feat: Updates Go to 1.26 and refactors internal parsing

[obalunenko]

Description

This change updates the project's Go version to 1.26.2 and refactors internal environment variable parsing logic. It eliminates the use of reflection in internal/parsers.go, transitioning to a more explicit and performant approach using Go's generics. Error handling is also improved by adding specific checks for ErrInvalidValue to prevent panics and provide clearer error messages. The stretchr/testify testing library is updated, and the golang.org/x/exp/constraints dependency is removed by defining constraints directly.

Github Issue

If any, add a Github issue number.

Possible failures/side-effects

The core parsing logic has been refactored to remove reflection. While new tests specifically verify error sentinels and existing tests continue to pass, fundamental changes in type parsing could introduce unforeseen edge cases. The update to stretchr/testify might also bring subtle behavioral changes to assertions.

Other notes

• Go version 1.26.2 is now used across all GitHub Actions workflows, Makefile configuration, and Docker build environments.
• The build/docker/go-tools/Dockerfile base image is updated to v1.10.0.
• The .gitignore file now includes .vscode/ to ignore VS Code specific files.
• The README.md and getenv.go documentation clarify that empty environment variable values are treated as "not set".
• The getenv_example_test.go for url.URL now uses urlVal.String() for canonical output.
• The scripts/bump-go.sh script has been refactored for better maintainability and robustness in handling Go version updates.

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[Copilot]

Pull request overview

Updates the project’s Go toolchain version and refactors internal env parsing to remove reflection-based logic, while also refreshing vendored dependencies and tightening error sentinel behavior/documentation.

Changes:

• Bump Go version references across go.mod, CI workflows, Makefile, and build Dockerfile, and refactor scripts/bump-go.sh.
• Refactor internal numeric/complex parsing and slice parsing to use explicit generic helpers (no reflect) and adjust related tests.
• Update stretchr/testify vendoring and remove golang.org/x/exp/constraints in favor of local constraint definitions; update docs/examples accordingly.

Reviewed changes

Copilot reviewed 17 out of 36 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
vendor/modules.txt	Updates vendored module list (testify bump; removes x/exp).
vendor/golang.org/x/exp/constraints/constraints.go	Removes vendored constraints package.
vendor/golang.org/x/exp/PATENTS	Removes x/exp vendored patent notice (module removed).
vendor/golang.org/x/exp/LICENSE	Removes x/exp vendored license (module removed).
vendor/github.com/stretchr/testify/require/require_forward.go	Vendored testify updates (API/docs/forwarders).
vendor/github.com/stretchr/testify/require/require.go	Vendored testify updates (adds IsNotType; doc tweaks).
vendor/github.com/stretchr/testify/require/doc.go	Vendored testify doc update (goroutine usage note).
vendor/github.com/stretchr/testify/assert/yaml/yaml_fail.go	Vendored testify build tag cleanup.
vendor/github.com/stretchr/testify/assert/yaml/yaml_default.go	Vendored testify build tag cleanup.
vendor/github.com/stretchr/testify/assert/yaml/yaml_custom.go	Vendored testify build tag cleanup.
vendor/github.com/stretchr/testify/assert/http_assertions.go	Improves assertion error message quoting in vendored testify.
vendor/github.com/stretchr/testify/assert/doc.go	Adds brief package note in vendored testify docs.
vendor/github.com/stretchr/testify/assert/assertions.go	Vendored testify logic/doc updates (CallerInfo, Empty, JSONEq/YAMLEq shortcuts, error-chain formatting, etc.).
vendor/github.com/stretchr/testify/assert/assertion_order.go	Improves type formatting in vendored testify order assertions.
vendor/github.com/stretchr/testify/assert/assertion_forward.go	Vendored testify forwarder updates (Empty/NotEmpty/Type assertions).
vendor/github.com/stretchr/testify/assert/assertion_format.go	Vendored testify formatted assertion updates (Emptyf/IsNotTypef, etc.).
vendor/github.com/stretchr/testify/assert/assertion_compare.go	Vendored testify compare assertion message formatting refactor.
scripts/bump-go.sh	Refactors Go bump script for robustness (normalization/escaping/toolchain handling).
internal/parsers_test.go	Updates tests/benchmarks to new generic slice parser signatures.
internal/parsers.go	Removes reflection-based numeric parsing; introduces explicit parsing helpers and simpler generic slice parsing.
internal/iface_test.go	Updates parser type expectations to new generic parser types.
internal/iface.go	Updates parser implementations to align with new generic slice parsing APIs.
internal/constraint.go	Removes dependency on x/exp/constraints; defines local constraints.
internal/common_test.go	Strengthens error assertions (uses any and adds ErrorIs checks).
go.sum	Updates sums for testify bump; removes x/exp sums.
go.mod	Updates Go version and dependencies (testify bump; removes x/exp).
getenv_test.go	Adds error sentinel coverage test; improves helper to assert ErrorIs.
getenv_example_test.go	Makes URL example output canonical via url.URL.String().
getenv.go	Maps internal invalid-value errors to exported sentinel for clearer API behavior.
build/docker/go-tools/Dockerfile	Bumps go-tools base image version.
README.md	Clarifies empty env var values are treated as “not set”.
Makefile	Updates Go version used by tooling targets.
.gitignore	Ignores .vscode/.
.github/workflows/release.yml	Pins CI Go version to 1.26.2 for release workflow.
.github/workflows/go.yml	Pins CI Go version to 1.26.2 across build/test/lint/report jobs.
.github/workflows/codeql-analysis.yml	Pins CodeQL workflow Go version to 1.26.2.

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[sonarqubecloud]

Quality Gate passed

Issues
22 New issues
0 Accepted issues

Measures
0 Security Hotspots
94.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

Pull request overview

Copilot reviewed 20 out of 39 changed files in this pull request and generated 1 comment.

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[Copilot]

The go directive is now set to a specific patch version (1.26.2) and the toolchain directive was removed. In this repo the go directive previously tracked the language version (major.minor) while toolchain pinned the patch release; keeping that split avoids implying language semantics change across patch releases and aligns with Go's intended use of these directives. Consider setting go to 1.26 (or 1.26.0) and adding back toolchain go1.26.2 if you want to pin the exact toolchain version.

Suggested change

	go 1.26.2
	go 1.26
	toolchain go1.26.2