fix: select the JDK that .sdkmanrc names when several of the same major are installed

docs/e2e.md

@@ -79,8 +79,13 @@ JDK, so `java` can only come from what vfox installs:
 4. Before any `vfox use`, a `.sdkmanrc` holding the SDKMAN identifier
    without the build number selects the JDK through `ParseLegacyFile`:
    `java=21.0.8-tem`, `java=21.0.5-jbr` (SDKMAN's name for JetBrains) or
-   `java=25.0.4.fx-librca` (its spelling of JavaFX builds). On Windows the
-   file is written with CRLF line endings.
+   `java=25.0.4.fx-librca` (its spelling of JavaFX builds). So does one
+   holding the installed version (`java=21.0.8+9-tem`). Both run next to an
+   empty install of another release whose version starts with the pinned
+   one (`21.0.80+1-tem`): vfox sorts installed versions as strings,
+   descending, so `vfox list java` must show it first, and
+   `ParseLegacyFile` used to take it as the first one starting with the
+   release. On Windows the file is written with CRLF line endings.
 5. After `vfox use --global`, the JDK on `PATH` reports the requested
    `java.version`, the runner's `os.arch` (`amd64` / `aarch64`, which also
    catches an x64 JDK emulated on Windows ARM64) and the distribution's

hooks/parse_legacy_file.lua

@@ -15,6 +15,7 @@
 local strings = require("vfox.strings")
 
 local distribution_version_parser = require("distribution_version")
+local installed_version = require("installed_version")
 
 --- Rewrites an SDKMAN identifier in the plugin's spelling, which parse_version
 --- reads. SDKMAN calls JetBrains jbr (the plugin's jb) and puts fx in the
@@ -64,52 +65,30 @@ function PLUGIN:ParseLegacyFile(ctx)
         return {}
     end
 
-    local versionArr = strings.split(fullVersion, "+")
-    local version = versionArr[1]
-    local build = versionArr[2]
-
+    local version = strings.split(fullVersion, "+")[1]
     local majorVersion = strings.split(version, ".")[1]
 
     --- Installed versions end in -<vendor> (OpenJDK's in nothing), then -fx for
     --- JavaFX builds: 21.0.8+9-tem, 21.0.12+7-zulu-fx, 25.0.2+10.
     local suffix = (vendor == "open" and "" or "-" .. vendor) .. (distributionVersion.javafx_bundled and "-fx" or "")
 
-    --- Whether installed version v is of this distribution and JavaFX flavour,
-    --- with a Java version starting with prefix.
-    local function matches(v, prefix)
-        local java_version = v:sub(1, #v - #suffix)
-        return java_version .. suffix == v
-            and (vendor ~= "open" or not strings.contains(java_version, "-"))
-            and strings.has_prefix(java_version, prefix)
-    end
-
     --- Get the list of versions of the current plugin installed
     --- (a plain call: vfox 1.x rejects the extra ctx argument of ctx:...).
-    local targetVersion
-    local versions = ctx.getInstalledVersions()
-    for _, v in ipairs(versions) do
-        --- It may be exactly the same, try it first.
-        if v == javaVersion then
-            targetVersion = v
-            break
-        end
-
-        if matches(v, version) then
-            targetVersion = v
-            break
-        end
-    end
-
-    if not targetVersion then
-        for _, v in ipairs(versions) do
-            if matches(v, majorVersion .. ".") then
-                targetVersion = v
-                break
-            end
-        end
+    --- vfox sorts it as strings, descending (21.0.8+9-tem, 21.0.12+8-tem,
+    --- 21.0.1+12-tem), so the first match is not the one to take.
+    local installed = {}
+    for _, v in ipairs(ctx.getInstalledVersions()) do
+        installed[v] = true
     end
 
+    --- The version itself (21.0.5+63130-jb), else the newest build of the
+    --- release, as SDKMAN's build numbers count its own rebuilds
+    --- (21.0.12+1.1-tem), else the newest installed release of the major
+    --- (21.0.12+8-tem for 21.0.3-tem).
+    local name = fullVersion .. suffix
     return {
-        version = targetVersion,
+        version = installed[name] and name
+            or installed_version.find(installed, version, suffix)
+            or installed_version.newest(installed, majorVersion .. ".", "^[%d.+]*$", suffix),
     }
 end

hooks/pre_use.lua

@@ -13,63 +13,7 @@
 -- limitations under the License.
 
