Merge bbefaea82e into 2896aed9f4

when building from a version-tagged commit with a clean tree, omit the
redundant git commit hash from the libp2p user agent string, saving
bytes in HTTP requests and libp2p identify. `ipfs version --commit`
still reports the full commit hash.

before (tagged release): kubo/0.37.0/6898472
after  (tagged release): kubo/0.37.0

non-tagged and dirty builds are unaffected.

cmd/ipfs/Rules.mk

@@ -12,7 +12,7 @@ PATH := $(realpath $(d)):$(PATH)
 # DEPS_OO_$(d) += merkledag/pb/merkledag.pb.go namesys/pb/namesys.pb.go
 # DEPS_OO_$(d) += pin/internal/pb/header.pb.go unixfs/pb/unixfs.pb.go
 
-$(d)_flags =-ldflags="-X "github.com/ipfs/kubo".CurrentCommit=$(git-hash)"
+$(d)_flags =-ldflags="-X "github.com/ipfs/kubo".CurrentCommit=$(git-hash) -X "github.com/ipfs/kubo".taggedRelease=$(git-tag)"
 
 $(IPFS_BIN_$(d)): GOFLAGS += $(cmd/ipfs_flags)
 

mk/git.mk

@@ -2,3 +2,11 @@
 # If that fails (e.g., we're building a docker image and have an empty objects
 # directory), assume the source isn't dirty and build anyways.
 git-hash:=$(shell git describe --always --match=NeVeRmAtCh --dirty 2>/dev/null || git rev-parse --short HEAD 2>/dev/null)
+
+# Detect if HEAD is a clean, tagged release. Used to omit redundant commit
+# hash from the libp2p user agent (the version number suffices).
+ifeq ($(findstring dirty,$(git-hash)),)
+  git-tag:=$(shell git tag --points-at HEAD 2>/dev/null | grep '^v' | head -1)
+else
+  git-tag:=
+endif

version.go

@@ -10,6 +10,12 @@ import (
 // CurrentCommit is the current git commit, this is set as a ldflag in the Makefile.
 var CurrentCommit string
 
+// taggedRelease is set via ldflag when building from a version-tagged commit
+// with a clean tree. When set, the commit hash is omitted from the libp2p
+// identify agent version and the HTTP user agent, since the version number
+// already identifies the exact source.
+var taggedRelease string
+
 // CurrentVersionNumber is the current application's version literal.
 const CurrentVersionNumber = "0.40.0-rc1"
 
@@ -19,15 +25,20 @@ const ApiVersion = "/kubo/" + CurrentVersionNumber + "/" //nolint
 const RepoVersion = 18
 
 // GetUserAgentVersion is the libp2p user agent used by go-ipfs.
-//
-// Note: This will end in `/` when no commit is available. This is expected.
 func GetUserAgentVersion() string {
-	userAgent := "kubo/" + CurrentVersionNumber + "/" + CurrentCommit
+	// For tagged release builds with a clean tree, the commit hash is
+	// redundant since the version number identifies the exact source.
+	commit := CurrentCommit
+	if taggedRelease != "" {
+		commit = ""
+	}
+
+	userAgent := "kubo/" + CurrentVersionNumber
+	if commit != "" {
+		userAgent += "/" + commit
+	}
 	if userAgentSuffix != "" {
-		if CurrentCommit != "" {
-			userAgent += "/"
-		}
-		userAgent += userAgentSuffix
+		userAgent += "/" + userAgentSuffix
 	}
 	return cmdutils.CleanAndTrim(userAgent)
 }