Skip stale latest prebuilts in installers

install.ps1

@@ -100,6 +100,85 @@ function Release-LatestTagDownloadUrl {
     return $null
 }
 
+function Version-Parts($Value) {
+    [regex]::Matches($Value, "\d+") | ForEach-Object { [int64]$_.Value }
+}
+
+function Compare-DoshVersion($Left, $Right) {
+    $leftParts = @(Version-Parts $Left)
+    $rightParts = @(Version-Parts $Right)
+    $width = [Math]::Max($leftParts.Count, $rightParts.Count)
+    for ($i = 0; $i -lt $width; $i++) {
+        $l = if ($i -lt $leftParts.Count) { $leftParts[$i] } else { 0 }
+        $r = if ($i -lt $rightParts.Count) { $rightParts[$i] } else { 0 }
+        if ($l -lt $r) { return -1 }
+        if ($l -gt $r) { return 1 }
+    }
+    return 0
+}
+
+function Current-SourceVersion {
+    if (Test-Path "Cargo.toml") {
+        $raw = Get-Content "Cargo.toml" -Raw
+    } else {
+        $web = Repo-WebBase $Repo
+        if (-not $web) {
+            return $null
+        }
+        try {
+            $raw = (Invoke-WebRequest -UseBasicParsing -Uri "$web/raw/branch/main/Cargo.toml").Content
+        }
+        catch {
+            return $null
+        }
+    }
+    if ($raw -match '(?m)^version = "([^"]+)"') {
+        return $Matches[1]
+    }
+    return $null
+}
+
+function Latest-ReleaseTag {
+    $web = Repo-WebBase $Repo
+    if (-not $web) {
+        return $null
+    }
+    try {
+        $response = Invoke-WebRequest -UseBasicParsing -Uri "$web/releases/latest" -MaximumRedirection 5
+        $effective = $null
+        if ($response.BaseResponse.ResponseUri) {
+            $effective = $response.BaseResponse.ResponseUri.AbsoluteUri
+        } elseif ($response.BaseResponse.RequestMessage -and $response.BaseResponse.RequestMessage.RequestUri) {
+            $effective = $response.BaseResponse.RequestMessage.RequestUri.AbsoluteUri
+        }
+        $prefix = "$web/releases/tag/"
+        if ($effective -and $effective.StartsWith($prefix)) {
+            return $effective.Substring($prefix.Length)
+        }
+    }
+    catch {
+        return $null
+    }
+    return $null
+}
+
+function Latest-ReleaseIsStale {
+    if ($BinaryUrl -or $BinaryBase -or $BinaryVersion -ne "latest") {
+        return $false
+    }
+    $latest = Latest-ReleaseTag
+    $current = Current-SourceVersion
+    if (-not $latest -or -not $current) {
+        return $false
+    }
+    $latestVersion = $latest.TrimStart("v")
+    if ((Compare-DoshVersion $latestVersion $current) -lt 0) {
+        Write-Warning "latest release $latestVersion is older than source $current; skipping stale prebuilt"
+        return $true
+    }
+    return $false
+}
+
 function Verify-ArchiveChecksum($Url, $Archive) {
     $checksumPath = "$Archive.sha256"
     try {
@@ -160,6 +239,9 @@ $configDir = Join-Path $HOME ".config\dosh"
 New-Item -ItemType Directory -Force -Path $bindir, $configDir | Out-Null
 
 function Install-Prebuilt {
+    if (Latest-ReleaseIsStale) {
+        return $false
+    }
     $url = Release-LatestTagDownloadUrl
     if (-not $url) {
         $url = Release-DownloadUrl