📦 ExtractPackageNamesFromOutput

Extracts all Composer package names of the form vendor/package from any text output, deduplicates them, and returns the list.

When to use

Use it when you have a log or command output (such as the multi-line output of install/require) and need to quickly collect all package names mentioned within. It matches Composer's package name convention with a regex and automatically deduplicates.

Signature

func ExtractPackageNamesFromOutput(output string) []string

Parameters

Parameter	Type	Description
output	string	Any command output text

Return value

• []string: the deduplicated list of package names extracted, preserving the order of first appearance; nil when there are no matches.

Example

package main

import (
	"fmt"

	"github.com/scagogogo/composer-skills/pkg/composer"
)

func main() {
	output := `Installing symfony/console (v5.4.0)
Loading from cache monolog/monolog (2.9.1)
Downloading psr/log (1.1.4)
symfony/console already installed`

	names := composer.ExtractPackageNamesFromOutput(output)
	fmt.Printf("Extracted %d package names:\n", len(names))
	for _, n := range names {
		fmt.Println("  -", n)
	}
	// Output: symfony/console, monolog/monolog, psr/log (duplicate symfony/console deduplicated)
}

Advanced

• 🔍 The regex used is ([a-z0-9]([_.-]?[a-z0-9]+)*/[a-z0-9](([_.]|-{1,2})?[a-z0-9]+)*), which conforms to the Composer package name convention (lowercase letters/digits/hyphens/underscores/dots, in vendor/package form). After FindAllString, a map is used for deduplication.
• ⚠️ The regex is case-sensitive (matches lowercase only); output containing uppercase package names will be missed. The Composer package name convention itself requires lowercase, so this usually does not matter.
• 🔗 To extract only version numbers, use ExtractVersionFromOutput.
• 📋 To parse the package list output of composer show, you can also use ParsePackageList(output) (returns []string, defined in convenience.go).