 local distribution_version_parser = require("distribution_version")
-
---- Compares the numbers in two version strings one by one, missing ones as 0.
-local function compare(a, b)
-    local x, y = {}, {}
-    for number in a:gmatch("%d+") do
-        table.insert(x, tonumber(number))
-    end
-    for number in b:gmatch("%d+") do
-        table.insert(y, tonumber(number))
-    end
-    for i = 1, math.max(#x, #y) do
-        if (x[i] or 0) ~= (y[i] or 0) then
-            return (x[i] or 0) > (y[i] or 0) and 1 or -1
-        end
-    end
-    return 0
-end
-
---- Whether Java version a is newer than b: the release decides, then the
---- build (21.0.12.1+1 > 21.0.8+9 > 21.0.8+7 > 21+35).
-local function newer(a, b)
-    local a_release, a_build = a:match("^([^+]*)(.*)$")
-    local b_release, b_build = b:match("^([^+]*)(.*)$")
-    local order = compare(a_release, b_release)
-    return order > 0 or order == 0 and compare(a_build, b_build) > 0
-end
-
---- Returns the installed version that version .. suffix names. vfox uses the
---- returned version as is, while installed names carry the build number
---- PreInstall found, which the input may leave out. So, like PreInstall, take
---- the newest build of a release (21.0.8-tem selects 21.0.8+9-tem) and the
---- newest release of a bare major (21-tem selects 21.0.12.1+1-tem), unless the
---- name itself is installed. Without a match, return the name for vfox to
---- report as not installed.
-local function installed_version(installed_sdks, version, suffix)
-    local name = version .. suffix
-    if installed_sdks[name] then
-        return name
-    end
-    -- A bare major takes any release of it (21.0.12.1+1 for 21) but no EA build
-    -- (26-ea+13 for 26); other versions take only a build number (not
-    -- 21.0.12.1+1 for 21.0.12, nor 21.0.12+8 for 21.0.1).
-    local more = version:match("^%d+$") and "^[.+][%d.+]*$" or "^%+%d+$"
-    local best, best_version
-    for candidate in pairs(installed_sdks) do
-        local java_version = candidate:sub(1, #candidate - #suffix)
-        if
-            java_version .. suffix == candidate
-            and java_version:sub(1, #version) == version
-            and java_version:sub(#version + 1):find(more)
-            and (not best or newer(java_version, best_version))
-        then
-            best, best_version = candidate, java_version
-        end
-    end
-    return best or name
-end
+local installed_version = require("installed_version")
 
 function PLUGIN:PreUse(ctx)
     local input_version = ctx.version
@@ -91,8 +35,11 @@ function PLUGIN:PreUse(ctx)
         if distribution_version.distribution.short_name ~= "open" then
             suffix = "-" .. distribution_version.distribution.short_name .. suffix
         end
+        -- vfox uses the returned version as is, so return the installed one it
+        -- names or, without a match, the name for vfox to report as not installed.
+        local name = distribution_version.version .. suffix
         return {
-            version = installed_version(ctx.installedSdks or {}, distribution_version.version, suffix),
+            version = installed_version.find(ctx.installedSdks or {}, distribution_version.version, suffix) or name,
         }
     else
         return {

