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sgdiff

package module
v0.1.0 Latest Latest
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Published: Oct 27, 2026 License: BSD-3-Clause, MIT Imports: 8 Imported by: 0

Documentation

Overview

Package sgdiff provides adapters from sourcegraph/go-diff types to diffutils.DiffContent. Use this package to parse unified diff text (standard or Git extended format) into the canonical diff types.

Index

Constants

This section is empty.

Variables

View Source
var (
	ErrMissingSentinel     = errors.New("missing required sentinel error")
	ErrTrailingKey         = errors.New("trailing key without value")
	ErrMisplacedError      = errors.New("error in wrong position")
	ErrInvalidArgumentType = errors.New("invalid argument type")
	ErrOddKeyValueCount    = errors.New("odd number of key-value arguments")
	ErrCrossPackageError   = errors.New("error from different doterr package")
)

Sentinel errors for validation failures

View Source
var (
	// ErrSgDiff is the layer sentinel for sgdiff errors.
	ErrSgDiff = errors.New("sgdiff")

	// ErrParseDiff indicates a failure to parse unified diff text.
	ErrParseDiff = errors.New("parse diff")
)

Functions

func AppendErr

func AppendErr(errs []error, err error) []error

func CombineErrs

func CombineErrs(errs []error) error

CombineErrs bundles a slice of errors into a single composite error that unwraps to its members. Order is preserved and nils are skipped. Returns nil for an empty/fully-nil slice, or the sole error when there is exactly one.

func ErrValue

func ErrValue[T any](err error, key string) (T, bool)

ErrValue extracts a single metadata value by key with type safety. Returns the value and true if found and the value is of type T. Returns the zero value of T and false if not found or type mismatch.

Example:

status, ok := ErrValue[int](err, "http_status")
if ok {
    fmt.Printf("Status: %d\n", status)
}

name, ok := ErrValue[string](err, "parameter_name")

func Errors

func Errors(err error) []error

Errors returns the errors stored on a doterr entry. If err is a doterr entry, returns its errors. If err is a joined error (has Unwrap() []error), scans immediate children left-to-right and returns errors from the first doterr entry found. Otherwise returns nil. The returned slice preserves insertion order and is a copy.

Note: These errors may be sentinel errors (e.g., ErrRepo), custom error types (e.g., *rfc9457.Error), or any other error type stored in the entry.

func FindErr

func FindErr[T error](err error) (out T, ok bool)

FindErr walks an error tree (including errors.Join trees) and returns the first match for target (via errors.As).

func MsgErr

func MsgErr(msg any) error

MsgErr creates an ad-hoc error message without requiring a sentinel error. This is a convenience for rapid development - use sentinels for production code.

Accepts two forms:

  • MsgErr("message") - creates error with the given message
  • MsgErr(err) - wraps existing error, preserving error chain for errors.Is()

Use this when you don't want to define a sentinel immediately. Future tooling can detect MsgErr usage and suggest/generate appropriate sentinel errors.

For errors with metadata, use NewErr with a sentinel, or wrap with WithErr:

err := MsgErr("config invalid")
err = WithErr(err, "path", configPath)

func NewErr

func NewErr(parts ...any) error

NewErr builds a standalone structured entry (no primary cause inside). Accepted parts:

  • error — sentinel/tag (required: at least one, must be first)
  • KV{Key,Value} — explicit key/value
  • "key", value — implicit pair (value can be any type, including error)
  • error — optional trailing cause (joined last via errors.Join)

Pattern: one or more sentinels (error), then zero or more key-value pairs, then optional trailing cause (error). After the first string key, all remaining args must form valid pairs, except for an optional final error. Returns nil if no meaningful parts are provided after validation. Returns a validation error joined with the partial entry if validation fails.

func ParseUnifiedDiff

func ParseUnifiedDiff(text string) (contents []*diffutils.DiffContent, err error)

ParseUnifiedDiff parses unified diff text (standard or Git extended) into DiffContent slices. Since unified diffs contain only hunks (not full file content), OldLines and NewLines are reconstructed from hunk data.

