From 724538aff3ca6fa9f884a12d20d2aa07ddfbe4f9 Mon Sep 17 00:00:00 2001
From: Bart Koelman <104792814+bart-vmware@users.noreply.github.com>
Date: Thu, 10 Sep 2026 12:04:26 +0200
Subject: [PATCH] Constrain aspire-starter port replacers to localhost: URLs

The dynamic port symbols (webHttpPortReplacer, apiServiceHttpPortReplacer,
appHostHttpPortReplacer, etc.) used a bare numeric "replaces" value, so the
template engine substituted that number everywhere in generated content, not
just in launchSettings.json. Since the default ports (5000, 7000, 5301, 7301,
15000, 17000, 19000, 20000, 21000, 22000) also occur as plain numeric literals
in vendored files such as wwwroot/lib/bootstrap/dist/js/bootstrap.bundle.js
(e.g. carousel interval: 5000), those files ended up with churned values that
differ between generated projects, making diffs across template runs noisy.

Add "onlyIf": [{"after": "localhost:"}] to each port replacer so substitution
only fires in "localhost:<port>" contexts, matching the fix already applied
upstream for the same class of bug (dotnet/aspnetcore#65165, dotnet/sdk#48811).

Fixes #20030
---
 .../.template.config/template.json            | 50 +++++++++++++++----
 1 file changed, 40 insertions(+), 10 deletions(-)

diff --git a/src/Aspire.ProjectTemplates/templates/aspire-starter/.template.config/template.json b/src/Aspire.ProjectTemplates/templates/aspire-starter/.template.config/template.json
index e1dff206598..fb8152ea90f 100644
--- a/src/Aspire.ProjectTemplates/templates/aspire-starter/.template.config/template.json
+++ b/src/Aspire.ProjectTemplates/templates/aspire-starter/.template.config/template.json
@@ -184,7 +184,10 @@
         "sourceVariableName": "appHostHttpPort",
         "fallbackVariableName": "appHostHttpPortGenerated"
       },
-      "replaces": "15000"
+      "replaces": "15000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "appHostOtlpHttpPort": {
       "type": "parameter",
@@ -206,7 +209,10 @@
         "sourceVariableName": "appHostOtlpHttpPort",
         "fallbackVariableName": "appHostOtlpHttpPortGenerated"
       },
-      "replaces": "19000"
+      "replaces": "19000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "appHostResourceHttpPort": {
       "type": "parameter",
@@ -228,7 +234,10 @@
         "sourceVariableName": "appHostResourceHttpPort",
         "fallbackVariableName": "appHostResourceHttpPortGenerated"
       },
-      "replaces": "20000"
+      "replaces": "20000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "appHostHttpsPort": {
       "type": "parameter",
@@ -250,7 +259,10 @@
         "sourceVariableName": "appHostHttpsPort",
         "fallbackVariableName": "appHostHttpsPortGenerated"
       },
-      "replaces": "17000"
+      "replaces": "17000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "appHostOtlpHttpsPort": {
       "type": "parameter",
@@ -272,7 +284,10 @@
         "sourceVariableName": "appHostOtlpHttpsPort",
         "fallbackVariableName": "appHostOtlpHttpsPortGenerated"
       },
-      "replaces": "21000"
+      "replaces": "21000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "appHostResourceHttpsPort": {
       "type": "parameter",
@@ -294,7 +309,10 @@
         "sourceVariableName": "appHostResourceHttpsPort",
         "fallbackVariableName": "appHostResourceHttpsPortGenerated"
       },
-      "replaces": "22000"
+      "replaces": "22000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "webHttpPort": {
       "type": "parameter",
@@ -316,7 +334,10 @@
         "sourceVariableName": "webHttpPort",
         "fallbackVariableName": "webHttpPortGenerated"
       },
-      "replaces": "5000"
+      "replaces": "5000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "webHttpsPort": {
       "type": "parameter",
@@ -338,7 +359,10 @@
         "sourceVariableName": "webHttpsPort",
         "fallbackVariableName": "webHttpsPortGenerated"
       },
-      "replaces": "7000"
+      "replaces": "7000",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "apiServiceHttpPort": {
       "type": "parameter",
@@ -360,7 +384,10 @@
         "sourceVariableName": "apiServiceHttpPort",
         "fallbackVariableName": "apiServiceHttpPortGenerated"
       },
-      "replaces": "5301"
+      "replaces": "5301",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "apiServiceHttpsPort": {
       "type": "parameter",
@@ -382,7 +409,10 @@
         "sourceVariableName": "apiServiceHttpsPort",
         "fallbackVariableName": "apiServiceHttpsPortGenerated"
       },
-      "replaces": "7301"
+      "replaces": "7301",
+      "onlyIf": [{
+        "after": "localhost:"
+      }]
     },
     "skipRestore": {
       "type": "parameter",