lib/installed_version.lua

@@ -0,0 +1,82 @@
+-- Copyright 2026 Han Li and contributors
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--   http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+
+--- Finds installed versions, which PreInstall names after the Java version,
+--- then -<short name> (nothing for OpenJDK), then -fx for JavaFX builds:
+--- 21.0.8+9-tem, 25.0.4+9-librca-fx, 25.0.2+10. installed is a table keyed by
+--- those names.
+local installed_version = {}
+
+--- Compares the numbers in two version strings one by one, missing ones as 0.
+local function compare(a, b)
+    local x, y = {}, {}
+    for number in a:gmatch("%d+") do
+        table.insert(x, tonumber(number))
+    end
+    for number in b:gmatch("%d+") do
+        table.insert(y, tonumber(number))
+    end
+    for i = 1, math.max(#x, #y) do
+        if (x[i] or 0) ~= (y[i] or 0) then
+            return (x[i] or 0) > (y[i] or 0) and 1 or -1
+        end
+    end
+    return 0
+end
+
+--- Whether Java version a is newer than b: the release decides, then the
+--- build (21.0.12.1+1 > 21.0.8+9 > 21.0.8+7 > 21+35).
+local function newer(a, b)
+    local a_release, a_build = a:match("^([^+]*)(.*)$")
+    local b_release, b_build = b:match("^([^+]*)(.*)$")
+    local order = compare(a_release, b_release)
+    return order > 0 or order == 0 and compare(a_build, b_build) > 0
+end
+
+--- Returns the newest installed version ending in suffix whose Java version is
+--- prefix followed by a rest that the pattern rest matches, or nil.
+function installed_version.newest(installed, prefix, rest, suffix)
+    local best, best_version
+    for candidate in pairs(installed) do
+        local java_version = candidate:sub(1, #candidate - #suffix)
+        if
+            java_version .. suffix == candidate
+            and java_version:sub(1, #prefix) == prefix
+            and java_version:sub(#prefix + 1):find(rest)
+            and (not best or newer(java_version, best_version))
+        then
+            best, best_version = candidate, java_version
+        end
+    end
+    return best
+end
+
+--- Returns the installed version that version .. suffix names, or nil. The
+--- input may leave out the build number PreInstall found, so, like PreInstall,
+--- take the newest build of a release (21.0.8-tem selects 21.0.8+9-tem) and
+--- the newest release of a bare major (21-tem selects 21.0.12.1+1-tem), unless
+--- the name itself is installed.
+function installed_version.find(installed, version, suffix)
+    local name = version .. suffix
+    if installed[name] then
+        return name
+    end
+    -- A bare major takes any release of it (21.0.12.1+1 for 21) but no EA build
+    -- (26-ea+13 for 26); other versions take only a build number (not
+    -- 21.0.12.1+1 for 21.0.12, nor 21.0.12+8 for 21.0.1).
+    local rest = version:match("^%d+$") and "^[.+][%d.+]*$" or "^%+%d+$"
+    return installed_version.newest(installed, version, rest, suffix)
+end
+
+return installed_version

tests/e2e/common/common.go

@@ -259,6 +259,15 @@ func MissingBuildSpec(distribution, version string) string {
 	return Spec(distribution, version+"+99")
 }
 
+// Decoy renders the installed name of another release whose version starts
+// with the pinned one (<version>0+1, e.g. 21.0.80+1-tem). vfox lists the
+// installed versions sorted as strings, descending, so it comes before the
+// pinned JDK (21.0.8+9-tem), and ParseLegacyFile, which took the first one
+// starting with the release, selected it (vfox-java#79).
+func Decoy(distribution, version string) string {
+	return Spec(distribution, version+"0+1")
+}
+
 // Major returns the leading version component: "21.0.8" -> "21".
 func Major(version string) string {
 	return strings.SplitN(version, ".", 2)[0]
@@ -406,6 +415,22 @@ func InstalledVersion(output string) string {
 	return ""
 }
 
+// listedVersion matches one `vfox list java` entry: "-> <version>", followed
+// by "<— current" for the version in use.
+var listedVersion = regexp.MustCompile(`^-> (\S+)`)
+
+// ListedVersions extracts the installed versions from `vfox list java`
+// output, in the order vfox lists them.
+func ListedVersions(output string) []string {
+	var versions []string
+	for _, line := range strings.Split(StripANSI(output), "\n") {
+		if m := listedVersion.FindStringSubmatch(strings.TrimRight(line, "\r")); m != nil {
+			versions = append(versions, m[1])
+		}
+	}
+	return versions
+}
+
 // unpackedTarball matches the "Unpacking <archive>..." line vfox prints
 // before extracting a .tar.gz.
 var unpackedTarball = regexp.MustCompile(`(?m)^Unpacking .*\.tar\.gz\.\.\.\r?$`)