func ParseUnifiedDiffWithContent

func ParseUnifiedDiffWithContent(diffText string, oldFull, newFull []string) (content *diffutils.DiffContent, err error)

ParseUnifiedDiffWithContent overlays parsed hunks onto full file content, producing a DiffContent with complete OldLines and NewLines.

func WithErr

func WithErr(parts ...any) error

WithErr is a flexible enrichment helper. Typical uses:

// Enrich an existing composite error (err may be an errors.Join tree):
err = WithErr(err, "Foo", 10)

// Build an entry and join a trailing cause in one shot:
err = WithErr("endpoint", ep, ErrTemplate, cause) // 'cause' is last

Behavior:

  1. If the FIRST arg is an error, it is treated as the base error to enrich: • If it is a doterr entry, merge KVs/sentinels into that entry. • If it is a multi-unwrap (errors.Join tree), find the RIGHTMOST doterr entry, merge into it, and rebuild preserving order. • If no doterr entry is found, a new entry will be joined in (see step 3).

  2. After consuming the base (if present), if the LAST remaining arg is an error, it is treated as the CAUSE and joined LAST.

  3. The remaining middle args (if any) are collected into an entry. If we enriched an existing doterr entry in step 1, that merged entry is used; otherwise, a fresh entry is created. If there is a trailing CAUSE from step 2, the result is errors.Join(entry, cause). If there is no cause, the entry is returned.

Note: For inter-function composition, prefer New() with trailing cause:

return NewErr(ErrRepo, "key", val, cause) // cause last

Types

type ErrKV

type ErrKV interface {
	Key() string
	Value() any
}

ErrKV represents a key/value metadata pair. Keys are preserved in insertion order, and values may be of any type.

func AnyKV

func AnyKV(key string, value any) ErrKV

AnyKV creates a KV with any value type. Use this for custom types or when the specific type constructor doesn't exist.

func AppendKV

func AppendKV(kvs []ErrKV, parts ...any) []ErrKV

AppendKV appends key-value pairs to a slice of KV values. It accepts variadic arguments in three forms:

  1. Individual KV values: AppendKV(kvs, StringKV("foo", "bar"))
  2. String key-value pairs: AppendKV(kvs, "foo", "bar")
  3. Lazy ErrKV functions: AppendKV(kvs, func()ErrKV{ return StringKV("expensive", compute()) })

This function is useful for accumulating metadata throughout a function before creating an error:

var kvs []ErrKV
kvs = AppendKV(kvs, "user_id", userID)
if complexCondition {
    kvs = AppendKV(kvs, "reason", "complex")
}
return NewErr(ErrFailed, kvs, cause)

String key-value pairs must come in even counts (odd counts panic in debug mode). Lazy functions (func()ErrKV) are wrapped and not evaluated until error creation.

func BoolKV

func BoolKV(key string, value bool) ErrKV

BoolKV creates a KV with a bool value.

func ErrMeta

func ErrMeta(err error) []ErrKV

ErrMeta returns the key/value pairs stored on all doterr entries in the error tree. If err is a doterr entry, returns its metadata. If err is a joined error (has Unwrap() []error), scans all children recursively and collects metadata from all doterr entries found, preserving order. Otherwise returns nil. The returned slice preserves insertion order across all entries.

func ErrorKV

func ErrorKV(key string, value error) ErrKV

ErrorKV creates a KV with an error value. Use this when you want to include an error as metadata (not as a cause).

func Float64KV

func Float64KV(key string, value float64) ErrKV

Float64KV creates a KV with a float64 value.

func Int64KV

func Int64KV(key string, value int64) ErrKV

Int64KV creates a KV with an int64 value.

func IntKV

func IntKV(key string, value int) ErrKV

IntKV creates a KV with an int value.

func StringKV

func StringKV(key, value string) ErrKV

StringKV creates a KV with a string value.

type IsDotErrEntry

type IsDotErrEntry = interface {
	IsDotErrEntry()
	HasKV(key string, value any) bool
	MatchKV(key string, value any) bool
}

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