don't block on git credential prompts during version discovery

src/nimblepkg/versiondiscovery.nim

@@ -637,18 +637,33 @@ proc collectAllVersions*(package: PackageMinimalInfo, options: Options, getMinim
     ## Processes top-level dependencies in parallel (default) or sequentially (with --sync).
     ## Each branch gets its own visited set to avoid race conditions on shared state.
 
-    result = newTable[string, PackageVersions]()
-    if not options.parallelDiscovery:
-      for pv in package.requires:
-        var visitedCopy = initHashSet[PkgTuple]()
-        let resultTable = await processRequirements(pv, visitedCopy, getMinimalPackage, preferredPackages, options, nimBin)
-        mergeVersionTables(result[], resultTable[])
-    else:
-      var futures: seq[Future[TableRef[string, PackageVersions]]] = @[]
-      for pv in package.requires:
-        var visitedCopy = initHashSet[PkgTuple]()
-        futures.add processRequirements(pv, visitedCopy, getMinimalPackage, preferredPackages, options, nimBin)
-      await allFutures(futures)
-      for fut in futures:
-        if not fut.failed:
-          mergeVersionTables(result[], fut.read()[])
+    # During discovery we must never block on an interactive git credential
+    # prompt: a candidate version may require a repo that was deleted or renamed,
+    # and git would ask for a username/password for it. Dead URLs should fail
+    # fast so the version gets excluded. An explicit user-set value is respected;
+    # only the default (unset) case is forced to non-interactive. The previous
+    # value is restored afterwards, so actual installs keep interactive prompts
+    # for private repositories.
+    let hadTerminalPrompt = existsEnv("GIT_TERMINAL_PROMPT")
+    let prevTerminalPrompt = getEnv("GIT_TERMINAL_PROMPT")
+    if not hadTerminalPrompt:
+      putEnv("GIT_TERMINAL_PROMPT", "0")
+    try:
+      result = newTable[string, PackageVersions]()
+      if not options.parallelDiscovery:
+        for pv in package.requires:
+          var visitedCopy = initHashSet[PkgTuple]()
+          let resultTable = await processRequirements(pv, visitedCopy, getMinimalPackage, preferredPackages, options, nimBin)
+          mergeVersionTables(result[], resultTable[])
+      else:
+        var futures: seq[Future[TableRef[string, PackageVersions]]] = @[]
+        for pv in package.requires:
+          var visitedCopy = initHashSet[PkgTuple]()
+          futures.add processRequirements(pv, visitedCopy, getMinimalPackage, preferredPackages, options, nimBin)
+        await allFutures(futures)
+        for fut in futures:
+          if not fut.failed:
+            mergeVersionTables(result[], fut.read()[])
+    finally:
+      if hadTerminalPrompt: putEnv("GIT_TERMINAL_PROMPT", prevTerminalPrompt)
+      else: delEnv("GIT_TERMINAL_PROMPT")

tests/tester.nim

@@ -33,6 +33,7 @@ import tuninstall
 import tsat
 import tver
 import tversiondiscovery
+import tgitprompt
 import tniminstall
 import trequireflag
 import tdeclarativeparser

tests/tgitprompt.nim

@@ -0,0 +1,59 @@
+{.used.}
+# Tests for: git credential prompts are suppressed during version discovery.
+#
+# Version discovery probes many candidate URLs, including historical ones whose
+# repos may be deleted or renamed. For those, git would otherwise block on an
+# interactive `Username for 'https://github.com':` prompt. Discovery must never
+# prompt: dead URLs should fail fast so the version gets excluded. Actual
+# installs run outside discovery and keep interactive prompts for private
+# repositories.
+
+import unittest, os
+import std/[tables, options]
+import chronos
+import nimblepkg/[version, options, packageinfotypes, versiondiscovery]
+
+let nimBin = some("nim")
+
+proc collect(root: PackageMinimalInfo, mock: GetPackageMinimal): TableRef[string, PackageVersions] =
+  var options = initOptions()
+  options.parallelDiscovery = false
+  result = waitFor collectAllVersions(root, options, mock, nimBin = nimBin)
+
+suite "git credential prompts are suppressed during discovery":
+  test "discovery sets GIT_TERMINAL_PROMPT=0 only when the user didn't set it":
+    # An explicit user-set value is respected: discovery must not override it,
+    # and it must be restored afterwards so actual installs keep interactive
+    # prompts for private repositories.
+    var promptTotal = 0
+    var promptSeenZero = 0      # discovery forced non-interactive
+    var promptSeenUser = 0      # discovery kept the user's value
+    proc mock(pv: PkgTuple, options: Options, nimBin: Option[string]): Future[seq[PackageMinimalInfo]] {.async.} =
+      inc promptTotal
+      case getEnv("GIT_TERMINAL_PROMPT")
+      of "0": inc promptSeenZero
+      of "1": inc promptSeenUser
+      else: discard
+      return @[PackageMinimalInfo(name: "dep", version: newVersion("1.0.0"))]
+
+    let root = PackageMinimalInfo(
+      name: "root", version: newVersion("1.0.0"), isRoot: true,
+      requires: @[(name: "dep", ver: VersionRange(kind: verAny))])
+
+    # User set GIT_TERMINAL_PROMPT=1: it is respected, not overridden.
+    putEnv("GIT_TERMINAL_PROMPT", "1")
+    discard collect(root, mock)
+    check promptTotal > 0
+    check promptSeenUser == promptTotal
+    check promptSeenZero == 0
+    check getEnv("GIT_TERMINAL_PROMPT") == "1"
+
+    # When it wasn't set, discovery forces 0 and removes it afterwards.
+    delEnv("GIT_TERMINAL_PROMPT")
+    promptTotal = 0
+    promptSeenZero = 0
+    promptSeenUser = 0
+    discard collect(root, mock)
+    check promptSeenZero == promptTotal
+    check promptSeenUser == 0
+    check not existsEnv("GIT_TERMINAL_PROMPT")