrayTable(ctx, v) {
 		return enc.encodeSliceAsArrayTable(b, ctx, v)
 	}
 
@@ -746,10 +708,6 @@ func (enc *Encoder) encodeSlice(b []byte, ctx encoderCtx, v reflect.Value) ([]by
 // caller should have checked that v is a slice that only contains values that
 // encode into tables.
 func (enc *Encoder) encodeSliceAsArrayTable(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, error) {
-	if v.Len() == 0 {
-		return b, nil
-	}
-
 	ctx.shiftKey()
 
 	var err error

marshaler_test.go

@@ -16,6 +16,12 @@ import (
 func TestMarshal(t *testing.T) {
 	t.Parallel()
 
+	someInt := 42
+
+	type structInline struct {
+		A interface{} `inline:"true"`
+	}
+
 	examples := []struct {
 		desc     string
 		v        interface{}
@@ -298,6 +304,213 @@ A = [
 ]
 `,
 		},
+		{
+			desc: "nil interface not supported at root",
+			v:    nil,
+			err:  true,
+		},
+		{
+			desc: "nil interface not supported in slice",
+			v: map[string]interface{}{
+				"a": []interface{}{"a", nil, 2},
+			},
+			err: true,
+		},
+		{
+			desc: "nil pointer in slice uses zero value",
+			v: struct {
+				A []*int
+			}{
+				A: []*int{nil},
+			},
+			expected: `A = [0]`,
+		},
+		{
+			desc: "nil pointer in slice uses zero value",
+			v: struct {
+				A []*int
+			}{
+				A: []*int{nil},
+			},
+			expected: `A = [0]`,
+		},
+		{
+			desc: "pointer in slice",
+			v: struct {
+				A []*int
+			}{
+				A: []*int{&someInt},
+			},
+			expected: `A = [42]`,
+		},
+		{
+			desc: "inline table in inline table",
+			v: structInline{
+				A: structInline{
+					A: structInline{
+						A: "hello",
+					},
+				},
+			},
+			expected: `A = {A = {A = 'hello'}}`,
+		},
+		{
+			desc: "empty slice in map",
+			v: map[string][]string{
+				"a": {},
+			},
+			expected: `a = []`,
+		},
+		{
+			desc: "map in slice",
+			v: map[string][]map[string]string{
+				"a": {{"hello": "world"}},
+			},
+			expected: `
+[[a]]
+hello = 'world'`,
+		},
+		{
+			desc: "newline in map in slice",
+			v: map[string][]map[string]string{
+				"a\n": {{"hello": "world"}},
+			},
+			err: true,
+		},
+		{
+			desc: "newline in map in slice",
+			v: map[string][]map[string]*customTextMarshaler{
+				"a": {{"hello": &customTextMarshaler{1}}},
+			},
+			err: true,
+		},
+		{
+			desc: "empty slice of empty struct",
+			v: struct {
+				A []struct{}
+			}{
+				A: []struct{}{},
+			},
+			expected: `A = []`,
+		},
+		{
+			desc: "nil field is ignored",
+			v: struct {
+				A interface{}
+			}{
+				A: nil,
+			},
+			expected: ``,
+		},
+		{
+			desc: "private fields are ignored",
+			v: struct {
+				Public  string
+				private string
+			}{
+				Public:  "shown",
+				private: "hidden",
+			},
+			expected: `Public = 'shown'`,
+		},
+		{
+			desc: "fields tagged - are ignored",
+			v: struct {
+				Public  string `toml:"-"`
+				private string
+			}{
+				Public: "hidden",
+			},
+			expected: ``,
+		},
+		{
+			desc: "nil value in map is ignored",
+			v: map[string]interface{}{
+				"A": nil,
+			},
+			expected: ``,
+		},
+		{
+			desc: "new line in table key",
+			v: map[string]interface{}{
+				"hello\nworld": 42,
+			},
+			err: true,
+		},
+		{
+			desc: "new line in parent of nested table key",
+			v: map[string]interface{}{
+				"hello\nworld": map[string]interface{}{
+					"inner": 42,
+				},
+			},
+			err: true,
+		},
+		{
+			desc: "new line in nested table key",
+			v: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"in\ner": map[string]interface{}{
+						"foo": 42,
+					},
+				},
+			},
+			err: true,
+		},
+		{
+			desc: "invalid map key",
+			v:    map[int]interface{}{},
+			err:  true,
+		},
+		{
+			desc: "unhandled type",
+			v: struct {
+				A chan int
+			}{
+				A: make(chan int),
+			},
+			err: true,
+		},
+		{
+			desc: "numbers",
+			v: struct {
+				A float32
+				B uint64
+				C uint32
+				D uint16
+				E uint8
+				F uint
+				G int64
+				H int32
+				I int16
+				J int8
+				K int
+			}{
+				A: 1.1,
+				B: 42,
+				C: 42,
+				D: 42,
+				E: 42,
+				F: 42,
+				G: 42,
+				H: 42,
+				I: 42,
+				J: 42,
+				K: 42,
+			},
+			expected: `
+A = 1.1
+B = 42
+C = 42
+D = 42
+E = 42
+F = 42
+G = 42
+H = 42
+I = 42
+J = 42
+K = 42`,
+		},
 	}
 
