From 6f223944221ae6bf397d0082b2f7396fead5c3fc Mon Sep 17 00:00:00 2001
From: Michael Jumper <mjumper@apache.org>
Date: Tue, 10 Feb 2026 23:16:58 -0800
Subject: [PATCH] GUACAMOLE-2139: Fail build if licenses would be downloaded
 (unless explicitly overridden).

---
 doc/licenses/generate-license-files.sh | 20 +++++++++++++++++---
 pom.xml                                |  6 ++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/doc/licenses/generate-license-files.sh b/doc/licenses/generate-license-files.sh
index 62b678a19..5d43811b9 100755
--- a/doc/licenses/generate-license-files.sh
+++ b/doc/licenses/generate-license-files.sh
@@ -49,7 +49,17 @@
 # errors are encountered, failing the build. If this is undesirable (dependency
 # changes are being tested, a full list of all license errors across all
 # projects is needed, etc.), set the IGNORE_LICENSE_ERRORS environment variable
-# to "true".
+# to "true" (by building with "-DignoreLicenseErrors" specified).
+#
+# Downloading licenses automatically
+# ----------------------------------
+#
+# By default, this script will flag a license error if license information is
+# missing for any dependency. If license information can be downloaded from a
+# declared source (any of the "Source" URLs in the license information files),
+# this script can be instructed to automatically update license information
+# files by setting the DOWNLOAD_MISSING_LICENSES environment variable to
+# "true" (by building with "-DdownloadMissingLicenses" specified).
 #
 # Structure of license information
 # --------------------------------
@@ -557,8 +567,12 @@ EOF
     find "$LICENSE_INFO_DIR" -type f | xargs grep -l '^#[[:space:]]*Source:' \
         | while read FILENAME; do
         if [ -z "`get_license "$FILENAME" "$VERSION"`" ]; then
-            info "Downloading updated `basename "$FILENAME"` for `basename "$LICENSE_INFO_DIR"` ($VERSION)..."
-            append_license "$FILENAME" "$VERSION"
+            if [ "$DOWNLOAD_MISSING_LICENSES" = "true" ]; then
+                info "Downloading updated `basename "$FILENAME"` for `basename "$LICENSE_INFO_DIR"` ($VERSION)..."
+                append_license "$FILENAME" "$VERSION"
+            else
+                error "Missing license information in `basename "$FILENAME"` for `basename "$LICENSE_INFO_DIR"` ($VERSION). Rebuild with \"-DdownloadMissingLicenses\" to automatically download."
+            fi
         fi
     done
 
diff --git a/pom.xml b/pom.xml
index 244d32c83..2f260fc6e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -64,6 +64,11 @@
             or missing license headers). -->
         <ignoreLicenseErrors>false</ignoreLicenseErrors>
 
+        <!-- Set to "true" to automatically download license information
+            for any files that have "Source" headers but lack specific
+            information for the current version of that dependency. -->
+        <downloadMissingLicenses>false</downloadMissingLicenses>
+
         <!-- Set to "true" to perform automated checks for available dependency
             updates, including whether the declared versions of any
             dependencies have associated CVEs in NVD. Beware that both checks
@@ -278,6 +283,7 @@
                                 </arguments>
                                 <environmentVariables>
                                     <IGNORE_LICENSE_ERRORS>${ignoreLicenseErrors}</IGNORE_LICENSE_ERRORS>
+                                    <DOWNLOAD_MISSING_LICENSES>${downloadMissingLicenses}</DOWNLOAD_MISSING_LICENSES>
                                 </environmentVariables>
                             </configuration>
                             <goals>