tests/e2e/common/common_test.go

@@ -184,11 +184,11 @@ func TestRetryAttemptsDefault(t *testing.T) {
 }
 
 func TestSpecs(t *testing.T) {
-	for _, c := range []struct{ dist, version, spec, missing, missingBuild, legacy string }{
-		{"open", "25.0.2", "25.0.2", "25.0.99", "25.0.2+99", "25.0.2-open"},
-		{"tem", "21.0.8", "21.0.8-tem", "21.0.99-tem", "21.0.8+99-tem", "21.0.8-tem"},
-		{"librca-fx", "25.0.4", "25.0.4-librca-fx", "25.0.99-librca-fx", "25.0.4+99-librca-fx", "25.0.4.fx-librca"},
-		{"jb", "21.0.5", "21.0.5-jb", "21.0.99-jb", "21.0.5+99-jb", "21.0.5-jbr"},
+	for _, c := range []struct{ dist, version, spec, missing, missingBuild, legacy, decoy string }{
+		{"open", "25.0.2", "25.0.2", "25.0.99", "25.0.2+99", "25.0.2-open", "25.0.20+1"},
+		{"tem", "21.0.8", "21.0.8-tem", "21.0.99-tem", "21.0.8+99-tem", "21.0.8-tem", "21.0.80+1-tem"},
+		{"librca-fx", "25.0.4", "25.0.4-librca-fx", "25.0.99-librca-fx", "25.0.4+99-librca-fx", "25.0.4.fx-librca", "25.0.40+1-librca-fx"},
+		{"jb", "21.0.5", "21.0.5-jb", "21.0.99-jb", "21.0.5+99-jb", "21.0.5-jbr", "21.0.50+1-jb"},
 	} {
 		if got := Spec(c.dist, c.version); got != c.spec {
 			t.Errorf("Spec(%s, %s) = %q, want %q", c.dist, c.version, got, c.spec)
@@ -202,6 +202,9 @@ func TestSpecs(t *testing.T) {
 		if got := LegacyIdentifier(c.dist, c.version); got != c.legacy {
 			t.Errorf("LegacyIdentifier(%s, %s) = %q, want %q", c.dist, c.version, got, c.legacy)
 		}
+		if got := Decoy(c.dist, c.version); got != c.decoy {
+			t.Errorf("Decoy(%s, %s) = %q, want %q", c.dist, c.version, got, c.decoy)
+		}
 	}
 }
 
@@ -294,6 +297,17 @@ func TestInstalledVersion(t *testing.T) {
 	}
 }
 
+func TestListedVersions(t *testing.T) {
+	out := "-> 21.0.80+1-tem\r\n" +
+		"-> 21.0.8+9-tem \x1b[92m<— current\x1b[0m\r\n"
+	if got := ListedVersions(out); len(got) != 2 || got[0] != "21.0.80+1-tem" || got[1] != "21.0.8+9-tem" {
+		t.Errorf("ListedVersions = %q, want [21.0.80+1-tem 21.0.8+9-tem]", got)
+	}
+	if got := ListedVersions("no available version\n"); len(got) != 0 {
+		t.Errorf("ListedVersions = %q, want none", got)
+	}
+}
+
 func TestFromTarball(t *testing.T) {
 	tarball := "Preinstalling java@21.0.5+79248-jb...\r\n" +
 		"Unpacking C:\\Users\\John Doe\\.vfox\\cache\\java\\v-21.0.5+79248-jb\\jbrsdk_jcef-21.0.5-windows-x64-b792.48.tar.gz...\r\n"

tests/e2e/linux/e2e_test.go

@@ -171,7 +171,7 @@ func runOne(t *testing.T, ctx context.Context, image, platform, arch string, c c
 	installed := installJava(ctx, t, ctr, common.Spec(c.Distribution, version))
 	verifySearch(ctx, t, ctr, c.Distribution, installed)
 	// Before any `vfox use`, so java can only come from the legacy file.
-	verifyLegacyFile(ctx, t, ctr, c.Distribution, version, arch)
+	verifyLegacyFile(ctx, t, ctr, c.Distribution, version, installed, arch)
 
 	useJava(ctx, t, ctr, installed)
 	verifyToolchain(ctx, t, ctr, c.Distribution, version, installed, arch)