 	for _, e := range examples {
@@ -460,6 +673,85 @@ root = 'value0'
 	}
 }
 
+type customTextMarshaler struct {
+	value int64
+}
+
+func (c *customTextMarshaler) MarshalText() ([]byte, error) {
+	if c.value == 1 {
+		return nil, fmt.Errorf("cannot represent 1 because this is a silly test")
+	}
+	return []byte(fmt.Sprintf("::%d", c.value)), nil
+}
+
+func TestMarshalTextMarshaler_NoRoot(t *testing.T) {
+	t.Parallel()
+
+	c := customTextMarshaler{}
+	_, err := toml.Marshal(&c)
+	require.Error(t, err)
+}
+
+func TestMarshalTextMarshaler_Error(t *testing.T) {
+	t.Parallel()
+
+	m := map[string]interface{}{"a": &customTextMarshaler{value: 1}}
+	_, err := toml.Marshal(m)
+	require.Error(t, err)
+}
+
+func TestMarshalTextMarshaler_ErrorInline(t *testing.T) {
+	t.Parallel()
+
+	type s struct {
+		A map[string]interface{} `inline:"true"`
+	}
+
+	d := s{
+		A: map[string]interface{}{"a": &customTextMarshaler{value: 1}},
+	}
+
+	_, err := toml.Marshal(d)
+	require.Error(t, err)
+}
+
+func TestMarshalTextMarshaler(t *testing.T) {
+	t.Parallel()
+
+	m := map[string]interface{}{"a": &customTextMarshaler{value: 2}}
+	r, err := toml.Marshal(m)
+	require.NoError(t, err)
+	equalStringsIgnoreNewlines(t, "a = '::2'", string(r))
+}
+
+type brokenWriter struct{}
+
+func (b *brokenWriter) Write([]byte) (int, error) {
+	return 0, fmt.Errorf("dead")
+}
+
+func TestEncodeToBrokenWriter(t *testing.T) {
+	t.Parallel()
+	w := brokenWriter{}
+	enc := toml.NewEncoder(&w)
+	err := enc.Encode(map[string]string{"hello": "world"})
+	require.Error(t, err)
+}
+
+func TestEncoderSetIndentSymbol(t *testing.T) {
+	t.Parallel()
+	var w strings.Builder
+	enc := toml.NewEncoder(&w)
+	enc.SetIndentTables(true)
+	enc.SetIndentSymbol(">>>")
+	err := enc.Encode(map[string]map[string]string{"parent": {"hello": "world"}})
+	require.NoError(t, err)
+	expected := `
+[parent]
+>>>hello = 'world'`
+	equalStringsIgnoreNewlines(t, expected, w.String())
+}
+
 func TestIssue436(t *testing.T) {
 	t.Parallel()
 

parser.go

@@ -2,7 +2,6 @@ package toml
 
 import (
 	"bytes"
-	"fmt"
 	"strconv"
 
 	"github.com/pelletier/go-toml/v2/internal/ast"
@@ -77,7 +76,6 @@ func (p *parser) parseNewline(b []byte) ([]byte, error) {
 
 	if b[0] == '\r' {
 		_, rest, err := scanWindowsNewline(b)
-
 		return rest, err
 	}
 
