feat(semver): support resolving with lowest version

Closes #110

site/docs/config/version-groups.mdx

@@ -229,3 +229,25 @@ that the dependency is not present in the earlier packages in the array.
   ]
 }
 ```
+
+## `preferVersion` string
+
+<Pills optional />
+
+Defaults to `highestSemver` but can be optionally changed to `lowestSemver`.
+
+To set this as your standard policy, create a version group which applies to
+every dependency as the last item in your `versionGroups` array. You can also
+just set this for some of the packages if you need to.
+
+```json title="Choose the lowest valid semver version when fixing mismatches"
+{
+  "versionGroups": [
+    {
+      "dependencies": ["**"],
+      "packages": ["**"],
+      "preferVersion": "lowestSemver"
+    }
+  ]
+}
+```

src/bin-list-mismatches/list-mismatches.ts

@@ -33,7 +33,7 @@ export function listMismatches(ctx: Syncpack.Ctx): Syncpack.Ctx {
       if (instanceGroup.hasWorkspaceInstance()) {
         return logWorkspaceMismatch(instanceGroup);
       }
-      logHighestVersionMismatch(instanceGroup);
+      logHighLowVersionMismatch(instanceGroup);
     });
   });
 
@@ -109,12 +109,17 @@ export function listMismatches(ctx: Syncpack.Ctx): Syncpack.Ctx {
     });
   }
 
-  function logHighestVersionMismatch(instanceGroup: InstanceGroup) {
+  function logHighLowVersionMismatch(instanceGroup: InstanceGroup) {
     const name = instanceGroup.name;
+    const preference = (
+      instanceGroup.versionGroup
+        .groupConfig as Syncpack.Config.VersionGroup.Standard
+    ).preferVersion;
+    const direction = preference === 'highestSemver' ? 'highest' : 'lowest';
     const expected = R.getExn(instanceGroup.getExpectedVersion());
     log.invalid(
       name,
-      chalk`{reset.green ${expected}} {dim is the highest valid semver version in use}`,
+      chalk`{reset.green ${expected}} {dim is the ${direction} valid semver version in use}`,
     );
     // Log each of the dependencies mismatches
     instanceGroup.instances.forEach((instance) => {

src/get-context/get-config/schema/index.ts

@@ -1,12 +1,11 @@
 import { z } from 'zod';
 import { DEFAULT_CONFIG } from '../../../constants';
+import { nonEmptyString } from './lib/non-empty-string';
 import * as paths from './paths';
 import * as semverGroup from './semver-group';
 import * as semverRange from './semver-range';
 import * as versionGroup from './version-group';
 
-const nonEmptyString = z.string().trim().min(1);
-
 const cliOnly = {
   configPath: z.string().optional(),
   types: z.string().default(''),
@@ -36,7 +35,7 @@ const privateOnly = {
   allTypes: z.array(paths.pathDefinition),
   enabledTypes: z.array(paths.pathDefinition),
   defaultSemverGroup: semverGroup.base,
-  defaultVersionGroup: versionGroup.base,
+  defaultVersionGroup: versionGroup.defaultGroup,
 } as const;
 
 export const Private = z.object({

src/get-context/get-config/schema/lib/non-empty-string.ts

@@ -0,0 +1,3 @@
+import { z } from 'zod';
+
+export const nonEmptyString = z.string().trim().min(1);

src/get-context/get-config/schema/version-group.ts

@@ -1,9 +1,15 @@
 import { z } from 'zod';
 import { baseGroupFields } from './base-group';
+import { nonEmptyString } from './lib/non-empty-string';
 
-const nonEmptyString = z.string().trim().min(1);
+const preferVersion = z
+  .enum(['highestSemver', 'lowestSemver'])
+  .optional()
+  .default('highestSemver');
 
-export const standard = z.object(baseGroupFields).strict();
+export const standard = z
+  .object({ ...baseGroupFields, preferVersion })
+  .strict();
 
 export const banned = z
   .object({ ...baseGroupFields, isBanned: z.literal(true) })
@@ -21,8 +27,8 @@ export const snappedTo = z
   .object({ ...baseGroupFields, snapTo: z.array(nonEmptyString) })
   .strict();
 
-export const base = z
-  .object({ ...baseGroupFields, isDefault: z.literal(true) })
+export const defaultGroup = z
+  .object({ ...baseGroupFields, isDefault: z.literal(true), preferVersion })
   .strict();
 
 export const any = z.union([
@@ -31,5 +37,5 @@ export const any = z.union([
   ignored,
   pinned,
   snappedTo,
-  base,
+  defaultGroup,
 ]);

src/get-context/get-groups/version-group/instance-group/get-highest-version.spec.ts

@@ -1,40 +1,60 @@
 import { R } from '@mobily/ts-belt';
 import 'expect-more-jest';
