angular/angular-cli · warning

Package dependency " " already exists with a different…

Error message

Package dependency "${name}" already exists with a different specifier. "${existingSpecifier}" will be replaced with "${specifier}".

What it means

addDependency (packages/schematics/angular/utility/dependency.ts) inserts a package into package.json. When the package already exists with a different version specifier, the default behavior (ExistingBehavior.Replace) warns that the existing specifier is being overwritten with the new one.

Solutions

1. Accept the replacement if the schematic's version is what you want; commit the updated package.json
2. If you need to keep your specifier, pin it back after the schematic runs or pre-update the dependency to a compatible range before running
3. Review the package.json diff after ng update/ng add to confirm no unexpected version changes

Example fix

// before (package.json)
"@angular/core": "~16.2.0"
// after schematic run (warned replacement)
"@angular/core": "^17.0.0"

// before running schematics that add deps, diff installed versions against expected
const pkg = require('./package.json');
const name = '@angular/core';
const expectedRange = '^17.0.0';
if (pkg.dependencies?.[name] && pkg.dependencies[name] !== expectedRange) {
  console.warn(`${name} will be replaced: ${pkg.dependencies[name]} -> ${expectedRange}`);
}

function dependencyWillChange(pkgJson, name, specifier) {
  const current = pkgJson?.dependencies?.[name] ?? pkgJson?.devDependencies?.[name];
  return typeof current === 'string' && current !== specifier;
}

When it happens

Trigger: Any schematic calling addDependency (directly or via addDependenciesToPackageJson) where package.json already lists the package under a different range, e.g. "~16.2.0" present while the schematic installs "^17.0.0".

Common situations: ng update / ng add flows where the workspace has a manually pinned or locally patched version of a dependency (e.g. @angular/core, zone.js, typescript) that differs from the schematic's target version.

Related errors

• Could not find version.
• Could not find "@angular/core" version.
• Could not find package.json
• Package was found but does not support schematics.
• Bootstrap call not found

AI-assisted analysis of angular/angular-cli@bb72145f9a (2026-08-30). Data as JSON: /api/errors/5c43fcbeaf325ced. Report an issue: GitHub.

Appendix: source

Thrown at packages/schematics/angular/utility/dependency.ts:201

      // Section is not present. The dependency can be added to a new object literal for the section.
      manifest[type] = { [name]: specifier };
    } else {
      const existingSpecifier = dependencySection[name];

      if (existingSpecifier === specifier) {
        // Already present with same specifier
        return;
      }

      if (existingSpecifier) {
        // Already present but different specifier

        if (existing === ExistingBehavior.Skip) {
          return;
        }

        // ExistingBehavior.Replace is the only other behavior currently
        context.logger.warn(
          `Package dependency "${name}" already exists with a different specifier. ` +
            `"${existingSpecifier}" will be replaced with "${specifier}".`,
        );
      }

      // Add new dependency in alphabetical order
      const entries = Object.entries(dependencySection);
      entries.push([name, specifier]);
      entries.sort((a, b) => a[0].localeCompare(b[0]));
      manifest[type] = Object.fromEntries(entries);
    }

    tree.overwrite(packageJsonPath, JSON.stringify(manifest, null, 2));

    const installPaths = installTasks.get(context) ?? new Set<string>();
    if (
      install === InstallBehavior.Always ||
      (install === InstallBehavior.Auto && !installPaths.has(packageJsonPath))

View on GitHub (pinned to bb72145f9a)