@@ -206,6 +204,10 @@ func (p *parser) parseKeyval(b []byte) (ast.Reference, []byte, error) {
 
 	b = p.parseWhitespace(b)
 
+	if len(b) == 0 {
+		return ast.Reference{}, nil, newDecodeError(b, "expected = after a key, but the document ends there")
+	}
+
 	b, err = expect('=', b)
 	if err != nil {
 		return ast.Reference{}, nil, err
@@ -304,6 +306,7 @@ func atmost(b []byte, n int) []byte {
 	if n >= len(b) {
 		return b
 	}
+
 	return b[:n]
 }
 
@@ -397,8 +400,7 @@ func (p *parser) parseValArray(b []byte) (ast.Reference, []byte, error) {
 		}
 
 		if len(b) == 0 {
-			//nolint:godox
-			return parent, nil, unexpectedCharacter{b: b} // TODO: should be unexpected EOF
+			return parent, nil, newDecodeError(b, "array is incomplete")
 		}
 
 		if b[0] == ']' {
@@ -562,7 +564,7 @@ func (p *parser) parseMultilineBasicString(b []byte) ([]byte, []byte, error) {
 			case 't':
 				builder.WriteByte('\t')
 			case 'u':
-				x, err := hexToString(token[i+3:len(token)-3], 4)
+				x, err := hexToString(atmost(token[i+1:], 4), 4)
 				if err != nil {
 					return nil, nil, err
 				}
@@ -570,7 +572,7 @@ func (p *parser) parseMultilineBasicString(b []byte) ([]byte, []byte, error) {
 				builder.WriteString(x)
 				i += 4
 			case 'U':
-				x, err := hexToString(token[i+3:len(token)-3], 8)
+				x, err := hexToString(atmost(token[i+1:], 8), 8)
 				if err != nil {
 					return nil, nil, err
 				}
@@ -610,12 +612,7 @@ func (p *parser) parseKey(b []byte) (ast.Reference, []byte, error) {
 	for {
 		b = p.parseWhitespace(b)
 		if len(b) > 0 && b[0] == '.' {
-			b, err = expect('.', b)
-			if err != nil {
-				return ref, nil, err
-			}
-
-			b = p.parseWhitespace(b)
+			b = p.parseWhitespace(b[1:])
 
 			key, b, err = p.parseSimpleKey(b)
 			if err != nil {
@@ -639,8 +636,7 @@ func (p *parser) parseSimpleKey(b []byte) (key, rest []byte, err error) {
 	// unquoted-key = 1*( ALPHA / DIGIT / %x2D / %x5F ) ; A-Z / a-z / 0-9 / - / _
 	// quoted-key = basic-string / literal-string
 	if len(b) == 0 {
-		//nolint:godox
-		return nil, nil, unexpectedCharacter{b: b} // TODO: should be unexpected EOF
+		return nil, nil, newDecodeError(b, "key is incomplete")
 	}
 
 	switch {
@@ -649,10 +645,10 @@ func (p *parser) parseSimpleKey(b []byte) (key, rest []byte, err error) {
 	case b[0] == '"':
 		return p.parseBasicString(b)
 	case isUnquotedKeyChar(b[0]):
-		return scanUnquotedKey(b)
+		key, rest = scanUnquotedKey(b)
+		return key, rest, nil
 	default:
-		//nolint:godox
-		return nil, nil, unexpectedCharacter{b: b} // TODO: should be unexpected EOF
+		return nil, nil, newDecodeError(b[0:1], "invalid character at start of key: %c", b[0])
 	}
 }
 
@@ -825,11 +821,14 @@ byteLoop:
 		c := b[i]
 
 		switch {
-		case isDigit(c) || c == '-':
+		case isDigit(c):
+		case c == '-':
+			const offsetOfTz = 19
+			if i == offsetOfTz {
+				hasTz = true
+			}
 		case c == 'T' || c == ':' || c == '.':
 			hasTime = true
-
-			continue byteLoop
 		case c == '+' || c == '-' || c == 'Z':
 			hasTz = true
 		case c == ' ':
@@ -854,9 +853,6 @@ byteLoop:
 			kind = ast.LocalDateTime
 		}
 	} else {
-		if hasTz {
-			return ast.Reference{}, nil, newDecodeError(b, "date-time has timezone but not time component")
-		}
 		kind = ast.LocalDate
 	}
 