+import { shuffle } from '../../../../../test/shuffle';
 import { getHighestVersion } from './get-highest-version';
 
-const shuffle = (array: string[]): string[] => {
-  for (let i = array.length - 1; i > 0; i--) {
-    const j = Math.floor(Math.random() * (i + 1));
-    [array[i], array[j]] = [array[j], array[i]];
-  }
-  return array;
-};
-
 describe('getHighestVersion', () => {
-  it('returns the newest version from an array of versions', () => {
-    const a = ['<1.0.0'];
-    const b = shuffle([...a, '<=1.0.0']);
-    const c = shuffle([...b, '1']);
-    const d = shuffle([...c, '1.0.0']);
-    const e = shuffle([...d, '~1.0.0']);
-    const f = shuffle([...e, '1.x.x']);
-    const g = shuffle([...f, '^1.0.0']);
-    const h = shuffle([...g, '>=1.0.0']);
-    const i = shuffle([...h, '>1.0.0']);
-    const j = shuffle([...i, '*']);
-    // valid semver
+  const a = ['<1.0.0'];
+  const b = shuffle([...a, '<=1.0.0']);
+  const c = shuffle([...b, '1']);
+  const d = shuffle([...c, '1.0.0']);
+  const e = shuffle([...d, '~1.0.0']);
+  const f = shuffle([...e, '1.x.x']);
+  const g = shuffle([...f, '^1.0.0']);
+  const h = shuffle([...g, '>=1.0.0']);
+  const i = shuffle([...h, '>1.0.0']);
+  const j = shuffle([...i, '*']);
+
+  // "1" and "1.0.0" are equal and first match wins
+  const eitherFormat = expect.stringMatching(/^(1|1\.0\.0)$/);
+
+  it('returns "<1.0.0" when it is the only version', () => {
     expect(getHighestVersion(a)).toEqual(R.Ok('<1.0.0'));
+  });
+
+  it('returns "<=1.0.0" when added', () => {
     expect(getHighestVersion(b)).toEqual(R.Ok('<=1.0.0'));
+  });
+
+  it('returns "1" when added', () => {
     expect(getHighestVersion(c)).toEqual(R.Ok('1'));
-    expect(getHighestVersion(d)).toEqual(
-      // "1" and "1.0.0" are equal and first match wins
-      R.Ok(expect.stringMatching(/^(1|1\.0\.0)$/)),
-    );
+  });
+
+  it('returns "1.0.0" when added', () => {
+    expect(getHighestVersion(d)).toEqual(R.Ok(eitherFormat));
+  });
+
+  it('returns "~1.0.0" when added', () => {
     expect(getHighestVersion(e)).toEqual(R.Ok('~1.0.0'));
+  });
+
+  it('returns "1.x.x" when added', () => {
     expect(getHighestVersion(f)).toEqual(R.Ok('1.x.x'));
+  });
+
+  it('returns "^1.0.0" when added', () => {
     expect(getHighestVersion(g)).toEqual(R.Ok('^1.0.0'));
+  });
+
+  it('returns ">=1.0.0" when added', () => {
     expect(getHighestVersion(h)).toEqual(R.Ok('>=1.0.0'));
+  });
+
+  it('returns ">1.0.0" when added', () => {
     expect(getHighestVersion(i)).toEqual(R.Ok('>1.0.0'));
+  });
+
+  it('returns "*" when added', () => {
     expect(getHighestVersion(j)).toEqual(R.Ok('*'));
   });
 });

src/get-context/get-groups/version-group/instance-group/get-highest-version.ts

@@ -1,7 +1,7 @@
 import { R } from '@mobily/ts-belt';
 import { BaseError } from '../../../../lib/error';
 import { clean } from './lib/clean';
-import { compareSemver } from './lib/compare-semver';
+import { compareGt } from './lib/compare-semver';
 import { getRangeScore } from './lib/get-range-score';
 
 interface HighestVersion {
@@ -15,7 +15,7 @@ export function getHighestVersion(
   let highest: HighestVersion | undefined;
 
   for (const withRange of versions) {
-    switch (compareSemver(withRange, highest?.semver)) {
+    switch (compareGt(withRange, highest?.semver)) {
       // highest possible, quit early
       case '*': {
         return R.Ok(withRange);

src/get-context/get-groups/version-group/instance-group/get-lowest-version.spec.ts

@@ -0,0 +1,60 @@
+import { R } from '@mobily/ts-belt';
+import 'expect-more-jest';
+import { shuffle } from '../../../../../test/shuffle';
+import { getLowestVersion } from './get-lowest-version';
+
+describe('getLowestVersion', () => {
+  const a = ['*'];
+  const b = shuffle([...a, '>1.0.0']);
+  const c = shuffle([...b, '>=1.0.0']);
+  const d = shuffle([...c, '^1.0.0']);
+  const e = shuffle([...d, '1.x.x']);
+  const f = shuffle([...e, '~1.0.0']);
+  const g = shuffle([...f, '1.0.0']);
+  const h = shuffle([...g, '1']);
+  const i = shuffle([...h, '<=1.0.0']);
+  const j = shuffle([...i, '<1.0.0']);
+
+  // "1" and "1.0.0" are equal and first match wins
+  const eitherFormat = expect.stringMatching(/^(1|1\.0\.0)$/);
+
+  it('returns "*" when it is the only version', () => {