tests/e2e/linux/verify.go

@@ -53,20 +53,33 @@ func verifySearch(ctx context.Context, t *testing.T, ctr tc.Container, distribut
 // verifyLegacyFile proves ParseLegacyFile selects the installed JDK from a
 // .sdkmanrc (PLUGIN.legacyFilenames) holding the SDKMAN identifier without
 // the build number (e.g. java=21.0.8-tem, java=21.0.5-jbr,
-// java=25.0.4.fx-librca). It runs before any `vfox use`, so java can only
+// java=25.0.4.fx-librca) or the installed version itself (e.g.
+// java=21.0.8+9-tem), while vfox lists an empty install of another release
+// first (see common.Decoy). It runs before any `vfox use`, so java can only
 // come from the legacy file.
-func verifyLegacyFile(ctx context.Context, t *testing.T, ctr tc.Container, distribution, version, arch string) {
+func verifyLegacyFile(ctx context.Context, t *testing.T, ctr tc.Container, distribution, version, installed, arch string) {
 	t.Helper()
 	const dir = "/tmp/e2e-legacy-sdkmanrc"
-	identifier := common.LegacyIdentifier(distribution, version)
-	execOK(ctx, t, ctr, fmt.Sprintf("mkdir --parents %s && printf 'java=%%s\\n' %s > %s/.sdkmanrc",
-		dir, shQuote(identifier), dir))
-	// The probe activates inside its own exec, a fresh shell session, so no
-	// `vfox env` state cached by an earlier call can answer for the file.
-	out := execRetry(ctx, t, ctr, ".sdkmanrc java="+identifier, fmt.Sprintf(
-		`cd %s && eval "$(vfox activate bash)" && eval "$(vfox env -s bash)" && %s`, dir, showSettings))
-	common.CheckJava(t, out, distribution, version, arch, ".sdkmanrc java="+identifier)
-	t.Logf("PASS .sdkmanrc java=%s selects java %s", identifier, version)
+	// vfox counts a version as installed once its directory holds
+	// java-<version>; the decoy holds nothing more, so selecting it leaves
+	// no java on PATH.
+	decoy := common.Decoy(distribution, version)
+	decoyDir := `"${VFOX_HOME:-$HOME/.vfox}"/cache/java/` + shQuote("v-"+decoy)
+	execOK(ctx, t, ctr, "mkdir --parents "+decoyDir+"/"+shQuote("java-"+decoy))
+	listed := common.ListedVersions(execOK(ctx, t, ctr, "vfox list java"))
+	require.Equalf(t, []string{decoy, installed}, listed, "vfox list java must list the decoy %s first", decoy)
+
+	for _, identifier := range []string{common.LegacyIdentifier(distribution, version), installed} {
+		execOK(ctx, t, ctr, fmt.Sprintf("mkdir --parents %s && printf 'java=%%s\\n' %s > %s/.sdkmanrc",
+			dir, shQuote(identifier), dir))
+		// The probe activates inside its own exec, a fresh shell session, so no
+		// `vfox env` state cached by an earlier call can answer for the file.
+		out := execRetry(ctx, t, ctr, ".sdkmanrc java="+identifier, fmt.Sprintf(
+			`cd %s && eval "$(vfox activate bash)" && eval "$(vfox env -s bash)" && %s`, dir, showSettings))
+		common.CheckJava(t, out, distribution, version, arch, ".sdkmanrc java="+identifier)
+		t.Logf("PASS .sdkmanrc java=%s selects java %s, not %s", identifier, version, decoy)
+	}
+	execOK(ctx, t, ctr, "rm --recursive "+decoyDir)
 }
 
 // verifyToolchain runs java and javac through the activate hook and checks

tests/e2e/windows/e2e_test.go

@@ -248,7 +248,7 @@ func runOne(t *testing.T, ctx context.Context, image, platform, arch string, c c
 	installed := installJava(ctx, t, ctr, box, common.Spec(c.Distribution, version))
 	verifySearch(ctx, t, ctr, box, c.Distribution, installed)
 	// Before any `vfox use`, so java can only come from the legacy file.
-	verifyLegacyFile(ctx, t, ctr, box, c.Distribution, version, arch)
+	verifyLegacyFile(ctx, t, ctr, box, c.Distribution, version, installed, arch)
 
 	useJava(ctx, t, ctr, box, activation, installed)
 	verifyToolchain(ctx, t, ctr, box, activation, c.Distribution, version, installed, arch)