@@ -977,26 +973,9 @@ func isValidBinaryRune(r byte) bool {
 }
 
 func expect(x byte, b []byte) ([]byte, error) {
-	if len(b) == 0 {
-		return nil, newDecodeError(b[:0], "expecting %#U", x)
-	}
-
 	if b[0] != x {
 		return nil, newDecodeError(b[0:1], "expected character %U", x)
 	}
 
 	return b[1:], nil
 }
-
-type unexpectedCharacter struct {
-	r byte
-	b []byte
-}
-
-func (u unexpectedCharacter) Error() string {
-	if len(u.b) == 0 {
-		return fmt.Sprintf("expected %#U, not EOF", u.r)
-	}
-
-	return fmt.Sprintf("expected %#U, not %#U", u.r, u.b[0])
-}

scanner.go

@@ -30,15 +30,15 @@ func scanFollowsNan(b []byte) bool {
 	return scanFollows(b, `nan`)
 }
 
-func scanUnquotedKey(b []byte) ([]byte, []byte, error) {
+func scanUnquotedKey(b []byte) ([]byte, []byte) {
 	// unquoted-key = 1*( ALPHA / DIGIT / %x2D / %x5F ) ; A-Z / a-z / 0-9 / - / _
 	for i := 0; i < len(b); i++ {
 		if !isUnquotedKeyChar(b[i]) {
-			return b[:i], b[i:], nil
+			return b[:i], b[i:]
 		}
 	}
 
-	return b, b[len(b):], nil
+	return b, b[len(b):]
 }
 
 func isUnquotedKeyChar(r byte) bool {

targets.go

@@ -70,19 +70,19 @@ func (t interfaceTarget) set(v reflect.Value) {
 }
 
 func (t interfaceTarget) setString(v string) {
-	t.x.setString(v)
+	panic("interface targets should always go through set")
 }
 
 func (t interfaceTarget) setBool(v bool) {
-	t.x.setBool(v)
+	panic("interface targets should always go through set")
 }
 
 func (t interfaceTarget) setInt64(v int64) {
-	t.x.setInt64(v)
+	panic("interface targets should always go through set")
 }
 
 func (t interfaceTarget) setFloat64(v float64) {
-	t.x.setFloat64(v)
+	panic("interface targets should always go through set")
 }
 
 // mapTarget targets a specific key of a map.
@@ -115,7 +115,6 @@ func (t mapTarget) setFloat64(v float64) {
 	t.set(reflect.ValueOf(v))
 }
 
-//nolint:cyclop
 // makes sure that the value pointed at by t is indexable (Slice, Array), or
 // dereferences to an indexable (Ptr, Interface).
 func ensureValueIndexable(t target) error {
@@ -193,7 +192,7 @@ const (
 	minInt = -maxInt - 1
 )
 
-//nolint:funlen,gocognit,cyclop,gocyclo
+//nolint:funlen,gocognit,cyclop
 func setInt64(t target, v int64) error {
 	f := t.get()
 
@@ -285,7 +284,6 @@ func setFloat64(t target, v float64) error {
 	return nil
 }
 
-//nolint:cyclop
 // Returns the element at idx of the value pointed at by target, or an error if
 // t does not point to an indexable.
 // If the target points to an Array and idx is out of bounds, it returns
@@ -311,7 +309,6 @@ func elementAt(t target, idx int) target {
 	case reflect.Interface:
 		// This function is called after ensureValueIndexable, so it's
 		// guaranteed that f contains an initialized slice.
-
 		ifaceElem := f.Elem()
 		idx := ifaceElem.Len()
 		newElem := reflect.New(ifaceElem.Type().Elem()).Elem()
@@ -326,7 +323,6 @@ func elementAt(t target, idx int) target {
 	}
 }
 
-//nolint:cyclop
 func (d *decoder) scopeTableTarget(shouldAppend bool, t target, name string) (target, bool, error) {
 	x := t.get()
 

unmarshaler.go

@@ -541,6 +541,27 @@ func (d *decoder) unmarshalArray(x target, node ast.Node) error {
 		return err
 	}
 
