[BUG] bin doesnt work when incrementing arg with equals sign

[gonza7aav]

What / Why

Why it unshift an empty string into argv when an argument contains a "="?

// line 35 @ /bin/semver.js
let a = argv.shift()
const indexOfEqualSign = a.indexOf('=')
if (indexOfEqualSign !== -1) {
  a = a.slice(0, indexOfEqualSign)
  argv.unshift(a.slice(indexOfEqualSign + 1))
}

Let's suppose a contains an "=", then indexOfEqualSign won't be -1. Inside the if statement, it overwrites a with a slice of it (removing whatever is after the "="). After that, it inserts into argv another slice of a. But this slice starts at indexOfEqualSign + 1 (the part we just remove), so an empty string ("") will be returned by the slice and inserted by the unshift.

As I understood, the empty string doesn't affect the execution because it is filtered out at line 92. But, Why it bother to add an "", loop with it, add it to versions to finally remove from versions? I think I am missing something. Can someone explain it to me, please?

[lukekarrys]

Good catch! This is a bug:

❯ ./bin/semver.js --increment major 1.0.0
2.0.0

❯ ./bin/semver.js --increment=major 1.0.0
1.0.1

[ljharb]

An equals sign should be the preferred form with long options; it’d be great to audit all long options for this.

[lukekarrys]

I believe this is the fix. It should be getting the value before overwriting a. @ljharb I think this should fix all the long options, and I can add a test for this.

diff --git a/bin/semver.js b/bin/semver.js
index 779b8b0..8d1b557 100755
--- a/bin/semver.js
+++ b/bin/semver.js
@@ -37,8 +37,9 @@ const main = () => {
     let a = argv.shift()
     const indexOfEqualSign = a.indexOf('=')
     if (indexOfEqualSign !== -1) {
+      const value = a.slice(indexOfEqualSign + 1)
       a = a.slice(0, indexOfEqualSign)
-      argv.unshift(a.slice(indexOfEqualSign + 1))
+      argv.unshift(value)
     }
     switch (a) {
       case '-rv': case '-rev': case '--rev': case '--reverse':