René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Leading slash added to baseHref","articleBody":"### Command\n\nbuild\n\n### Is this a regression?\n\n- [x] Yes, this behavior used to work in the previous version\n\n### The previous version in which this bug was not present was\n\n20.3.11\n\n### Description\n\n**Expected behavior**\n\nThe value of the `href` attribute of the `\u003cbase\u003e` tag in the built `index.html` file should start with what's defined in the `baseHref` property of the builder.\n\n**Actual behavior**\n\nA leading `/` is added when the `baseHref` value does not start with one.\n\n**Impact**\n\nWe package our built apps inside docker images that process the `index.html` file on startup to replace certain strings matching `${...}` with values from environment variables.  This allows us to deliver portable docker images that can be deployed under different paths in different environments by simply setting the `BASE_HREF` environment variable.\n\nSo when building our app, we set `baseHref` in the build config to a string like `${BASE_HREF}`.\n\nWith Angular 20.3.11, this produced the following tag in `index.html` (with a localized build):\n\n```html\n\u003cbase href=\"${BASE_HREF}/en/\"/\u003e\n```\n\nSince Angular 20.3.13, we now get a leading slash added:\n\n```html\n\u003cbase href=\"/${BASE_HREF}/en/\"/\u003e\n```\n\nFor deployments where our `BASE_HREF` value is an empty string, this results in the base href value of `//en/` which is a protocol-relative URL and so all of our resources fail to load.\n\n### Minimal Reproduction\n\nCreate an Angular app with 20.3.13, set baseHref to a value that does not start with `/`, enable localization, build.\n\n### Exception or Error\n\n```text\n\n```\n\n### Your Environment\n\n```text\nAngular CLI: 20.3.13\nNode: 22.14.0\nPackage Manager: npm 10.9.2\nOS: darwin arm64\n    \n\nAngular: 20.3.15\n... animations, common, compiler, compiler-cli, core, forms\n... language-service, localize, platform-browser\n... platform-browser-dynamic, router\n\nPackage                      Version\n------------------------------------\n@angular-devkit/architect    0.2003.13\n@angular-devkit/core         20.3.13\n@angular-devkit/schematics   20.3.13\n@angular/build               20.3.13\n@angular/cdk                 20.2.14\n@angular/cli                 20.3.13\n@schematics/angular          20.3.13\nrxjs                         7.8.1\ntypescript                   5.9.3\nzone.js                      0.15.1\n```\n\n### Anything else relevant?\n\n_No response_","author":{"url":"https://github.com/daiscog","@type":"Person","name":"daiscog"},"datePublished":"2025-12-04T18:54:59.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/32030/angular-cli/issues/32030"}