+	// Special work around when unmarshaling into an array.
+	// If the array is not addressable, for example when stored as a value in a
+	// map, calling elementAt in the inner function would fail.
+	// Instead, we allocate a new array that will be filled then inserted into
+	// the container.
+	// This problem does not exist with slices because they are addressable.
+	// There may be a better way of doing this, but it is not obvious to me
+	// with the target system.
+	if x.get().Kind() == reflect.Array {
+		container := x
+		newArrayPtr := reflect.New(x.get().Type())
+		x = valueTarget(newArrayPtr.Elem())
+		defer func() {
+			container.set(newArrayPtr.Elem())
+		}()
+	}
+
+	return d.unmarshalArrayInner(x, node)
+}
+
+func (d *decoder) unmarshalArrayInner(x target, node ast.Node) error {
 	idx := 0
 
 	it := node.Children()
@@ -555,14 +576,13 @@ func (d *decoder) unmarshalArray(x target, node ast.Node) error {
 			break
 		}
 
-		err = d.unmarshalValue(v, n)
+		err := d.unmarshalValue(v, n)
 		if err != nil {
 			return err
 		}
 
 		idx++
 	}
-
 	return nil
 }
 

unmarshaler_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// nolint:funlen
 func TestUnmarshal_Integers(t *testing.T) {
 	t.Parallel()
 