+    expect(getLowestVersion(a)).toEqual(R.Ok('*'));
+  });
+
+  it('returns ">1.0.0" when added', () => {
+    expect(getLowestVersion(b)).toEqual(R.Ok('>1.0.0'));
+  });
+
+  it('returns ">=1.0.0" when added', () => {
+    expect(getLowestVersion(c)).toEqual(R.Ok('>=1.0.0'));
+  });
+
+  it('returns "^1.0.0" when added', () => {
+    expect(getLowestVersion(d)).toEqual(R.Ok('^1.0.0'));
+  });
+
+  it('returns "1.x.x" when added', () => {
+    expect(getLowestVersion(e)).toEqual(R.Ok('1.x.x'));
+  });
+
+  it('returns "~1.0.0" when added', () => {
+    expect(getLowestVersion(f)).toEqual(R.Ok('~1.0.0'));
+  });
+
+  it('returns "1.0.0" when added', () => {
+    expect(getLowestVersion(g)).toEqual(R.Ok('1.0.0'));
+  });
+
+  it('returns "1" when added', () => {
+    expect(getLowestVersion(h)).toEqual(R.Ok(eitherFormat));
+  });
+
+  it('returns "<=1.0.0" when added', () => {
+    expect(getLowestVersion(i)).toEqual(R.Ok('<=1.0.0'));
+  });
+
+  it('returns "<1.0.0" when added', () => {
+    expect(getLowestVersion(j)).toEqual(R.Ok('<1.0.0'));
+  });
+});

src/get-context/get-groups/version-group/instance-group/get-lowest-version.ts

@@ -0,0 +1,49 @@
+import { R } from '@mobily/ts-belt';
+import { BaseError } from '../../../../lib/error';
+import { clean } from './lib/clean';
+import { compareLt } from './lib/compare-semver';
+import { getRangeScore } from './lib/get-range-score';
+
+interface LowestVersion {
+  withRange: string;
+  semver: string;
+}
+
+export function getLowestVersion(
+  versions: string[],
+): R.Result<string, BaseError> {
+  let lowest: LowestVersion | undefined;
+
+  for (const withRange of versions) {
+    switch (compareLt(withRange, lowest?.semver)) {
+      // lowest possible, quit early
+      case '*': {
+        if (!lowest) lowest = { withRange: '*', semver: '*' };
+        continue;
+      }
+      // impossible to know how the user wants to resolve unsupported versions
+      case 'invalid': {
+        return R.Error(new BaseError(`"${withRange}" is not supported`));
+      }
+      // we found a new lowest version
+      case 'lt': {
+        lowest = newLowestVersion(withRange);
+        continue;
+      }
+      // versions are the same, but one range might be greedier than another
+      case 'eq': {
+        const score = getRangeScore(withRange);
+        const lowestScore = getRangeScore(`${lowest?.withRange}`);
+        if (score < lowestScore) lowest = newLowestVersion(withRange);
+      }
+    }
+  }
+
+  return lowest && lowest.withRange
+    ? R.Ok(lowest.withRange)
+    : R.Error(new BaseError(`getLowestVersion(): did not return a version`));
+}
+
+function newLowestVersion(withRange: string): LowestVersion {
+  return { withRange, semver: clean(withRange) };
+}

src/get-context/get-groups/version-group/instance-group/index.ts

@@ -4,9 +4,13 @@ import type { VersionGroup } from '..';
 import { BaseError } from '../../../../lib/error';
 import { isSemver } from '../../../../lib/is-semver';
 import { printStrings } from '../../../../lib/print-strings';
+import type { Syncpack } from '../../../../types';
 import { props } from '../../../get-package-json-files/get-patterns/props';
 import type { Instance } from '../../../get-package-json-files/package-json-file/instance';
 import { getHighestVersion } from './get-highest-version';
+import { getLowestVersion } from './get-lowest-version';
+
+type Standard = Syncpack.Config.VersionGroup.Standard;
 
 export const DELETE = Symbol('DELETE');
 export type Delete = typeof DELETE;
@@ -70,14 +74,22 @@ export class InstanceGroup {
         ),
       );
     }
-    return this.getHighestVersion();
+    return (versionGroup.groupConfig as Standard).preferVersion ===
+      'lowestSemver'
+      ? this.getLowestVersion()
+      : this.getHighestVersion();
   }
 
   /** If all versions are valid semver, return the newest one */
   getHighestVersion(): R.Result<string, BaseError> {
     return getHighestVersion(this.getUniqueVersions());
   }
 
+  /** If all versions are valid semver, return the lowest one */
+  getLowestVersion(): R.Result<string, BaseError> {
+    return getLowestVersion(this.getUniqueVersions());
+  }
+
   /** Get the first version matched by the `snapTo` packages */
   getSnappedVersion(): R.Result<string, BaseError> {
     return pipe(