mcp: use build-time version instead of hardcoded "0.1.0"

[Ankitsinghsisodya]

Note: Re-submission of #3662, accidentally closed when the head repository was deleted.

Summary

• The MCP server advertised a static version = "0.1.0" constant to every MCP client regardless of the actual binary version, causing stale version metadata in clients that display server info.
• Replace the constant with version.Vers from pkg/version, which is already injected at build time via ldflags (-X knative.dev/func/pkg/version.Vers=$(VERS)).
• Fall back to "0.0.0+source" when the variable is empty (source builds that bypass the Makefile), consistent with how cmd/root.go handles the same case.

Changes

• pkg/mcp/mcp.go: remove const version = "0.1.0", import knative.dev/func/pkg/version, and use version.Vers (with fallback) when constructing the mcp.Implementation passed to mcp.NewServer.

Test plan

• go test ./pkg/mcp/... passes
• func version and func mcp start report the same version string
• MCP client (e.g. Claude Code) shows the correct version after func mcp start

[knative-prow]

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[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Introduces a centralized version parsing API and updates MCP/CLI version reporting to use a normalized semver string for machine consumers while preserving the original injected value for human-readable output.

Changes:

• Added pkg/version.Get() with DefaultVers fallback and semver parsing, plus unit tests.
• Updated MCP server implementation and healthcheck tool to report version.Get().String() instead of a hardcoded constant.
• Updated CLI version wiring to use version.Get().Original() and deduplicated the default version constant.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
pkg/version/version.go	Adds semver-backed version parsing with a shared fallback constant.
pkg/version/version_test.go	Adds tests for empty, injected, and invalid version behavior.
pkg/mcp/mcp.go	Replaces hardcoded MCP server version with parsed version string.
pkg/mcp/tools_healthcheck.go	Reports normalized version string in healthcheck output.
pkg/app/app.go	Uses the original injected version string for CLI output.
cmd/root.go	Delegates default version constant to version.DefaultVers.
go.mod	Adds a direct dependency on github.com/Masterminds/semver/v3.

---

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[codecov]

Codecov Report

❌ Patch coverage is 88.88889% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.33%. Comparing base (584c11e) to head (f7c7f8d).
⚠️ Report is 114 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/version/version.go	85.71%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3832      +/-   ##
==========================================
- Coverage   57.03%   53.33%   -3.70%     
==========================================
  Files         182      201      +19     
  Lines       21376    23456    +2080     
==========================================
+ Hits        12191    12511     +320     
- Misses       7953     9699    +1746     
- Partials     1232     1246      +14     

Flag	Coverage Δ
e2e	33.71% <44.44%> (-2.10%)	⬇️
e2e go	?
e2e node	25.97% <43.75%> (-1.29%)	⬇️
e2e python	?
e2e quarkus	?
e2e rust	?
e2e springboot	?
e2e typescript	26.06% <43.75%> (-1.30%)	⬇️
e2e-config-ci	26.77% <43.75%> (-1.40%)	⬇️
integration	15.76% <18.75%> (-1.41%)	⬇️
unit macos-14	42.27% <81.25%> (-2.83%)	⬇️
unit macos-latest	42.27% <81.25%> (-2.83%)	⬇️
unit ubuntu-24.04-arm	42.57% <83.33%> (-2.77%)	⬇️
unit ubuntu-latest	43.13% <81.25%> (-2.91%)	⬇️
unit windows-latest	42.33% <81.25%> (-2.81%)	⬇️

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[lkingland]

Let's keep the version package a simple "string-stamp" library. Move the default from the CLI in there like you did. Set Vers to that default. Then it's up to the user if they want it as a Semver or not.

Finally, we'd need a patch the Makefile to ensure it doesn't overwrite the default with an empty value (-X pkg.Var= with an empty value clears the Go initializer).

Here's the whole version package:

package version

const Default = "v0.0.0+source"

var (
	Vers = Default // overwritten by ldflags when make actually has a describe
	Kver string
	Hash string
)

No Get(), no Masterminds. Semver stays an exercise for the caller (func version already parses if it needs to).