@@ -239,6 +240,34 @@ func TestUnmarshal(t *testing.T) {
 				}
 			},
 		},
+		{
+			desc:  "time.time with negative zone",
+			input: `a = 1979-05-27T00:32:00-07:00 `, // space intentional
+			gen: func() test {
+				var v map[string]time.Time
+
+				return test{
+					target: &v,
+					expected: &map[string]time.Time{
+						"a": time.Date(1979, 5, 27, 0, 32, 0, 0, time.FixedZone("", -7*3600)),
+					},
+				}
+			},
+		},
+		{
+			desc:  "time.time with positive zone",
+			input: `a = 1979-05-27T00:32:00+07:00`,
+			gen: func() test {
+				var v map[string]time.Time
+
+				return test{
+					target: &v,
+					expected: &map[string]time.Time{
+						"a": time.Date(1979, 5, 27, 0, 32, 0, 0, time.FixedZone("", 7*3600)),
+					},
+				}
+			},
+		},
 		{
 			desc: "issue 475 - space between dots in key",
 			input: `fruit. color = "yellow"
@@ -288,6 +317,73 @@ func TestUnmarshal(t *testing.T) {
 				}
 			},
 		},
+		{
+			desc:  "multiline literal string with windows newline",
+			input: "A = '''\r\nTest'''",
+			gen: func() test {
+				type doc struct {
+					A string
+				}
+
+				return test{
+					target:   &doc{},
+					expected: &doc{A: "Test"},
+				}
+			},
+		},
+		{
+			desc:  "multiline basic string with windows newline",
+			input: "A = \"\"\"\r\nTest\"\"\"",
+			gen: func() test {
+				type doc struct {
+					A string
+				}
+
+				return test{
+					target:   &doc{},
+					expected: &doc{A: "Test"},
+				}
+			},
+		},
+		{
+			desc: "multiline basic string escapes",
+			input: `A = """
+\\\b\f\n\r\t\uffff\U0001D11E"""`,
+			gen: func() test {
+				type doc struct {
+					A string
+				}
+
+				return test{
+					target:   &doc{},
+					expected: &doc{A: "\\\b\f\n\r\t\uffff\U0001D11E"},
+				}
+			},
+		},
+		{
+			desc:  "basic string escapes",
+			input: `A = "\\\b\f\n\r\t\uffff\U0001D11E"`,
+			gen: func() test {
+				type doc struct {
+					A string
+				}
+
+				return test{
+					target:   &doc{},
+					expected: &doc{A: "\\\b\f\n\r\t\uffff\U0001D11E"},
+				}
+			},
+		},
+		{
+			desc:  "spaces around dotted keys",
+			input: "a . b = 1",
+			gen: func() test {
+				return test{
+					target:   &map[string]map[string]interface{}{},
+					expected: &map[string]map[string]interface{}{"a": {"b": int64(1)}},
+				}
+			},
+		},
 		{
 			desc:  "kv bool true",
 			input: `A = true`,
@@ -721,6 +817,197 @@ B = "data"`,
 				}
 			},
 		},
+		{
+			desc:  "interface holding a string",
+			input: `A = "Hello"`,
+			gen: func() test {
+				type doc struct {
+					A interface{}
+				}
+				return test{
+					target: &doc{},
+					expected: &doc{
+						A: "Hello",
+					},
+				}
+			},
+		},
+		{
+			desc:  "map of bools",
+			input: `A = true`,
+			gen: func() test {
+				return test{
+					target:   &map[string]bool{},
+					expected: &map[string]bool{"A": true},
+				}
+			},
+		},
+		{
+			desc:  "map of int64",
+			input: `A = 42`,
+			gen: func() test {
+				return test{
+					target:   &map[string]int64{},
+					expected: &map[string]int64{"A": 42},
+				}
+			},
+		},
+		{
+			desc:  "map of float64",
+			input: `A = 4.2`,
+			gen: func() test {
+				return test{
+					target:   &map[string]float64{},
+					expected: &map[string]float64{"A": 4.2},
+				}
+			},
+		},
+		{
+			desc:  "array of int in map",
+			input: `A = [1,2,3]`,
+			gen: func() test {
+				return test{
+					target:   &map[string][3]int{},
+					expected: &map[string][3]int{"A": {1, 2, 3}},
+				}
+			},
+		},
+		{
+			desc:  "array of int in map with too many elements",
+			input: `A = [1,2,3,4,5]`,
+			gen: func() test {
+				return test{
+					target:   &map[string][3]int{},
+					expected: &map[string][3]int{"A": {1, 2, 3}},
+				}
+			},
+		},
+		{
+			desc:  "array of int in map with invalid element",
+			input: `A = [1,2,false]`,
+			gen: func() test {
+				return test{
+					target: &map[string][3]int{},
+					err:    true,
+				}
+			},
+		},
+		{
+			desc: "nested arrays",
+			input: `
+			[[A]]
+			[[A.B]]
+			C = 1
+			[[A]]
+			[[A.B]]
+			C = 2`,
+			gen: func() test {
+				type leaf struct {
+					C int
+				}
+				type inner struct {
+					B [2]leaf
+				}
+				type s struct {
+					A [2]inner
+				}
+				return test{
+					target: &s{},
+					expected: &s{A: [2]inner{
+						{B: [2]leaf{
+							{C: 1},
+						}},
+						{B: [2]leaf{
+							{C: 2},
+						}},
+					}},
+				}
+			},
+		},
+		{
+			desc: "nested arrays too many",
+			input: `
+			[[A]]
+			[[A.B]]
+			C = 1
+			[[A.B]]
+			C = 2`,
+			gen: func() test {
+				type leaf struct {
+					C int
+				}
+				type inner struct {
+					B [1]leaf
+				}
+				type s struct {
+					A [1]inner
+				}
+				return test{
+					target: &s{},
+					err:    true,
+				}
+			},
+		},
+		{
+			desc:  "into map with invalid key type",
+			input: `A = "hello"`,
+			gen: func() test {
+				return test{
+					target: &map[int]string{},
+					err:    true,
+				}
+			},
+		},
+		{
+			desc:  "into map with convertible key type",
+			input: `A = "hello"`,
+			gen: func() test {
+				type foo string
+				return test{
+					target: &map[foo]string{},
+					expected: &map[foo]string{
+						"A": "hello",
+					},
+				}
+			},
+		},
+		{
+			desc:  "array of int in struct",
+			input: `A = [1,2,3]`,
+			gen: func() test {
+				type s struct {
+					A [3]int
+				}
+				return test{
+					target:   &s{},
+					expected: &s{A: [3]int{1, 2, 3}},
+				}
+			},
+		},
+		{
+			desc: "array of int in struct",
+			input: `[A]
+			b = 42`,
+			gen: func() test {
+				type s struct {
+					A *map[string]interface{}
+				}
+				return test{
+					target:   &s{},
+					expected: &s{A: &map[string]interface{}{"b": int64(42)}},
+				}
+			},
+		},
+		{
+			desc:  "assign bool to float",
+			input: `A = true`,
+			gen: func() test {
+				return test{
+					target: &map[string]float64{},
+					err:    true,
+				}
+			},
+		},
 		{
 			desc: "interface holding a struct",
 			input: `[A]
@@ -838,15 +1125,14 @@ B = "data"`,
 		},
 		{
 			desc:  "mismatch types array of int to interface with non-slice",
-			input: `A = [[42]]`,
-			skip:  true,
+			input: `A = [42]`,
 			gen: func() test {
 				type S struct {
-					A *string
+					A string
 				}
 				return test{
 					target: &S{},
-					expected: &S{},
+					err:    true,
 				}
 			},
 		},
@@ -878,6 +1164,82 @@ B = "data"`,
 	}
 }
 