And here's a proper conditional for the Makefile:

LDFLAGS :=
ifneq ($(VERS),)
LDFLAGS += -X knative.dev/func/pkg/version.Vers=$(VERS)
endif
ifneq ($(KVER),)
LDFLAGS += -X knative.dev/func/pkg/version.Kver=$(KVER)
endif
ifneq ($(HASH),)
LDFLAGS += -X knative.dev/func/pkg/version.Hash=$(HASH)
endif

MCP server can load it in on start:

s := &Server{
	prefix:  "func",
	version: version.Vers,
	// ...
}

Healthcheck can just use the member directly:

output = HealthcheckOutput{
	Status:  "ok",
	Message: "The MCP server is running!",
	Version: s.version,
}

CLI can use the strings directly, no .Get().Original() confusion:

// pkg/app/app.go
Version: cmd.Version{
	Vers: version.Vers,
	Kver: version.Kver,
	Hash: version.Hash,
}

// cmd/root.go
const DefaultVersion = version.Default

Furthermore, the check in cmd.version.go can be removed because of the Makefile hardening:

if v.Vers == "" { v.Vers = DefaultVersion }

Lastly, we can keep the leading v for now because a semver is a simple strings.TrimPrefix away, and this way we're coherent with Git/Go/Knative/Kubernetes.

[lkingland]

Let's keep the version package a simple "string-stamp" library. Move the default from the CLI in there like you did. Set Vers to that default. Then it's up to the user if they want it as a Semver or not.

Finally, we'd need a patch the Makefile to ensure it doesn't overwrite the default with an empty value (-X pkg.Var= with an empty value clears the Go initializer).

Here's the whole version package:

package version

const Default = "v0.0.0+source"

var (
	Vers = Default // overwritten by ldflags when make actually has a describe
	Kver string
	Hash string
)

No Get(), no Masterminds. Semver stays an exercise for the caller (func version already parses if it needs to).

And here's a proper conditional for the Makefile:

LDFLAGS :=
ifneq ($(VERS),)
LDFLAGS += -X knative.dev/func/pkg/version.Vers=$(VERS)
endif
ifneq ($(KVER),)
LDFLAGS += -X knative.dev/func/pkg/version.Kver=$(KVER)
endif
ifneq ($(HASH),)
LDFLAGS += -X knative.dev/func/pkg/version.Hash=$(HASH)
endif

(be sure to keep the existing LDFLAGS += -X ... SocatImage / TarImage / FuncUtilImage lines after it)

MCP server can load it in on new:

s := &Server{
	prefix:  "func",
	version: version.Vers,
	// ...
}

i := mcp.NewServer(&mcp.Implementation{
    Name:    name,
    Title:   title,
    Version: s.version, // same stamp
}, ...)

Healthcheck can just use the member directly:

output = HealthcheckOutput{
	Status:  "ok",
	Message: "The MCP server is running!",
	Version: s.version,
}

CLI can use the strings directly, no .Get().Original() confusion:

// pkg/app/app.go
Version: cmd.Version{
	Vers: version.Vers,
	Kver: version.Kver,
	Hash: version.Hash,
}

// cmd/root.go
const DefaultVersion = version.Default

Furthermore, the check in cmd/version.go can be removed because of the Makefile hardening:

if v.Vers == "" { v.Vers = DefaultVersion }

Lastly, we can keep the leading v for now because a semver is a simple strings.TrimPrefix away in most cases, and this way we're coherent with Git/Go/Knative/Kubernetes.

[knative-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Ankitsinghsisodya
Once this PR has been reviewed and has the lgtm label, please ask for approval from lkingland. For more information see the Code Review Process.

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[knative-prow]

@Ankitsinghsisodya: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
unit-tests_func_main	0d86f23	link	true	/test unit-tests

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[Ankitsinghsisodya]

@lkingland Can you re run the tests?