+func TestUnmarshalOverflows(t *testing.T) {
+	examples := []struct {
+		t      interface{}
+		errors []string
+	}{
+		{
+			t:      &map[string]int32{},
+			errors: []string{`-2147483649`, `2147483649`},
+		},
+		{
+			t:      &map[string]int16{},
+			errors: []string{`-2147483649`, `2147483649`},
+		},
+		{
+			t:      &map[string]int8{},
+			errors: []string{`-2147483649`, `2147483649`},
+		},
+		{
+			t:      &map[string]int{},
+			errors: []string{`-19223372036854775808`, `9223372036854775808`},
+		},
+		{
+			t:      &map[string]uint64{},
+			errors: []string{`-1`, `18446744073709551616`},
+		},
+		{
+			t:      &map[string]uint32{},
+			errors: []string{`-1`, `18446744073709551616`},
+		},
+		{
+			t:      &map[string]uint16{},
+			errors: []string{`-1`, `18446744073709551616`},
+		},
+		{
+			t:      &map[string]uint8{},
+			errors: []string{`-1`, `18446744073709551616`},
+		},
+		{
+			t:      &map[string]uint{},
+			errors: []string{`-1`, `18446744073709551616`},
+		},
+	}
+
+	for _, e := range examples {
+		e := e
+		for _, v := range e.errors {
+			v := v
+			t.Run(fmt.Sprintf("%T %s", e.t, v), func(t *testing.T) {
+				doc := "A = " + v
+				err := toml.Unmarshal([]byte(doc), e.t)
+				t.Log("input:", doc)
+				require.Error(t, err)
+			})
+		}
+		t.Run(fmt.Sprintf("%T ok", e.t), func(t *testing.T) {
+			doc := "A = 1"
+			err := toml.Unmarshal([]byte(doc), e.t)
+			t.Log("input:", doc)
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestUnmarshalFloat32(t *testing.T) {
+	t.Run("fits", func(t *testing.T) {
+		doc := "A = 1.2"
+		err := toml.Unmarshal([]byte(doc), &map[string]float32{})
+		require.NoError(t, err)
+	})
+	t.Run("overflows", func(t *testing.T) {
+		doc := "A = 4.40282346638528859811704183484516925440e+38"
+		err := toml.Unmarshal([]byte(doc), &map[string]float32{})
+		require.Error(t, err)
+	})
+}
+
 type Integer484 struct {
 	Value int
 }
@@ -1000,10 +1362,66 @@ func TestUnmarshalDecodeErrors(t *testing.T) {
 		data string
 		msg  string
 	}{
+		{
+			desc: "local date with invalid digit",
+			data: `a = 20x1-05-21`,
+		},
+		{
+			desc: "local time with fractional",
+			data: `a = 11:22:33.x`,
+		},
+		{
+			desc: "local time frac precision too large",
+			data: `a = 2021-05-09T11:22:33.99999999999`,
+		},
+		{
+			desc: "wrong time offset separator",
+			data: `a = 1979-05-27T00:32:00T07:00`,
+		},
+		{
+			desc: "wrong time offset separator",
+			data: `a = 1979-05-27T00:32:00Z07:00`,
+		},
+		{
+			desc: "float with double _",
+			data: `flt8 = 224_617.445_991__228`,
+		},
+		{
+			desc: "float with double _",
+			data: `flt8 = 1..2`,
+		},
 		{
 			desc: "int with wrong base",
 			data: `a = 0f2`,
 		},
+		{
+			desc: "int hex with double underscore",
+			data: `a = 0xFFF__FFF`,
+		},
+		{
+			desc: "int hex very large",
+			data: `a = 0xFFFFFFFFFFFFFFFFF`,
+		},
+		{
+			desc: "int oct with double underscore",
+			data: `a = 0o777__77`,
+		},
+		{
+			desc: "int oct very large",
+			data: `a = 0o77777777777777777777777`,
+		},
+		{
+			desc: "int bin with double underscore",
+			data: `a = 0b111__111`,
+		},
+		{
+			desc: "int bin very large",
+			data: `a = 0b11111111111111111111111111111111111111111111111111111111111111111111111111111`,
+		},
+		{
+			desc: "int dec very large",
+			data: `a = 999999999999999999999999`,
+		},
 		{
 			desc: "literal string with new lines",
 			data: `a = 'hello
@@ -1066,6 +1484,102 @@ world'`,
 			data: `a = 2021-03-30 21:312:0`,
 			msg:  `expecting colon between minutes and seconds`,
 		},
+		{
+			desc: `binary with invalid digit`,
+			data: `a = 0bf`,
+		},
+		{
+			desc: `invalid i in dec`,
+			data: `a = 0i`,
+		},
+		{
+			desc: `invalid n in dec`,
+			data: `a = 0n`,
+		},
+		{
+			desc: `invalid unquoted key`,
+			data: `a`,
+		},
+		{
+			desc: "dt with tz has no time",
+			data: `a = 2021-03-30TZ`,
+		},
+		{
+			desc: "invalid end of array table",
+			data: `[[a}`,
+		},
+		{
+			desc: "invalid end of array table two",
+			data: `[[a]}`,
+		},
+		{
+			desc: "eof after equal",
+			data: `a =`,
+		},
+		{
+			desc: "invalid true boolean",
+			data: `a = trois`,
+		},
+		{
+			desc: "invalid false boolean",
+			data: `a = faux`,
+		},
+		{
+			desc: "inline table with incorrect separator",
+			data: `a = {b=1;}`,
+		},
+		{
+			desc: "inline table with invalid value",
+			data: `a = {b=faux}`,
+		},
+		{
+			desc: `incomplete array after whitespace`,
+			data: `a = [ `,
+		},
+		{
+			desc: `array with comma first`,
+			data: `a = [ ,]`,
+		},
+		{
+			desc: `array staring with incomplete newline`,
+			data: "a = [\r]",
+		},
+		{
+			desc: `array with incomplete newline after comma`,
+			data: "a = [1,\r]",
+		},
+		{
+			desc: `array with incomplete newline after value`,
+			data: "a = [1\r]",
+		},
+		{
+			desc: `invalid unicode in basic multiline string`,
+			data: `A = """\u123"""`,
+		},
+		{
+			desc: `invalid long unicode in basic multiline string`,
+			data: `A = """\U0001D11"""`,
+		},
+		{
+			desc: `invalid unicode in basic string`,
+			data: `A = "\u123"`,
+		},
+		{
+			desc: `invalid long unicode in basic string`,
+			data: `A = "\U0001D11"`,
+		},
+		{
+			desc: `invalid escape char basic multiline string`,
+			data: `A = """\z"""`,
+		},
+		{
+			desc: `invalid inf`,
+			data: `A = ick`,
+		},
+		{
+			desc: `invalid nan`,
+			data: `A = non`,
+		},
 	}
 
 	for _, e := range examples {
@@ -1271,6 +1785,7 @@ bar = 42
 		t.Run(e.desc, func(t *testing.T) {
 			t.Parallel()
 
+			t.Run("strict", func(t *testing.T) {
 				r := strings.NewReader(e.input)
 				d := toml.NewDecoder(r)
 				d.SetStrict(true)
@@ -1287,6 +1802,19 @@ bar = 42
 					t.Fatalf("err should have been a *toml.StrictMissingError, but got %s (%T)", err, err)
 				}
 			})
+
+			t.Run("default", func(t *testing.T) {
+				r := strings.NewReader(e.input)
+				d := toml.NewDecoder(r)
+				d.SetStrict(false)
+				x := e.target
+				if x == nil {
+					x = &struct{}{}
+				}
+				err := d.Decode(x)
+				require.NoError(t, err)
+			})
+		})
 	}
 }